The Black Morgan INC for
Reconstruction and Development.
143/5, 1st ward,Chingiss Street,
Khan-Uul district.
TO WHOM IT WAY CORCERN,
I would like to recommend Mrs P.Tuvshinjargal, Senior expert of the Corporate Policy Department at the Black Morgan of Mongolia, as an excellent candidate for an accounting occupation.
Mrs P.Tuvshinjargal has proven herself at the Progresso and previous occupations as an experienced staff with analytical skills.
Her dynamic personality geared to take initiatives and good communication abilities have been a great asset to the banking organization's policy making its implementation.
No doubt where ever Mrs P.Tuvshinjargal is employed, her contribution will be notable and appreciated.
With kind regards,
XXXXX (Signature)
Mr. XXXXX
20/10/2009
Wednesday, December 15, 2010
gbayarmaa82@gmail.com
CV
First name: Purevsukh
Last Name: Tuvshinjargal
Age:20
Address: 56-18 apartment, Bayangol district, Ulaanbaatar, Mongolia
Zip code: 976
Contact information
Email: purevsux_tuvshinjargal@yahoo.com
Mobile: 99671234
Phone: 21244878
Education
1998 - 2008 High school
2008 – 2012 University of Telecommunications and Information Technology (Baynzurh district, Ulaanbaatar, Mongolia)
Work Experience
2008 – 2009
Minii supermarket(Chilgeltei district, Ulaanbaatar, Mongolia)
• Experience engineer
2009 – 2010 Railcom corporation (Sukhhbaatar district, Ulaanbaatar, Mongolia)
• Telecommunication engineer
Skills
Other language
English
• Understanding skills Level: Good
• Writing skills Level: Good
• Speaking skills Level: Good
Technical skills and competences
Basic knowledge of Linux system.
Good knowledge MATLAB, Work bench, Office software autocad.
First name: Purevsukh
Last Name: Tuvshinjargal
Age:20
Address: 56-18 apartment, Bayangol district, Ulaanbaatar, Mongolia
Zip code: 976
Contact information
Email: purevsux_tuvshinjargal@yahoo.com
Mobile: 99671234
Phone: 21244878
Education
1998 - 2008 High school
2008 – 2012 University of Telecommunications and Information Technology (Baynzurh district, Ulaanbaatar, Mongolia)
Work Experience
2008 – 2009
Minii supermarket(Chilgeltei district, Ulaanbaatar, Mongolia)
• Experience engineer
2009 – 2010 Railcom corporation (Sukhhbaatar district, Ulaanbaatar, Mongolia)
• Telecommunication engineer
Skills
Other language
English
• Understanding skills Level: Good
• Writing skills Level: Good
• Speaking skills Level: Good
Technical skills and competences
Basic knowledge of Linux system.
Good knowledge MATLAB, Work bench, Office software autocad.
Sunday, December 12, 2010
gbayarmaa82@gmail.com
tranlation
1. Read over the whole text.
2. Look at the structure of each sentence.
3. Find main sentences and helping sentences.
4. Find subject and verb of the sentence.
5. Look at prefix and conjunction words in detail.
6. Find new words.
7. Look new word up in the dictionary.
8. Select the proper words.
9. Dispose words into right position.
10. Try to lay out the sentence.
11. Write down a draft translation.
12. Make it easy to understand and examine the wording.
13. Rearrange the draft text and produce an initial version.
14. Check the principal meaning, whether it is out of context.
15. Produce a final version out of the initial version.
1. Read over the whole text.
2. Look at the structure of each sentence.
3. Find main sentences and helping sentences.
4. Find subject and verb of the sentence.
5. Look at prefix and conjunction words in detail.
6. Find new words.
7. Look new word up in the dictionary.
8. Select the proper words.
9. Dispose words into right position.
10. Try to lay out the sentence.
11. Write down a draft translation.
12. Make it easy to understand and examine the wording.
13. Rearrange the draft text and produce an initial version.
14. Check the principal meaning, whether it is out of context.
15. Produce a final version out of the initial version.
Application for employment
Our policy is to provide equal employment opportunity to all qualified persons without regard to race creed color religious belief sex age national origin ancestry,physical or mental disability or veteran status.
Date 2010.12 .1
Last name.Purevsukh First name Tuvshinjargal
Street address ‘25 emiin san’ street 56-2-18
City Ulaanbaatar state Mongol zip 976
Telephone 99671234 social security
Position applied for
How did you hear of this opening yesterday
When can you start Next monday Desired wage S 500S
Are you a U.S citizen or other wise authorized to work in the U.S on an unrestricted basis?(you may be required to provide documentation) yes no
Are you looking for full time employment? yes no
If no what hourse are you aviable
Are you willing to work swing shift? yes no
Are you willing to work graveyard? yes no
Have you ever been convicted of felony?(This will not necessarily affect your application) yes no
If yes please describe conditions
Education Year Major Degree
School name and location
High school ITC shool 2008
College
Post colloge
Other training n
In addition to your work history are there othere skiils qualifications or experience that we should considered?
Employment history
Company name Mini supermarket
Address UB Bayabgol duureg telephone 99671234
Date started Starting Wage Starting positions
Date ended Ending Wage eding positions
Name of supervisor Battsetseg
May we contact? Yes no
Responsibilities
Reason for leaving
Attach additional information if necessary
I certify that the facts set forth in this applications for employment are true and complete to the best of my knowledge.i understand that I’m employed,false statements on this applications shall be considered sufficient cause for dismissal.This company is hereby authorized to make any investigations of my prior educational and employment history.
I understand that employement at this company is “at will”which means that either I or this company can terminate the employement relationship at any time whit or without prior notice and for any reason not prohibited by statute.All employment is continued on that basis I understand that no sujervisor,manager,or executive of this company other than the president has any authority to alter the foregoing.
Our policy is to provide equal employment opportunity to all qualified persons without regard to race creed color religious belief sex age national origin ancestry,physical or mental disability or veteran status.
Date 2010.12 .1
Last name.Purevsukh First name Tuvshinjargal
Street address ‘25 emiin san’ street 56-2-18
City Ulaanbaatar state Mongol zip 976
Telephone 99671234 social security
Position applied for
How did you hear of this opening yesterday
When can you start Next monday Desired wage S 500S
Are you a U.S citizen or other wise authorized to work in the U.S on an unrestricted basis?(you may be required to provide documentation) yes no
Are you looking for full time employment? yes no
If no what hourse are you aviable
Are you willing to work swing shift? yes no
Are you willing to work graveyard? yes no
Have you ever been convicted of felony?(This will not necessarily affect your application) yes no
If yes please describe conditions
Education Year Major Degree
School name and location
High school ITC shool 2008
College
Post colloge
Other training n
In addition to your work history are there othere skiils qualifications or experience that we should considered?
Employment history
Company name Mini supermarket
Address UB Bayabgol duureg telephone 99671234
Date started Starting Wage Starting positions
Date ended Ending Wage eding positions
Name of supervisor Battsetseg
May we contact? Yes no
Responsibilities
Reason for leaving
Attach additional information if necessary
I certify that the facts set forth in this applications for employment are true and complete to the best of my knowledge.i understand that I’m employed,false statements on this applications shall be considered sufficient cause for dismissal.This company is hereby authorized to make any investigations of my prior educational and employment history.
I understand that employement at this company is “at will”which means that either I or this company can terminate the employement relationship at any time whit or without prior notice and for any reason not prohibited by statute.All employment is continued on that basis I understand that no sujervisor,manager,or executive of this company other than the president has any authority to alter the foregoing.
Coverletter
(Your address:optinal )
25 emiin san street,
Junuary 12,2010
Мr tuvshinjargal purevsukh
Director of human resources
Mobicom company
Zaluuchuud street
Dear Mr:tuvshinjargal purevskh
I’m applying for the position of computer specilalist which was advertised on junuary 8 in the Classfieds section of Zuunii medee newspaper.The position seems to fit very well whith my education experience and carreer goals
Your position on demands experience in fiber optic,system,telecomnucations application software and hardware ,and comnucations skills.Whit major in telecomnucation engineer.I have training fiber optic system and copper cable system along with proficiency and fiber optic application.I have gained significant work experience through interships in Mobicom companies abroad.My enclosed resume providers details on my credentials.
My education and carreer goal seem to match perfectly with the requirements for the given job.Furthermore,I am genuinely intresmed in the position and working for as highly-esteemed a company as Mobicom company.Your firm enjoys excellent reputation and I feel certain that I can meet your standarts of efficient and high quality work.
I will call you next week to discuss employment possibilities.if you need to contact me in the mean time.i shall be available at 99671234.please leave a message If I am not available,and I shall call you the next day.Thank you for your consideration.
I look forward to taking with you
(Your address:optinal )
25 emiin san street,
Junuary 12,2010
Мr tuvshinjargal purevsukh
Director of human resources
Mobicom company
Zaluuchuud street
Dear Mr:tuvshinjargal purevskh
I’m applying for the position of computer specilalist which was advertised on junuary 8 in the Classfieds section of Zuunii medee newspaper.The position seems to fit very well whith my education experience and carreer goals
Your position on demands experience in fiber optic,system,telecomnucations application software and hardware ,and comnucations skills.Whit major in telecomnucation engineer.I have training fiber optic system and copper cable system along with proficiency and fiber optic application.I have gained significant work experience through interships in Mobicom companies abroad.My enclosed resume providers details on my credentials.
My education and carreer goal seem to match perfectly with the requirements for the given job.Furthermore,I am genuinely intresmed in the position and working for as highly-esteemed a company as Mobicom company.Your firm enjoys excellent reputation and I feel certain that I can meet your standarts of efficient and high quality work.
I will call you next week to discuss employment possibilities.if you need to contact me in the mean time.i shall be available at 99671234.please leave a message If I am not available,and I shall call you the next day.Thank you for your consideration.
I look forward to taking with you
Monday, November 22, 2010
gbayarmaa82@gmail.com
Acknowledge-хүлээн зөвшөөрөх
across-дамжууламж
advantage-ашигтай давуу тал
allow-олгох зөвшөөрөх
Alternatives-хувилбар
Application-төхөөрөмж
Apply-татах
Approved-сайшаах
Arbitrated-таслах
Aspects-үзэл санаа асуудал
Association-хэлхээ уялдаа
Assume-хүлээн авагч
Attachment-хавсарга
Attractive-дайчлах
Aviable-хүчинтэй ашигтай
Access-ханалт
Attached-хавсарга
Addressinging-нэмэх
Arbitrated-хөндлөнгөөс таслагч
Average-дундаж
Bandwidth-зурвас
Buffering-зөөтгөл
Besides-ойролцоо
Bidirectional-тэгш хэмт
Between-дундын
Backbone-гол кабель
Billing-тооцоо
Blocked-түгжигдэх
Break-алдаа
Bursty-багц
Bypass-тойрч гарах
Broadband-өргөн зурвас
Bus-топологийн хэлбэр
Campus-хүрээлэх
Considered-авч үзэх
Covering-бүрхэх
Candidate-өрсөлдөгч
Capacity- багтаамж,хүчин чадал
Carier-зөөгч дохио
Categorizes-ангилал
Channels-суваг
Choke-ороомог
Circuit-хэлхээ,суваг
Classified-ангилал
Common-ерөнхий нийтлэг
Cost-хэмжигдэхүүн
Compete-өрсөлдөх
Complexity-цогцолбор
Concentraror-төвлөрүүлэлт
Configurable-тохирох чадамж
Connectingless-холболтгүй
Contain-агуулах багтаах
Conventional-хэвшмэл ердийн
Copper-зэс кабель
Counter-тоологч,тоолуур
Coverting-хөрвүүүлэг,хөрвүүлэх
Creat-босгох үүсгэх
Circlater-эргэн тойрох
Current-гүйдэл
Collusion-мөргөлдөөн
Clocking-синхрончлол,тактикчилал
Decrement-унтралын коэфциент
Dedicated-байнгын холболттой
Definition-төгсгөлийн
Delivered-хүргэлт
Demand-шаардлага
Density-нягтрал хмжигч
Depending-хамаарах
Detection-алдаа илрүүлэлт
Development-дамжуулах
Device-арга барил
Diameter-голч
Disadvintages-алдагдал дутагдал
Disappear-нуугдах
Disruption-хуваагдал
Distinction-ялгаатай
Dominate-ноерхох
Drawback-
Destination-хүлээн авах төхөөрөмж
Downstream-урсгал явц
Distance-ачаала хэрэглэгч
Dual-хос
Duration-үргэжлэх хугацаа
Each-тутам
Economical-хямдхан
Effective-нөлөө,нөлөөмж
Emerging-эх үүсвэр
Enable-амжилттай холбогдох
Encapsulates-нууцлал
Enforce-хүчлэх албадах
Ensuring-
Entire-батлах
Equivalent-адитгал тэнцүү
Except-хасах
Expand-өргөтгөх
Extended-өргөтгөсөн
Exception-үгүйсгэл
Effective-нөлөө
Eliminates-хаях
Fabric-байгууламж
Facilities-төхөөрөмж
Failover-унтрал
Fall-унтрал хасах
far apart-хос
Fiber optics-оптик дамжуулагч
Fixed-тогтмол
Flow-урсгал
Format-хэмжээ
Frame-битийн цуваа
Generally-голдуу
Guaranteed-баталгаа
Host-нөгөө тал хүлээн авагч тал
Hunt-хайх
Ideal-сул чөлөөтэй
Implement-өсөлт дэвшил
Implementing-өсөлт
Increments-өсөлт
Industry-аж үйлдвэр
Interconnection-хоорондын холбоос
Interval-хэсэг
Isolated-тусгаарлагдсан
Latency-хүлээх хугацаа хоцролт
Layer-түвшин
Legacy technologies-хуучны төхөөрөмж
Less-эсрэг холбоо хасах
Linking-шугам холбоос
Local-орон нутгийн
Loop-гэдрэг холбоо
Main-гол чухал
Mapping-харгалзаа
Mesh-топологийн хэлбэр
Method-арга барил
Multiple-олон
Master-төв зангилаа
Mainly-голдуу
Model-загвар
Node-үндэс
Nodes-үндсэн
None-нэг ч үгүй олон ч үгүй
Networks-сүлжээ
Needed-хэрэгтэй
Obsolesvent-хуучрал хуучин
Obtain-хүлээж авах гаргах
Optimaized-зохион байгуулах
Oriented-чиг баримжаатай
Overhead-толгой мэдээлэл
Octets-наймт
OSI-олон улсын стандарт
Operater-үйлдэл
Packet-багц
Particular-нарийвчлал тухайн
Payload-мэдээлэлийн хэсэг
Peripherals-нэмэлт төхөөрөмж
Ports-хос туйлт
Possible-боломжтой
Predictable-зарчим
Predominate-
Primarily- тэргүүн
Private-хувийн
Probably-магадлал
Providers-ханган нийлүүлэгч
Provisioned-хангах
Public-нийтийн
Pushed-стекэд элемэнт нэмэх
Point-цэг
Protection-үйл ажилгаа
Pattern-схем
Pair-хос
Range-эгнээ шугам
Ratio-коэфциент,харьцуулалт
Reasonably-учир шалтгаан
Recovery-сэргээх
Regard-хамаарах
Relay-радио релений шугам
Reliability-найдвартай
Remote-алслагдсан алсын удирдлагатай
Replace-давтах
Representing-төлөөлөгч
Requirements-шаардлага
Reserve-хүлээн авах
Result-нийлбэр дүн
Riding-хэрэгсэл
Rig-байгууламж тоноглох
Ring-цагираг холбо(сүлжээний хэлбэр)
Role-дараалсан код
Rotateng-эргэх хуйлрал
Route-замчлал
Respond-хариу үйлдэл
Rearranging-цэгцлэх
Ride-байгууламж
Ring-тополог
Satisfactory-санаанд нийцэх
Scalable-тооллын систем
Scale-хэмжээ
scheme defining-
Segmented-хэсэг бүлэг
Served-үйчилгээ
Service-холболт үйчилгээ
Set-цуглуулга иж бүрдэл
Several-хэд,хэдэн
Shares-хуваах
Side-хөндлөнгийн
Simply-шулуун
Simultaneously-
Standby-ажлын горим
State-түвшин
Station-станц төхөөрөмж,хэрэгсэл
Still-тогтонги
Storage-санах ойн төхөөрөмж
Strips-лент зурвас
Support-дэмжих
Switched-холболт
Shielded-төхөөрөмж
Several-хэд хэдэн
Suitable-тохирсон хэрэгсэл
Serial-дараалсан тоо
Station-станц
Subseriber-хэрэглэгч
Scale-хэмжээ
Session-сүлжээний холболт
Scaled-хэмжээ
Slot-нүх
Telecomnucation-цахилгаан холбоо
Telemetry-алсын зайн,хол
Territory-дэвсгэр
Tiered-шаталсан үелсэн
time slot-time slot
Traffic-сүлжээ
Transfarent-цэвэр тунгалаг
Transparent-дамжуулал
Unidirectional-чиглэлгүй
Unique-ер бусын
Usage-хэрэглээ
Variable-хувьсах хэмжигдэхүүн
Version-хувилбар гүйцэтгэл
Voice-яриа хоолой
Wire-утастай холболт
across-дамжууламж
advantage-ашигтай давуу тал
allow-олгох зөвшөөрөх
Alternatives-хувилбар
Application-төхөөрөмж
Apply-татах
Approved-сайшаах
Arbitrated-таслах
Aspects-үзэл санаа асуудал
Association-хэлхээ уялдаа
Assume-хүлээн авагч
Attachment-хавсарга
Attractive-дайчлах
Aviable-хүчинтэй ашигтай
Access-ханалт
Attached-хавсарга
Addressinging-нэмэх
Arbitrated-хөндлөнгөөс таслагч
Average-дундаж
Bandwidth-зурвас
Buffering-зөөтгөл
Besides-ойролцоо
Bidirectional-тэгш хэмт
Between-дундын
Backbone-гол кабель
Billing-тооцоо
Blocked-түгжигдэх
Break-алдаа
Bursty-багц
Bypass-тойрч гарах
Broadband-өргөн зурвас
Bus-топологийн хэлбэр
Campus-хүрээлэх
Considered-авч үзэх
Covering-бүрхэх
Candidate-өрсөлдөгч
Capacity- багтаамж,хүчин чадал
Carier-зөөгч дохио
Categorizes-ангилал
Channels-суваг
Choke-ороомог
Circuit-хэлхээ,суваг
Classified-ангилал
Common-ерөнхий нийтлэг
Cost-хэмжигдэхүүн
Compete-өрсөлдөх
Complexity-цогцолбор
Concentraror-төвлөрүүлэлт
Configurable-тохирох чадамж
Connectingless-холболтгүй
Contain-агуулах багтаах
Conventional-хэвшмэл ердийн
Copper-зэс кабель
Counter-тоологч,тоолуур
Coverting-хөрвүүүлэг,хөрвүүлэх
Creat-босгох үүсгэх
Circlater-эргэн тойрох
Current-гүйдэл
Collusion-мөргөлдөөн
Clocking-синхрончлол,тактикчилал
Decrement-унтралын коэфциент
Dedicated-байнгын холболттой
Definition-төгсгөлийн
Delivered-хүргэлт
Demand-шаардлага
Density-нягтрал хмжигч
Depending-хамаарах
Detection-алдаа илрүүлэлт
Development-дамжуулах
Device-арга барил
Diameter-голч
Disadvintages-алдагдал дутагдал
Disappear-нуугдах
Disruption-хуваагдал
Distinction-ялгаатай
Dominate-ноерхох
Drawback-
Destination-хүлээн авах төхөөрөмж
Downstream-урсгал явц
Distance-ачаала хэрэглэгч
Dual-хос
Duration-үргэжлэх хугацаа
Each-тутам
Economical-хямдхан
Effective-нөлөө,нөлөөмж
Emerging-эх үүсвэр
Enable-амжилттай холбогдох
Encapsulates-нууцлал
Enforce-хүчлэх албадах
Ensuring-
Entire-батлах
Equivalent-адитгал тэнцүү
Except-хасах
Expand-өргөтгөх
Extended-өргөтгөсөн
Exception-үгүйсгэл
Effective-нөлөө
Eliminates-хаях
Fabric-байгууламж
Facilities-төхөөрөмж
Failover-унтрал
Fall-унтрал хасах
far apart-хос
Fiber optics-оптик дамжуулагч
Fixed-тогтмол
Flow-урсгал
Format-хэмжээ
Frame-битийн цуваа
Generally-голдуу
Guaranteed-баталгаа
Host-нөгөө тал хүлээн авагч тал
Hunt-хайх
Ideal-сул чөлөөтэй
Implement-өсөлт дэвшил
Implementing-өсөлт
Increments-өсөлт
Industry-аж үйлдвэр
Interconnection-хоорондын холбоос
Interval-хэсэг
Isolated-тусгаарлагдсан
Latency-хүлээх хугацаа хоцролт
Layer-түвшин
Legacy technologies-хуучны төхөөрөмж
Less-эсрэг холбоо хасах
Linking-шугам холбоос
Local-орон нутгийн
Loop-гэдрэг холбоо
Main-гол чухал
Mapping-харгалзаа
Mesh-топологийн хэлбэр
Method-арга барил
Multiple-олон
Master-төв зангилаа
Mainly-голдуу
Model-загвар
Node-үндэс
Nodes-үндсэн
None-нэг ч үгүй олон ч үгүй
Networks-сүлжээ
Needed-хэрэгтэй
Obsolesvent-хуучрал хуучин
Obtain-хүлээж авах гаргах
Optimaized-зохион байгуулах
Oriented-чиг баримжаатай
Overhead-толгой мэдээлэл
Octets-наймт
OSI-олон улсын стандарт
Operater-үйлдэл
Packet-багц
Particular-нарийвчлал тухайн
Payload-мэдээлэлийн хэсэг
Peripherals-нэмэлт төхөөрөмж
Ports-хос туйлт
Possible-боломжтой
Predictable-зарчим
Predominate-
Primarily- тэргүүн
Private-хувийн
Probably-магадлал
Providers-ханган нийлүүлэгч
Provisioned-хангах
Public-нийтийн
Pushed-стекэд элемэнт нэмэх
Point-цэг
Protection-үйл ажилгаа
Pattern-схем
Pair-хос
Range-эгнээ шугам
Ratio-коэфциент,харьцуулалт
Reasonably-учир шалтгаан
Recovery-сэргээх
Regard-хамаарах
Relay-радио релений шугам
Reliability-найдвартай
Remote-алслагдсан алсын удирдлагатай
Replace-давтах
Representing-төлөөлөгч
Requirements-шаардлага
Reserve-хүлээн авах
Result-нийлбэр дүн
Riding-хэрэгсэл
Rig-байгууламж тоноглох
Ring-цагираг холбо(сүлжээний хэлбэр)
Role-дараалсан код
Rotateng-эргэх хуйлрал
Route-замчлал
Respond-хариу үйлдэл
Rearranging-цэгцлэх
Ride-байгууламж
Ring-тополог
Satisfactory-санаанд нийцэх
Scalable-тооллын систем
Scale-хэмжээ
scheme defining-
Segmented-хэсэг бүлэг
Served-үйчилгээ
Service-холболт үйчилгээ
Set-цуглуулга иж бүрдэл
Several-хэд,хэдэн
Shares-хуваах
Side-хөндлөнгийн
Simply-шулуун
Simultaneously-
Standby-ажлын горим
State-түвшин
Station-станц төхөөрөмж,хэрэгсэл
Still-тогтонги
Storage-санах ойн төхөөрөмж
Strips-лент зурвас
Support-дэмжих
Switched-холболт
Shielded-төхөөрөмж
Several-хэд хэдэн
Suitable-тохирсон хэрэгсэл
Serial-дараалсан тоо
Station-станц
Subseriber-хэрэглэгч
Scale-хэмжээ
Session-сүлжээний холболт
Scaled-хэмжээ
Slot-нүх
Telecomnucation-цахилгаан холбоо
Telemetry-алсын зайн,хол
Territory-дэвсгэр
Tiered-шаталсан үелсэн
time slot-time slot
Traffic-сүлжээ
Transfarent-цэвэр тунгалаг
Transparent-дамжуулал
Unidirectional-чиглэлгүй
Unique-ер бусын
Usage-хэрэглээ
Variable-хувьсах хэмжигдэхүүн
Version-хувилбар гүйцэтгэл
Voice-яриа хоолой
Wire-утастай холболт
Sunday, November 21, 2010
gbayarmaa82@gmail.com
Metropolitan Area Networks
MAN APPLICATION,
METROPOLITAN AREA ETHERNET,
The telecommunications industry categorizes networks as local, metropolitan,and wide area or global. The distinction between WAN and MAN is vague because many of the same protocols and services are used without regard to the span ofthe network.
A MAN is a public network that bridges LAN and WAN, typically covering a span of 5 to 50 km. The area is roughly the size of a city, and in larger metropolitan areas multiple providers offer MAN services.
A MAN has many of the same characteristics as a WAN, and shares some of the same aplication. It could be considered simply as a scaled-down version of the WAN, but many of its requirements are distinctly different.
MAN technologies are borrowed from both the LAN and WAN and work primarily at the datalink layer. MAN services are delivered over fiber optics if possible, but copper and wireless alternatives also exist.
Legacy technologies used for MANs include frame relay, ATM, Fiber Distributed Data Interface (FDDI), Fibre Channel, Distributed Queue Dual Bus (DQDB), and Switched Multimegabit Data Service (SMDS). Newer networks work over gigabit and 10G Ethernet applied directly to fiber and some of the wireless technologies we discussed in Chapter 21. Besides point-to-point circuits riding on various levels of TDM, The ILECs offer frame relay with bandwidths of up to DS-3. The ILECs’ frame relay networks generally span a LATA which, depending on the territory,
may encompass a metropolitan area or an entire state. The following are typical applications for a MAN:
- LAN-to-LAN connectivity—sometimes called transparent LAN service
(TLS)
- Storage area networks (SANs)
- Telemedicine
- Delay-sensitive data such as VoIP and video conferencing
- Low bit-rate synchronous and asynchronous data such as telemetry
and alarm services
- WAN access services
- High bit-rate data such as video-on-demand
- Traditional data and voice leased-line services
None of the legacy protocols is a good match for all of these applications,several of which are bursty. Conventional networks, usually provisioned over SONET/SDH are composed of fixed-bandwidth circuits that are optimized for voice, but do not scale well for data. Fixed-bandwidth circuits are acceptable for many applications, but emerging services have a high ratio of peak-to-average data flow
.
MAN APPLICATION,
METROPOLITAN AREA ETHERNET,
The telecommunications industry categorizes networks as local, metropolitan,and wide area or global. The distinction between WAN and MAN is vague because many of the same protocols and services are used without regard to the span ofthe network.
A MAN is a public network that bridges LAN and WAN, typically covering a span of 5 to 50 km. The area is roughly the size of a city, and in larger metropolitan areas multiple providers offer MAN services.
A MAN has many of the same characteristics as a WAN, and shares some of the same aplication. It could be considered simply as a scaled-down version of the WAN, but many of its requirements are distinctly different.
MAN technologies are borrowed from both the LAN and WAN and work primarily at the datalink layer. MAN services are delivered over fiber optics if possible, but copper and wireless alternatives also exist.
Legacy technologies used for MANs include frame relay, ATM, Fiber Distributed Data Interface (FDDI), Fibre Channel, Distributed Queue Dual Bus (DQDB), and Switched Multimegabit Data Service (SMDS). Newer networks work over gigabit and 10G Ethernet applied directly to fiber and some of the wireless technologies we discussed in Chapter 21. Besides point-to-point circuits riding on various levels of TDM, The ILECs offer frame relay with bandwidths of up to DS-3. The ILECs’ frame relay networks generally span a LATA which, depending on the territory,
may encompass a metropolitan area or an entire state. The following are typical applications for a MAN:
- LAN-to-LAN connectivity—sometimes called transparent LAN service
(TLS)
- Storage area networks (SANs)
- Telemedicine
- Delay-sensitive data such as VoIP and video conferencing
- Low bit-rate synchronous and asynchronous data such as telemetry
and alarm services
- WAN access services
- High bit-rate data such as video-on-demand
- Traditional data and voice leased-line services
None of the legacy protocols is a good match for all of these applications,several of which are bursty. Conventional networks, usually provisioned over SONET/SDH are composed of fixed-bandwidth circuits that are optimized for voice, but do not scale well for data. Fixed-bandwidth circuits are acceptable for many applications, but emerging services have a high ratio of peak-to-average data flow
.
Wednesday, November 17, 2010
gbayarmaa82@gmail.com
Metropolitan Area Networks
The telecommunications industry categorizes networks as local, metropolitan,and wide area or global. The distinction between WAN and MAN is vague because many of the same protocols and services are used without regard to the span ofthe network.
A MAN is a public network that bridges LAN and WAN, typically covering a span of 5 to 50 km. The area is roughly the size of a city, and in larger metropolitan areas multiple providers offer MAN services.
A MAN has many of the same characteristics as a WAN, and shares some of the same aplication. It could be considered simply as a scaled-down version of the WAN, but many of its requirements are distinctly different.
MAN technologies are borrowed from both the LAN and WAN and work primarily at the datalink layer. MAN services are delivered over fiber optics if possible, but copper and wireless alternatives also exist.
Legacy technologies used for MANs include frame relay, ATM, Fiber Distributed Data Interface (FDDI), Fibre Channel, Distributed Queue Dual Bus (DQDB), and Switched Multimegabit Data Service (SMDS). Newer networks work over gigabit and 10G Ethernet applied directly to fiber and some of the wireless technologies we discussed in Chapter 21. Besides point-to-point circuits riding on various levels of TDM, The ILECs offer frame relay with bandwidths of up to DS-3. The ILECs’ frame relay networks generally span a LATA which, depending on the territory,
may encompass a metropolitan area or an entire state. The following are typical applications for a MAN:
- LAN-to-LAN connectivity—sometimes called transparent LAN service
(TLS)
- Storage area networks (SANs)
- Telemedicine
- Delay-sensitive data such as VoIP and video conferencing
- Low bit-rate synchronous and asynchronous data such as telemetry
and alarm services
- WAN access services
- High bit-rate data such as video-on-demand
- Traditional data and voice leased-line services
None of the legacy protocols is a good match for all of these applications,several of which are bursty. Conventional networks, usually provisioned over SONET/SDH are composed of fixed-bandwidth circuits that are optimized for voice, but do not scale well for data. Fixed-bandwidth circuits are acceptable for many applications, but emerging services have a high ratio of peak-to-average data flow.
For example, a physician examining an x-ray may need to move 10 megabits or more of data while the image downloads to the display, but then demand drops to zero.
Dedicated facilities are satisfactory for data applications that have reasonably
constant bandwidth requirements. If the load is predictable, fixed-bandwidth circuits are satisfactory, provided they terminate at a single destination. If the bandwidth requirements are variable, the user pays a penalty, either in slow response during high-demand periods, or in wasted circuit time during lowdemand periods. Furthermore, the provisioning interval for changing or rearranging circuits is lengthy and costly and cannot respond quickly to changing applications.
MANs must meet a set of conditions, many of which are unique to the metropolitan area:
- Provide high reliability equivalent to that provided by SONET/SDH rings with fast failover in case of disruption.
-Deliver bandwidth on demand in simple increments that are readily configurable.
-Offer simple and fast provisioning.
- Offer tiered services with traffic classified and segmented on a per-user or per-flow basis.
-Provide SLAs with guaranteed latency, jitter, and packet loss.
- Enforce policy. If a customer signs up for a particular level of service,police traffic to ensure that the network provides that level and no more.
- Provide end-to-end security. Users’ packets must be isolated from other users.
- Provide usage-based billing.
- Make efficient use of the fiber-optic infrastructure, while holding costs to an affordable level.
The telecommunications industry offers many solutions to meet metropolitan area needs. Several legacy services that we discuss in this chapter are available,but most fall short in meeting one or more of the objectives.The current trend is to fall back on the known and proven. Ethernet has long been the default LAN protocol but its range limitations have prevented it from spanning the metropolitan area. That is changing with modifications to the Ethernet MAC.
LEGACY MAN PROTOCOLS AND SERVICES
This section discusses the primary alternatives that are traditionally used for MAN service. We discussed SONET/SDH in Chapter 17 and with that background, will review its applications in the metropolitan area, and discuss the reasons it is less than ideal for multimedia communications. Fibre Channel is a broadband protocol that is optimized for SANs. FDDI is the most fully developed of the alternatives, but it is on the downward slope of its life cycle. SMDS is discussed because it is the LECs’ broadband vehicle and has reasonable availability in some areas. Two other protocols that are often used in the metropolitan area, frame relay and ATM, are mentioned here, and discussed at length in Chapters 34 and 35.
SONET/SDH
The LECs deploy SONET/SDH across their fiber-optic backbone, which makes it the default candidate for point-to-point service. Its main strength lies in the fact that it is universally available in LEC central offices, and is deployed in a dual-ring topology that makes it almost failure-proof. SONET/SDH nodes are designed to wrap
In a bidirectional line-switched ring (BLSR) traffic flows from node to node so bandwidth can be reused between any two nodes. In a unidirectional path-switched ring (UPSR) traffic circulates around the entire ring so bandwidth cannot be reused between nodes.
ATM can run over SONET/SDH to support multimedia traffic, but at a cost of greater complexity. Two less complex protocols are Packet over SONET (PoS) and Ethernet over SONET (EoS). PoS encapsulates IP packets in HDLC frames.This method has less overhead than ATM, but all traffic must be of the same general type. EoS strips away the Ethernet frame and encapsulates the payload in a Point-to-Point Protocol (PPP) frame.
This method preserves the Ethernet frame structure, which eliminates the need for converting from Ethernet to another protocol and back to Ethernet again. The fixed bandwidth of SONET/SDH results in wasted capacity with either method. An entire OC-24 (1244 Gbps), for example,is required to carry gigabit Ethernet.
SONET/SDH has two major disadvantages for MAN service. The first is the fact that fiber is not available everywhere a subscriber may need it. It is usually available in large buildings, but a distributed organization such as a bank is unlikely to find that fiber is available to all of its branches. The alternative is to use
The alternative is to use T1/E1 over copper to those branches, requiring a protocol conversion. The second drawback is its lack of scalability. The slowest SONET/SDH channel runs at 1.7 Mbps and the next higher increment jumps to 51.84 Mbps. Besides being expensive and rigid for the metropolitan area, with SONET/SDH either the network may be over-provisioned and under-utilized or it is a bottleneck.
Fibre Channel
Fibre Channel almost falls outside the definition of a telecommunications technology.
Its primary objective is to provide high-speed communications betweencomputers and peripherals, primarily mass storage. It was developed to replace Small Computer System Interface (SCSI) as a high-speed protocol for applications such as data backup, recovery, and mirroring. Fibre Channel is the predominate datalink technology used in SANs. The standard interfaces are 1GFC, 2GFC,4GFC, and 8GFC, with the number representing the speed in gigabits per second.
The 8GFC standard was approved in 2004, with products expected on the market
in the 2007–2008 period.Fibre Channel is designed around a five-layer protocol model that permits communication over shielded copper wire, coax, or fiber optics. The industry association coined the term “fibre” to encompass both optical fiber and copper
wire. Single-mode fiber can span 10 km. Multimode fiber with 62.5 μm core is limited to 1 km; 50 μm fiber can go twice that distance. Video coax and shielded twisted-pair wire can span 100 m. Copper wire is limited to 30 m.Fibre Channel connects devices through a switching fabric that supports interconnection of multiple devices. This makes it ideal for a campus environmentwhere several computers need to share access to multiple storage devices, printers, and other peripherals without being permanently and directly attached.
The protocol is not limited to switched connections, however. It also supports point-topoint,loop, and switched topologies as Figure 32-2 shows. In the arbitrated loop configuration up to 126 devices can be daisy-chained in a closed loop.The five-layer protocol is loosely based on the OSI model.
The bottom layer,FC-0 is the physical layer. FC-1 is the transmission protocol, which covers byte synchronization, serial encoding and decoding, and error control. Fibre Channel shares with gigabit Ethernet an 8B/10B coding scheme, which converts 8-bit
octets into 10-bit code groups. The 10-bit code groups must contain five ones and five zeros, four ones and six zeros, or six ones and four zeros. (F I G U R E 32-2)
The purpose is to maintain clock synchronization by ensuring high transition density and no long strings of 0s and 1s.
FC-2 defines the frame format and specifies how data is transferred between nodes. The protocol defines three classes of service. Class 1 is a connection-oriented switched circuit providing the equivalent of a dedicated connection. Class 2 is a connectionless service without guaranteed delivery, but with frame acknowledgement.Class 3 is a connectionless nonacknowledged datagram service. Layer 4, FC-3,handles some of the functions of the OSI transport and session layers, and severalfunctions that are not defined in OSI. One such function is striping, which enables multiple ports to operate in parallel to obtain additional bandwidth. The multicast function allows the same data to be sent to multiple destinations. The protocol also provides hunt groups, which enable incoming frames to hunt for an idle port.
FC-4 is the application layer, which provides buffering, synchronization, and prioritization of data. It also specifies methods for mapping Fibre Channel data to
other protocols such as IP, ATM’s AAL-5 (ATM adaptation layer 5), SCSI, and the
logical link protocol of IEEE 802.
Fiber Distributed Data Interface
FDDI is a 100 Mbps standard that operates on either fiber or copper. In 1990 when the FDDI protocol was approved, 100 Mbps was considered high speed.The protocol was intended as a LAN backbone, although it has enough speed and range to serve as a MAN.
With gigabit Ethernet and 10G Ethernet providing much greater bandwidth at lower cost, FDDI is now considered obsolescent, with applications largely limited to extending legacy networks.FDDI operates over counter-rotating token rings; one ring is designated as primary, and the other as secondary.
The primary ring carries data, while the secondary ring is in hot standby. With single-mode fiber, stations can be as far apart as 60 km and the network can span 200 km. FDDI can also ride on category 5 or higher UTP. The UTP application is sometimes called copper distributed data interface (CDDI), although the standard calls it twisted pair-physical medium dependent (TP-PMD). The FDDI standard specifies two classes of stations. Dual-attachment stations (DAS) connect to both rings, while single attachment stations (SAS) connect only to the primary ring through a wiring concentrator. Concentrators, which are FDDI devices that can support nonFDDI stations, can be single- or dual-attachment. The dual-ring appearance of DAS stations permits double the throughput since the station can send on both rings simultaneously, but the second ring is usually reserved for backup. The FDDI network supports three types of networks( Figure 32-3)
-Front-end networks. These are networks connecting workstations through a concentrator to a host computer or other peripherals over the FDDI network.
- Back-end networks. These allow connections from a host computer to peripherals such as high-speed disks and printers to be connected over FDDI to replace parallel bus connections.
- Backbone networks. These are connections between the main nodes on
The dual-ring architecture provides an effective measure of protection. If a link or a station fails, the stations go into an automatic bypass mode to route around the failure. Stations on either side of the break loop the primary ring to the secondary ring to form a single ring of twice the diameter.
FDDI operates much like 802.5 token ring except that multiple frames can circulate simultaneously on an FDDI network.
Other differences are the line-coding format and the dual-ring configuration of FDDI, while token ring supports only a single ring.
Switched Multimegabit Data Service
SMDS is a high-speed data service that LECs and others offer for linking applications
within a metropolitan area.The service can ride on ATM, although the initial designs used the IEEE 802.6 DQDB MAN protocol. DQDB is a ring protocol that uses a master control station.
If the master station fails, any station can assume the role.It operates on a counter-rotating ring and uses a unique method of reserving bandwidth. The master generates 125 μs frames, each containing a fixed number of time slots. Each node is equipped with a request counter and packet countdown.
When a node has a packet to send, it transmits a request upstream to the master. As the requests flow upstream, the nodes increment request counters and as time slots flow downstream, the nodes decrement their counters.
Each node,therefore, knows how many slots were requested and how many were filled bypassing slots intended for downstream nodes. If a node’s request counter is set at when the nth slot goes by its counter has reached zero so it can send on the next
empty slot.
SMDS is a service, the objective of which is to transport data with the any-toany
connectivity of telephone service. It is connectionless service, so unlike ATM or frame relay, there is no need to provision PVCs across the network. Both frame relay and ATM require PVCs for each pair of nodes, which makes them less economical than SMDS for full mesh connectivity.
Packets are variable-length datagrams with source and destination addresses, which enables them to be carried independently across the network. Most LECs charge a flat rate for a given amount of bandwidth, with no additional cost for distance or usage. SMDS speeds in the United States range from 1.5 to 34 Mbps, the latter being the effectivethroughput of SMDS over a T-3 access circuit.
SMDS nodes use globally unique E.164 addresses. The service provider maintains a database of addresses that are validated to communicate with receiving stations. Nonvalid attempts are blocked. Because of its connectionless protocol,the station can connect to any device that will accept the transmission.The principal application for SMDS is LAN interconnection, although it can be used for any data transport.
It is attractive for companies with multiple sites that are interconnected with T1/E1 or T3/E3. SMDS has had little impact on the metropolitan market, mainly because it has not been widely enough deployed. It is expensive for carriers to implement and user demand is fulfilled in other ways,principally frame relay.
METROPOLITAN AREA ETHERNET
Protocols to extend Ethernet into the metropolitan area have been developed and most observers believe Ethernet will become the dominant MAN protocol.The reasons for Ethernet’s popularity and its attractiveness in the MAN are easy to understand:
- Interface cards are installed on millions of computers worldwide.
- Many developers understand the protocol and it is robust and easy to implement.
- The end-to-end use of Ethernet eliminates the need to convert the LAN
to another protocol such as ATM, SONET/SDH, or frame relay and back
again.
- Service providers can build simple Ethernet networks over fiber without
SONET or ATM and provide low-cost service in the WAN.
-OAM&P is simple with Ethernet. Multiple services can accessed through a single user-to-network interface (UNI).
For these reasons plus the fact that legacy MAN protocols have multiple drawbacks, Ethernet in the first mile (EFM) is the dominant direction in the metropolitan network today.
The protocol has great promise because it extends technologies that many manufacturers support and users trust. It is not suitable for a MAN protocol without modification, however, because it lacks provisions for QoS and service providers cannot offer the guaranteed SLAs that customers demand.
Industry associations have developed extensions to the Ethernet protocol that permit itto operate outside the LAN. For Ethernet to be a viable carrier service it must include service attributes including a UNI, plus the capability of establishing virtual circuits and measuring service performance.
Gigabit Ethernet
From the datalink layer up, gigabit Ethernet uses the same 802.2 LLC as 10/100 Ethernet. The MAC is a scaled-up version of the CSMA/CD protocol used in 802.3 and operates in either half-duplex or full-duplex mode. Collisions aregenerally not at issue because the protocol is used in a switched environment.
For the physical layer gigabit Ethernet borrows the 8B/10B encoding of Fibre Channel. It supports four different media as shown in Table 32-1. The multimode standard supports both long- and short-wave lasers.
Only long-wave lasers,which span greater distances, are supported for single-mode. Multimode fiber is supported in both the 62.5 and 50 (m sizes, with the latter providing better performance.table(32-1)
SX, short-wave laser; LX, long-wave laser.Can extend to 10 km with long haul (LH) extension that is not part of the 802.3z standard.
The shielded twisted-pair wire option is designed for short-haul data center applications. The UTP standard uses all four pairs of category 5e cabling, and uses a different encoding scheme than fiber optics.Although gigabit Ethernet uses the same 8B/10B coding scheme as the
FC-1 in Fibre Channel, it operates at a slightly different baud rate. The FC-1 layer
receives octets from the FC-2 layer and maps them to a 10-bit pattern. This method
improves the ability of receiving devices to recover clocking from the transmitted
signal. Above the physical layer, gigabit Ethernet uses the standard 802.3 frame
format, which enables slower speed devices to communicate over gigabit Ethernet
without translation. The protocol provides a flow-control mechanism whereby a receiving station can send a frame to throttle back a sending station. Flow control
operates only in a point-to-point mode, not through a switch.
10G Ethernet
The 10G Ethernet protocol is a scaled-up version of the 10/100/1000 protocols. It can
be used in the backbone for aggregating slower links and it can be extended into the
wide area as well as the MAN. It uses the 802.3 MAC, frame format and frame size,
so it is an extension of the slower versions with two exceptions. First, it operates only
in full duplex so no collision detection and recovery is required. Second, except for
limited applications, 10G Ethernet operates only over fiber.
The fiber protocol is designed to interoperate with SONET/SDH. The objective is to provide an end-toend layer 2 transport without any reframing or protocol conversion.
The exception to the fiber-only medium is a copper protocol 802.3ak that was approved in 2004. That version operates over dual twinaxial cables and is intended primarily for data center use. Another standard proposed at the time of this writing is 802.3an. It is intended to support 10G Ethernet over UTP.
It can reach 55 m onexisting wiring. New wiring standards are needed to reach the 100-m range of category 5/6 wiring. Another task force is planning a standard 802.3aq for running 10G Ethernet over multimode fiber.10G Ethernet defines two physical (PHY) layers:
LAN and WAN. The WANPHY is an extension of the LAN PHY, adding a SONET/SDH framer. The OC-192 interface is close to 10 gigabits, but they do not match exactly. The WAN interface provides a payload of approximately 9.29 Gbps. The specification defines seven port types: 10GBase-LR, 10GBase-ER, 10GBase-SR, 10GBase-LW, 10GBase-ZR,10GBase-SW, and 10GBase-LX4. The copper specification adds an eighth interface,10GBase-CX4, and the proposed UTP standard would be 10GBase-T.
The supported ranges are:
-1310 nm serial PMD for single-mode fiber up to 10 km
-1550 nm serial PMD for single-mode fiber up to 40 km
- 850 nm serial PMD for multimode fiber up to 300 m
-1310 nm serial wide wave division multiplexing (WWDM) PMD forsingle-mode fiber up to 10 km or multimode up to 300 m
Ethernet in the First Mile
Some call it the first mile, some call it the last mile, and it is not even a mile at all, but just a metaphor for the link between users’ premises and the central office that has always been a bottleneck. Ethernet in the metropolitan area is not new.Several Ethernet-based CLECs entered the market shortly after passage of the
Telecommunications Act of 1996, but most failed in the technology downturn a few years later. The idea of extending Ethernet into the MAN is far from dead,however. In 2004, IEEE approved the EFM standard, 802.3ah.The EFM vision is broadband access with a universal end-to-end technology for both residential and business subscribers. The standard defines two classes of service.Ethernet line service (E-Line) is a point-to-point virtual connectionbetween two UNIs. Ethernet LAN (E-LAN) service offers multipoint connectivity.
An Ethernet virtual connection (EVC) is an association of two or more UNIs. The market for E-Line is to provide site-to-site connectivity. The service is used to create
private line services, Internet access, and point-to-point VPNs over the metropolitan
area. The purpose of E-LAN is to create multipoint VPNs and TLS, which makes the entire metropolitan network look like a single LAN without the need for protocol conversion. With E-LAN service, new VLAN members can be added without involving the service provider. In both versions, multiple services can be multiplexed on the same UNI.
The standard supports both fiber and copper media. Where fiber is available to a building, it is the best answer, but where it is not, the standard provides Ethernet over copper. The standard defines an operations, maintenance, and administration (OAM) process plus three technologies that are shown in Table 32-2.EFMP is a PON, which we discussed in Chapter 17.
The copper options encapsulate Ethernet over DSL with reduced distance and/or speed.
SHDSL is used forspeeds up to 10 Mbps or VDSL up to 2 Mbps within 2700 m. Unlike regular DSL,Ethernet over copper does not use ATM as the datalink protocol. The UNI is the standard 802.3 PHY, so the customer attachment can be a router or switch. The standard supports a variety of transport media including SONET/SDH, WDM, MPLS,
and resilient packet ring (RPR) plus two alternative encapsulation techniques that are designed to reduce the number of MAC addresses that must be retained in switch tables: MAC-in-MAC and Q-in-Q. The need for these is discussed later.The IEEE standards include provisions for prioritization, VLAN tagging,traffic shaping, bandwidth management, and resource reservation. The performance parameters include delay, jitter, and frame loss. The EFM standards do not include provisions for fault tolerance. That is included in the RPR standards, which we discuss in the next section, or Ethernet can be applied to SONET/SDH to take advantage of its fault tolerance.
The multipoint PON option, depicted in is particularly appealing for residential networks because the bandwidth of a fiber is so far in excess of residential needs. The fiber runs through passive splitters with a single strand delivered to subscribers, which share the
trunk fiber back to the central office.
VLAN Issues
When the LAN is extended to the metropolitan area, it takes on all of the characteristics of a LAN including some of the problems. One of these is the tendency of large networks to use a lot of bandwidth for broadcast and multicast traffic.The IEEE 802.1q VLAN protocol breaks large networks into smaller ones as a means of isolating broadcast traffic to VLAN members, which are recognized by port, MAC address, or IP address. (FIGURE32-5)
The VLAN members are identified by means of a 12-bit tag known as a Q-tag that is inserted in the Ethernet frame.
When VLANs are extended to the metropolitan area, the numbers of addresses they must retainin their tables can overwhelm the core switches. The two headquarters shown in Figure 32-6 could each have several thousand MAC addresses and the branch offices increase the total.
The switches in the core need to learn the MAC addresses of all the devices, resulting in huge tables. Eventually, the service can outstrip the switches’ table capacity.
Several methods have been proposed to resolve the issue by adding tags to frames as they cross the ingress edge node and stripping them off at the egress node. The tag frames are forwarded only to the end host of the VLAN the originator belongs to. The Q-in-Q encapsulation method inserts an additional Q-tag into the Ethernet frame at the ingress node. In the MAC-in-MAC method the ingress nodes insert two additional MAC address fields to identify the source and destination MAC addresses. With these methods, the core switch has to learn only the MAC addresses of the edge switches.
Resilient Packet Ring
The RPR protocol, standardized in 2004 as IEEE 802.17, provides the service protection and resilience of SONET/SDH, while retaining the simplicity of Ethernet.
RPR rings are dual counter-rotating rings that are optimized for data and designed to wrap around a ring failure in 50 ms or less. Unlike DQDB, the ring has no master
control node. The nodes negotiate for bandwidth based on a fairness algorithm
that is programmed into each node.
Each node is assigned a MAC address and can handle end-to-end or multicast traffic. The MAC protocol regulates access to the media and defines how the transmitting stations use the bandwidth. The RPR MAC has three service classes:
-Class A is a high rate CIR service. It supports guaranteed bandwidth,low latency, and circuit emulation. It is suitable for time-sensitive traffic such as voice and video.
- Class B is also a CIR service. Usage above the CIR, defined as excess
nformation rate (EIR) is subject to the fairness algorithm. It is intended for business data applications.
-Class C is best-effort traffic; for example, consumer Internet access. The nodes negotiate for a share of ring capacity for this class of traffic.
Figure 32-7 shows the architecture of RPR. All nodes have appearances on
dual counter-rotating rings. Each node has a topology map listing the location,
status, and capabilities of other nodes. The node uses the topology map to determine
the appropriate ring to use to reach the destination. When a node has permission
to send, it inserts a packet on the ring.
The MAC in the next downstream node determines whether to deliver it to its client or to forward it to the next station. Succeeding nodes forward the packet downstream until it either reaches the destination or exceeds the hop count limit. The destination node removes the packet from the ring.
The control units in the nodes participate in a fairness doctrine that ensures
smooth delivery of traffic below Class A, which is not affected by fairness control.
Class A traffic is subject to traffic shapers, which regulate large bursts.
Stations calculate the amount of bandwidth they are allowed to consume (defined as the fairrate) based on the traffic they receive from downstream stations, the bandwidth that their client is consuming, and the capacity of the ring.
The node calculates its fair rate by using the received fair rate and comparing it to its current usage. If a node determines that it is exceeding its fair rate, it reduces its fair rate value.
The MAC transmits traffic in class order. When class B and C traffic is delayed, it triggers the fairness algorithm to request more bandwidth. The node generates fairness control messages indicating bandwidth requirements and ring congestion.
The node considers itself congested when it cannot add the required amount of traffic to the ring.Each MAC broadcasts topology messages to other stations on the ring. From
these messages, each station creates its topology map.
The stations operate independently without a master station and have the capability of dynamically adding and removing stations. When a new station joins the ring, it broadcasts its topology message, which triggers the other nodes to send messages of their own. The station learns about its neighbors by noting which received messages have traveled only one hop.
RPR can work over multiple physical layers including SONET/SDH. Traffic
is sent in both directions on the ring to get maximum bandwidth utilization.
This is in contrast to other ring topologies that require traffic to traverse the entire ring
even though the destination is a ring neighbor. RPR sends the traffic directly to the
destination and keeps the rest of the ring open for use by other stations, a technique
known as spatial reuse.
MAN APPLICATION ISSUES
The metropolitan area network is in a state of transition as a result of customer
shifts toward a fully converged network.
When ATM was developed, it was expected to fill the backbone role and eventually migrate to the desktop, but its use is retarded by its complexity. Gigabit Ethernet, as a natural evolution of fast Ethernet, which managers already understand and trust, suffers from no such impediment. It can be shared, switched, and routed using the same topology as the slower speed products, which makes it the logical candidate for tomorrow’s MAN.
That change will be evolutionary, with metropolitan Ethernet gradually replacing other services.The Ethernet MAN standards have not been in place long enough to see the
outcome, but if history is any indication, prices will drop and demand will thrive as
the protocol breaks its previous bounds.
Most metropolitan areas have huge amounts of undeveloped fiber because of the building frenzy that followed passage of the 1996 legislation, but most of it serves the same high-density business district, leaving the rest served only with copper cable.
Ethernet is a good alternative for data applications in those buildings that are served by fiber optics.Demand for fixed-bandwidth circuits will continue well into the future. This
need is adequately filled by SONET/SDH and the ILEC networks have ample capacity in place.
The EFM standards coupled with RPR service protection can supplement SONET/SDH for a time, and will probably replace it at lower cost wherever fiber is available. The lack of fiber optics to homes and smaller commercial buildings means that T1/E1 will be around for many years, which in turn means that the all-Ethernet network for most companies will be years in the future.
The key to serving the metropolitan area in the future appears to be development
of the multipoint alternative of the EFM standards.The copper alternatives are a stopgap. Although end-to-end Ethernet can be implemented over copper, that is the only real advantage of EFMC over DSL.
To gain the minimum Ethernet wire speed of 10 Mbps means placing copper nodes within 750 m of the served subscribers and that will require major rebuilding of the copper cable network. Of the technologies discussed in this chapter, Ethernet has the brightest outlook for serving the MAN, but it is likely to come on gradually.
The ILECs will serve the easy places first: that is the locations served with fiber already. They will also probably expand the fiber optics network by implementing PONs. Fiber provides more capacity than gigabit Ethernet can use, which will probably mean that 10G Ethernet will dominate in the MAN backbone.
Fibre Channel
Fibre Channel is designed for linking high-speed devices in a campus environment
and that appears to be the market it will serve.
Its switching capability enables it to create exclusive nonshared channels between devices for the duration of a session,which has always been the main benefit of the PSTN for low-speed applications.
While Fibre Channel could fulfill some of the same functions as SMDS, it is not designed with the data security provisions that would make it suitable as a public protocol. Furthermore, to apply it in the metropolitan environment as a private network would mean obtaining dark fiber, which is not readily available except to common carriers.
Fiber Distributed Data Interface
FDDI was widely used for linking LAN segments through routers in the past, but its heyday, like its token ring cousin, is past. As Ethernet standards developed, the price dropped, and FDDI was no longer economical. It has higher throughput than fast Ethernet, but at higher cost. In the backbone it cannot compete with gigabit Ethernet, the price of which has fallen. FDDI will still be used in legacy network backbones for several more years, but it is not a good candidate for new network development.
Switched Multimegabit Data Service
As a LAN interconnection service, which is its primary use, SMDS has attractive
aspects, but it is likely to disappear as the ILECs implement metropolitan Ethernet
and RPR. In many regions the ILECs have not pushed SMDS because it serves
much of the same market as frame relay, which is more widely accepted. The main
advantage SMDS has over frame relay is its any-to-any connectivity without defining PVCs. In most enterprise networks, however, remote sites communicate mainly with headquarters, so site-to-site PVCs are unnecessary. That will change as multimedia applications gravitate to IP, which results in the central site becoming a choke point. SMDS is a more static configuration than Ethernet and its E.164 addressing scheme is less effective than Ethernet for such traffic.
The telecommunications industry categorizes networks as local, metropolitan,and wide area or global. The distinction between WAN and MAN is vague because many of the same protocols and services are used without regard to the span ofthe network.
A MAN is a public network that bridges LAN and WAN, typically covering a span of 5 to 50 km. The area is roughly the size of a city, and in larger metropolitan areas multiple providers offer MAN services.
A MAN has many of the same characteristics as a WAN, and shares some of the same aplication. It could be considered simply as a scaled-down version of the WAN, but many of its requirements are distinctly different.
MAN technologies are borrowed from both the LAN and WAN and work primarily at the datalink layer. MAN services are delivered over fiber optics if possible, but copper and wireless alternatives also exist.
Legacy technologies used for MANs include frame relay, ATM, Fiber Distributed Data Interface (FDDI), Fibre Channel, Distributed Queue Dual Bus (DQDB), and Switched Multimegabit Data Service (SMDS). Newer networks work over gigabit and 10G Ethernet applied directly to fiber and some of the wireless technologies we discussed in Chapter 21. Besides point-to-point circuits riding on various levels of TDM, The ILECs offer frame relay with bandwidths of up to DS-3. The ILECs’ frame relay networks generally span a LATA which, depending on the territory,
may encompass a metropolitan area or an entire state. The following are typical applications for a MAN:
- LAN-to-LAN connectivity—sometimes called transparent LAN service
(TLS)
- Storage area networks (SANs)
- Telemedicine
- Delay-sensitive data such as VoIP and video conferencing
- Low bit-rate synchronous and asynchronous data such as telemetry
and alarm services
- WAN access services
- High bit-rate data such as video-on-demand
- Traditional data and voice leased-line services
None of the legacy protocols is a good match for all of these applications,several of which are bursty. Conventional networks, usually provisioned over SONET/SDH are composed of fixed-bandwidth circuits that are optimized for voice, but do not scale well for data. Fixed-bandwidth circuits are acceptable for many applications, but emerging services have a high ratio of peak-to-average data flow.
For example, a physician examining an x-ray may need to move 10 megabits or more of data while the image downloads to the display, but then demand drops to zero.
Dedicated facilities are satisfactory for data applications that have reasonably
constant bandwidth requirements. If the load is predictable, fixed-bandwidth circuits are satisfactory, provided they terminate at a single destination. If the bandwidth requirements are variable, the user pays a penalty, either in slow response during high-demand periods, or in wasted circuit time during lowdemand periods. Furthermore, the provisioning interval for changing or rearranging circuits is lengthy and costly and cannot respond quickly to changing applications.
MANs must meet a set of conditions, many of which are unique to the metropolitan area:
- Provide high reliability equivalent to that provided by SONET/SDH rings with fast failover in case of disruption.
-Deliver bandwidth on demand in simple increments that are readily configurable.
-Offer simple and fast provisioning.
- Offer tiered services with traffic classified and segmented on a per-user or per-flow basis.
-Provide SLAs with guaranteed latency, jitter, and packet loss.
- Enforce policy. If a customer signs up for a particular level of service,police traffic to ensure that the network provides that level and no more.
- Provide end-to-end security. Users’ packets must be isolated from other users.
- Provide usage-based billing.
- Make efficient use of the fiber-optic infrastructure, while holding costs to an affordable level.
The telecommunications industry offers many solutions to meet metropolitan area needs. Several legacy services that we discuss in this chapter are available,but most fall short in meeting one or more of the objectives.The current trend is to fall back on the known and proven. Ethernet has long been the default LAN protocol but its range limitations have prevented it from spanning the metropolitan area. That is changing with modifications to the Ethernet MAC.
LEGACY MAN PROTOCOLS AND SERVICES
This section discusses the primary alternatives that are traditionally used for MAN service. We discussed SONET/SDH in Chapter 17 and with that background, will review its applications in the metropolitan area, and discuss the reasons it is less than ideal for multimedia communications. Fibre Channel is a broadband protocol that is optimized for SANs. FDDI is the most fully developed of the alternatives, but it is on the downward slope of its life cycle. SMDS is discussed because it is the LECs’ broadband vehicle and has reasonable availability in some areas. Two other protocols that are often used in the metropolitan area, frame relay and ATM, are mentioned here, and discussed at length in Chapters 34 and 35.
SONET/SDH
The LECs deploy SONET/SDH across their fiber-optic backbone, which makes it the default candidate for point-to-point service. Its main strength lies in the fact that it is universally available in LEC central offices, and is deployed in a dual-ring topology that makes it almost failure-proof. SONET/SDH nodes are designed to wrap
In a bidirectional line-switched ring (BLSR) traffic flows from node to node so bandwidth can be reused between any two nodes. In a unidirectional path-switched ring (UPSR) traffic circulates around the entire ring so bandwidth cannot be reused between nodes.
ATM can run over SONET/SDH to support multimedia traffic, but at a cost of greater complexity. Two less complex protocols are Packet over SONET (PoS) and Ethernet over SONET (EoS). PoS encapsulates IP packets in HDLC frames.This method has less overhead than ATM, but all traffic must be of the same general type. EoS strips away the Ethernet frame and encapsulates the payload in a Point-to-Point Protocol (PPP) frame.
This method preserves the Ethernet frame structure, which eliminates the need for converting from Ethernet to another protocol and back to Ethernet again. The fixed bandwidth of SONET/SDH results in wasted capacity with either method. An entire OC-24 (1244 Gbps), for example,is required to carry gigabit Ethernet.
SONET/SDH has two major disadvantages for MAN service. The first is the fact that fiber is not available everywhere a subscriber may need it. It is usually available in large buildings, but a distributed organization such as a bank is unlikely to find that fiber is available to all of its branches. The alternative is to use
The alternative is to use T1/E1 over copper to those branches, requiring a protocol conversion. The second drawback is its lack of scalability. The slowest SONET/SDH channel runs at 1.7 Mbps and the next higher increment jumps to 51.84 Mbps. Besides being expensive and rigid for the metropolitan area, with SONET/SDH either the network may be over-provisioned and under-utilized or it is a bottleneck.
Fibre Channel
Fibre Channel almost falls outside the definition of a telecommunications technology.
Its primary objective is to provide high-speed communications betweencomputers and peripherals, primarily mass storage. It was developed to replace Small Computer System Interface (SCSI) as a high-speed protocol for applications such as data backup, recovery, and mirroring. Fibre Channel is the predominate datalink technology used in SANs. The standard interfaces are 1GFC, 2GFC,4GFC, and 8GFC, with the number representing the speed in gigabits per second.
The 8GFC standard was approved in 2004, with products expected on the market
in the 2007–2008 period.Fibre Channel is designed around a five-layer protocol model that permits communication over shielded copper wire, coax, or fiber optics. The industry association coined the term “fibre” to encompass both optical fiber and copper
wire. Single-mode fiber can span 10 km. Multimode fiber with 62.5 μm core is limited to 1 km; 50 μm fiber can go twice that distance. Video coax and shielded twisted-pair wire can span 100 m. Copper wire is limited to 30 m.Fibre Channel connects devices through a switching fabric that supports interconnection of multiple devices. This makes it ideal for a campus environmentwhere several computers need to share access to multiple storage devices, printers, and other peripherals without being permanently and directly attached.
The protocol is not limited to switched connections, however. It also supports point-topoint,loop, and switched topologies as Figure 32-2 shows. In the arbitrated loop configuration up to 126 devices can be daisy-chained in a closed loop.The five-layer protocol is loosely based on the OSI model.
The bottom layer,FC-0 is the physical layer. FC-1 is the transmission protocol, which covers byte synchronization, serial encoding and decoding, and error control. Fibre Channel shares with gigabit Ethernet an 8B/10B coding scheme, which converts 8-bit
octets into 10-bit code groups. The 10-bit code groups must contain five ones and five zeros, four ones and six zeros, or six ones and four zeros. (F I G U R E 32-2)
The purpose is to maintain clock synchronization by ensuring high transition density and no long strings of 0s and 1s.
FC-2 defines the frame format and specifies how data is transferred between nodes. The protocol defines three classes of service. Class 1 is a connection-oriented switched circuit providing the equivalent of a dedicated connection. Class 2 is a connectionless service without guaranteed delivery, but with frame acknowledgement.Class 3 is a connectionless nonacknowledged datagram service. Layer 4, FC-3,handles some of the functions of the OSI transport and session layers, and severalfunctions that are not defined in OSI. One such function is striping, which enables multiple ports to operate in parallel to obtain additional bandwidth. The multicast function allows the same data to be sent to multiple destinations. The protocol also provides hunt groups, which enable incoming frames to hunt for an idle port.
FC-4 is the application layer, which provides buffering, synchronization, and prioritization of data. It also specifies methods for mapping Fibre Channel data to
other protocols such as IP, ATM’s AAL-5 (ATM adaptation layer 5), SCSI, and the
logical link protocol of IEEE 802.
Fiber Distributed Data Interface
FDDI is a 100 Mbps standard that operates on either fiber or copper. In 1990 when the FDDI protocol was approved, 100 Mbps was considered high speed.The protocol was intended as a LAN backbone, although it has enough speed and range to serve as a MAN.
With gigabit Ethernet and 10G Ethernet providing much greater bandwidth at lower cost, FDDI is now considered obsolescent, with applications largely limited to extending legacy networks.FDDI operates over counter-rotating token rings; one ring is designated as primary, and the other as secondary.
The primary ring carries data, while the secondary ring is in hot standby. With single-mode fiber, stations can be as far apart as 60 km and the network can span 200 km. FDDI can also ride on category 5 or higher UTP. The UTP application is sometimes called copper distributed data interface (CDDI), although the standard calls it twisted pair-physical medium dependent (TP-PMD). The FDDI standard specifies two classes of stations. Dual-attachment stations (DAS) connect to both rings, while single attachment stations (SAS) connect only to the primary ring through a wiring concentrator. Concentrators, which are FDDI devices that can support nonFDDI stations, can be single- or dual-attachment. The dual-ring appearance of DAS stations permits double the throughput since the station can send on both rings simultaneously, but the second ring is usually reserved for backup. The FDDI network supports three types of networks( Figure 32-3)
-Front-end networks. These are networks connecting workstations through a concentrator to a host computer or other peripherals over the FDDI network.
- Back-end networks. These allow connections from a host computer to peripherals such as high-speed disks and printers to be connected over FDDI to replace parallel bus connections.
- Backbone networks. These are connections between the main nodes on
The dual-ring architecture provides an effective measure of protection. If a link or a station fails, the stations go into an automatic bypass mode to route around the failure. Stations on either side of the break loop the primary ring to the secondary ring to form a single ring of twice the diameter.
FDDI operates much like 802.5 token ring except that multiple frames can circulate simultaneously on an FDDI network.
Other differences are the line-coding format and the dual-ring configuration of FDDI, while token ring supports only a single ring.
Switched Multimegabit Data Service
SMDS is a high-speed data service that LECs and others offer for linking applications
within a metropolitan area.The service can ride on ATM, although the initial designs used the IEEE 802.6 DQDB MAN protocol. DQDB is a ring protocol that uses a master control station.
If the master station fails, any station can assume the role.It operates on a counter-rotating ring and uses a unique method of reserving bandwidth. The master generates 125 μs frames, each containing a fixed number of time slots. Each node is equipped with a request counter and packet countdown.
When a node has a packet to send, it transmits a request upstream to the master. As the requests flow upstream, the nodes increment request counters and as time slots flow downstream, the nodes decrement their counters.
Each node,therefore, knows how many slots were requested and how many were filled bypassing slots intended for downstream nodes. If a node’s request counter is set at when the nth slot goes by its counter has reached zero so it can send on the next
empty slot.
SMDS is a service, the objective of which is to transport data with the any-toany
connectivity of telephone service. It is connectionless service, so unlike ATM or frame relay, there is no need to provision PVCs across the network. Both frame relay and ATM require PVCs for each pair of nodes, which makes them less economical than SMDS for full mesh connectivity.
Packets are variable-length datagrams with source and destination addresses, which enables them to be carried independently across the network. Most LECs charge a flat rate for a given amount of bandwidth, with no additional cost for distance or usage. SMDS speeds in the United States range from 1.5 to 34 Mbps, the latter being the effectivethroughput of SMDS over a T-3 access circuit.
SMDS nodes use globally unique E.164 addresses. The service provider maintains a database of addresses that are validated to communicate with receiving stations. Nonvalid attempts are blocked. Because of its connectionless protocol,the station can connect to any device that will accept the transmission.The principal application for SMDS is LAN interconnection, although it can be used for any data transport.
It is attractive for companies with multiple sites that are interconnected with T1/E1 or T3/E3. SMDS has had little impact on the metropolitan market, mainly because it has not been widely enough deployed. It is expensive for carriers to implement and user demand is fulfilled in other ways,principally frame relay.
METROPOLITAN AREA ETHERNET
Protocols to extend Ethernet into the metropolitan area have been developed and most observers believe Ethernet will become the dominant MAN protocol.The reasons for Ethernet’s popularity and its attractiveness in the MAN are easy to understand:
- Interface cards are installed on millions of computers worldwide.
- Many developers understand the protocol and it is robust and easy to implement.
- The end-to-end use of Ethernet eliminates the need to convert the LAN
to another protocol such as ATM, SONET/SDH, or frame relay and back
again.
- Service providers can build simple Ethernet networks over fiber without
SONET or ATM and provide low-cost service in the WAN.
-OAM&P is simple with Ethernet. Multiple services can accessed through a single user-to-network interface (UNI).
For these reasons plus the fact that legacy MAN protocols have multiple drawbacks, Ethernet in the first mile (EFM) is the dominant direction in the metropolitan network today.
The protocol has great promise because it extends technologies that many manufacturers support and users trust. It is not suitable for a MAN protocol without modification, however, because it lacks provisions for QoS and service providers cannot offer the guaranteed SLAs that customers demand.
Industry associations have developed extensions to the Ethernet protocol that permit itto operate outside the LAN. For Ethernet to be a viable carrier service it must include service attributes including a UNI, plus the capability of establishing virtual circuits and measuring service performance.
Gigabit Ethernet
From the datalink layer up, gigabit Ethernet uses the same 802.2 LLC as 10/100 Ethernet. The MAC is a scaled-up version of the CSMA/CD protocol used in 802.3 and operates in either half-duplex or full-duplex mode. Collisions aregenerally not at issue because the protocol is used in a switched environment.
For the physical layer gigabit Ethernet borrows the 8B/10B encoding of Fibre Channel. It supports four different media as shown in Table 32-1. The multimode standard supports both long- and short-wave lasers.
Only long-wave lasers,which span greater distances, are supported for single-mode. Multimode fiber is supported in both the 62.5 and 50 (m sizes, with the latter providing better performance.table(32-1)
SX, short-wave laser; LX, long-wave laser.Can extend to 10 km with long haul (LH) extension that is not part of the 802.3z standard.
The shielded twisted-pair wire option is designed for short-haul data center applications. The UTP standard uses all four pairs of category 5e cabling, and uses a different encoding scheme than fiber optics.Although gigabit Ethernet uses the same 8B/10B coding scheme as the
FC-1 in Fibre Channel, it operates at a slightly different baud rate. The FC-1 layer
receives octets from the FC-2 layer and maps them to a 10-bit pattern. This method
improves the ability of receiving devices to recover clocking from the transmitted
signal. Above the physical layer, gigabit Ethernet uses the standard 802.3 frame
format, which enables slower speed devices to communicate over gigabit Ethernet
without translation. The protocol provides a flow-control mechanism whereby a receiving station can send a frame to throttle back a sending station. Flow control
operates only in a point-to-point mode, not through a switch.
10G Ethernet
The 10G Ethernet protocol is a scaled-up version of the 10/100/1000 protocols. It can
be used in the backbone for aggregating slower links and it can be extended into the
wide area as well as the MAN. It uses the 802.3 MAC, frame format and frame size,
so it is an extension of the slower versions with two exceptions. First, it operates only
in full duplex so no collision detection and recovery is required. Second, except for
limited applications, 10G Ethernet operates only over fiber.
The fiber protocol is designed to interoperate with SONET/SDH. The objective is to provide an end-toend layer 2 transport without any reframing or protocol conversion.
The exception to the fiber-only medium is a copper protocol 802.3ak that was approved in 2004. That version operates over dual twinaxial cables and is intended primarily for data center use. Another standard proposed at the time of this writing is 802.3an. It is intended to support 10G Ethernet over UTP.
It can reach 55 m onexisting wiring. New wiring standards are needed to reach the 100-m range of category 5/6 wiring. Another task force is planning a standard 802.3aq for running 10G Ethernet over multimode fiber.10G Ethernet defines two physical (PHY) layers:
LAN and WAN. The WANPHY is an extension of the LAN PHY, adding a SONET/SDH framer. The OC-192 interface is close to 10 gigabits, but they do not match exactly. The WAN interface provides a payload of approximately 9.29 Gbps. The specification defines seven port types: 10GBase-LR, 10GBase-ER, 10GBase-SR, 10GBase-LW, 10GBase-ZR,10GBase-SW, and 10GBase-LX4. The copper specification adds an eighth interface,10GBase-CX4, and the proposed UTP standard would be 10GBase-T.
The supported ranges are:
-1310 nm serial PMD for single-mode fiber up to 10 km
-1550 nm serial PMD for single-mode fiber up to 40 km
- 850 nm serial PMD for multimode fiber up to 300 m
-1310 nm serial wide wave division multiplexing (WWDM) PMD forsingle-mode fiber up to 10 km or multimode up to 300 m
Ethernet in the First Mile
Some call it the first mile, some call it the last mile, and it is not even a mile at all, but just a metaphor for the link between users’ premises and the central office that has always been a bottleneck. Ethernet in the metropolitan area is not new.Several Ethernet-based CLECs entered the market shortly after passage of the
Telecommunications Act of 1996, but most failed in the technology downturn a few years later. The idea of extending Ethernet into the MAN is far from dead,however. In 2004, IEEE approved the EFM standard, 802.3ah.The EFM vision is broadband access with a universal end-to-end technology for both residential and business subscribers. The standard defines two classes of service.Ethernet line service (E-Line) is a point-to-point virtual connectionbetween two UNIs. Ethernet LAN (E-LAN) service offers multipoint connectivity.
An Ethernet virtual connection (EVC) is an association of two or more UNIs. The market for E-Line is to provide site-to-site connectivity. The service is used to create
private line services, Internet access, and point-to-point VPNs over the metropolitan
area. The purpose of E-LAN is to create multipoint VPNs and TLS, which makes the entire metropolitan network look like a single LAN without the need for protocol conversion. With E-LAN service, new VLAN members can be added without involving the service provider. In both versions, multiple services can be multiplexed on the same UNI.
The standard supports both fiber and copper media. Where fiber is available to a building, it is the best answer, but where it is not, the standard provides Ethernet over copper. The standard defines an operations, maintenance, and administration (OAM) process plus three technologies that are shown in Table 32-2.EFMP is a PON, which we discussed in Chapter 17.
The copper options encapsulate Ethernet over DSL with reduced distance and/or speed.
SHDSL is used forspeeds up to 10 Mbps or VDSL up to 2 Mbps within 2700 m. Unlike regular DSL,Ethernet over copper does not use ATM as the datalink protocol. The UNI is the standard 802.3 PHY, so the customer attachment can be a router or switch. The standard supports a variety of transport media including SONET/SDH, WDM, MPLS,
and resilient packet ring (RPR) plus two alternative encapsulation techniques that are designed to reduce the number of MAC addresses that must be retained in switch tables: MAC-in-MAC and Q-in-Q. The need for these is discussed later.The IEEE standards include provisions for prioritization, VLAN tagging,traffic shaping, bandwidth management, and resource reservation. The performance parameters include delay, jitter, and frame loss. The EFM standards do not include provisions for fault tolerance. That is included in the RPR standards, which we discuss in the next section, or Ethernet can be applied to SONET/SDH to take advantage of its fault tolerance.
The multipoint PON option, depicted in is particularly appealing for residential networks because the bandwidth of a fiber is so far in excess of residential needs. The fiber runs through passive splitters with a single strand delivered to subscribers, which share the
trunk fiber back to the central office.
VLAN Issues
When the LAN is extended to the metropolitan area, it takes on all of the characteristics of a LAN including some of the problems. One of these is the tendency of large networks to use a lot of bandwidth for broadcast and multicast traffic.The IEEE 802.1q VLAN protocol breaks large networks into smaller ones as a means of isolating broadcast traffic to VLAN members, which are recognized by port, MAC address, or IP address. (FIGURE32-5)
The VLAN members are identified by means of a 12-bit tag known as a Q-tag that is inserted in the Ethernet frame.
When VLANs are extended to the metropolitan area, the numbers of addresses they must retainin their tables can overwhelm the core switches. The two headquarters shown in Figure 32-6 could each have several thousand MAC addresses and the branch offices increase the total.
The switches in the core need to learn the MAC addresses of all the devices, resulting in huge tables. Eventually, the service can outstrip the switches’ table capacity.
Several methods have been proposed to resolve the issue by adding tags to frames as they cross the ingress edge node and stripping them off at the egress node. The tag frames are forwarded only to the end host of the VLAN the originator belongs to. The Q-in-Q encapsulation method inserts an additional Q-tag into the Ethernet frame at the ingress node. In the MAC-in-MAC method the ingress nodes insert two additional MAC address fields to identify the source and destination MAC addresses. With these methods, the core switch has to learn only the MAC addresses of the edge switches.
Resilient Packet Ring
The RPR protocol, standardized in 2004 as IEEE 802.17, provides the service protection and resilience of SONET/SDH, while retaining the simplicity of Ethernet.
RPR rings are dual counter-rotating rings that are optimized for data and designed to wrap around a ring failure in 50 ms or less. Unlike DQDB, the ring has no master
control node. The nodes negotiate for bandwidth based on a fairness algorithm
that is programmed into each node.
Each node is assigned a MAC address and can handle end-to-end or multicast traffic. The MAC protocol regulates access to the media and defines how the transmitting stations use the bandwidth. The RPR MAC has three service classes:
-Class A is a high rate CIR service. It supports guaranteed bandwidth,low latency, and circuit emulation. It is suitable for time-sensitive traffic such as voice and video.
- Class B is also a CIR service. Usage above the CIR, defined as excess
nformation rate (EIR) is subject to the fairness algorithm. It is intended for business data applications.
-Class C is best-effort traffic; for example, consumer Internet access. The nodes negotiate for a share of ring capacity for this class of traffic.
Figure 32-7 shows the architecture of RPR. All nodes have appearances on
dual counter-rotating rings. Each node has a topology map listing the location,
status, and capabilities of other nodes. The node uses the topology map to determine
the appropriate ring to use to reach the destination. When a node has permission
to send, it inserts a packet on the ring.
The MAC in the next downstream node determines whether to deliver it to its client or to forward it to the next station. Succeeding nodes forward the packet downstream until it either reaches the destination or exceeds the hop count limit. The destination node removes the packet from the ring.
The control units in the nodes participate in a fairness doctrine that ensures
smooth delivery of traffic below Class A, which is not affected by fairness control.
Class A traffic is subject to traffic shapers, which regulate large bursts.
Stations calculate the amount of bandwidth they are allowed to consume (defined as the fairrate) based on the traffic they receive from downstream stations, the bandwidth that their client is consuming, and the capacity of the ring.
The node calculates its fair rate by using the received fair rate and comparing it to its current usage. If a node determines that it is exceeding its fair rate, it reduces its fair rate value.
The MAC transmits traffic in class order. When class B and C traffic is delayed, it triggers the fairness algorithm to request more bandwidth. The node generates fairness control messages indicating bandwidth requirements and ring congestion.
The node considers itself congested when it cannot add the required amount of traffic to the ring.Each MAC broadcasts topology messages to other stations on the ring. From
these messages, each station creates its topology map.
The stations operate independently without a master station and have the capability of dynamically adding and removing stations. When a new station joins the ring, it broadcasts its topology message, which triggers the other nodes to send messages of their own. The station learns about its neighbors by noting which received messages have traveled only one hop.
RPR can work over multiple physical layers including SONET/SDH. Traffic
is sent in both directions on the ring to get maximum bandwidth utilization.
This is in contrast to other ring topologies that require traffic to traverse the entire ring
even though the destination is a ring neighbor. RPR sends the traffic directly to the
destination and keeps the rest of the ring open for use by other stations, a technique
known as spatial reuse.
MAN APPLICATION ISSUES
The metropolitan area network is in a state of transition as a result of customer
shifts toward a fully converged network.
When ATM was developed, it was expected to fill the backbone role and eventually migrate to the desktop, but its use is retarded by its complexity. Gigabit Ethernet, as a natural evolution of fast Ethernet, which managers already understand and trust, suffers from no such impediment. It can be shared, switched, and routed using the same topology as the slower speed products, which makes it the logical candidate for tomorrow’s MAN.
That change will be evolutionary, with metropolitan Ethernet gradually replacing other services.The Ethernet MAN standards have not been in place long enough to see the
outcome, but if history is any indication, prices will drop and demand will thrive as
the protocol breaks its previous bounds.
Most metropolitan areas have huge amounts of undeveloped fiber because of the building frenzy that followed passage of the 1996 legislation, but most of it serves the same high-density business district, leaving the rest served only with copper cable.
Ethernet is a good alternative for data applications in those buildings that are served by fiber optics.Demand for fixed-bandwidth circuits will continue well into the future. This
need is adequately filled by SONET/SDH and the ILEC networks have ample capacity in place.
The EFM standards coupled with RPR service protection can supplement SONET/SDH for a time, and will probably replace it at lower cost wherever fiber is available. The lack of fiber optics to homes and smaller commercial buildings means that T1/E1 will be around for many years, which in turn means that the all-Ethernet network for most companies will be years in the future.
The key to serving the metropolitan area in the future appears to be development
of the multipoint alternative of the EFM standards.The copper alternatives are a stopgap. Although end-to-end Ethernet can be implemented over copper, that is the only real advantage of EFMC over DSL.
To gain the minimum Ethernet wire speed of 10 Mbps means placing copper nodes within 750 m of the served subscribers and that will require major rebuilding of the copper cable network. Of the technologies discussed in this chapter, Ethernet has the brightest outlook for serving the MAN, but it is likely to come on gradually.
The ILECs will serve the easy places first: that is the locations served with fiber already. They will also probably expand the fiber optics network by implementing PONs. Fiber provides more capacity than gigabit Ethernet can use, which will probably mean that 10G Ethernet will dominate in the MAN backbone.
Fibre Channel
Fibre Channel is designed for linking high-speed devices in a campus environment
and that appears to be the market it will serve.
Its switching capability enables it to create exclusive nonshared channels between devices for the duration of a session,which has always been the main benefit of the PSTN for low-speed applications.
While Fibre Channel could fulfill some of the same functions as SMDS, it is not designed with the data security provisions that would make it suitable as a public protocol. Furthermore, to apply it in the metropolitan environment as a private network would mean obtaining dark fiber, which is not readily available except to common carriers.
Fiber Distributed Data Interface
FDDI was widely used for linking LAN segments through routers in the past, but its heyday, like its token ring cousin, is past. As Ethernet standards developed, the price dropped, and FDDI was no longer economical. It has higher throughput than fast Ethernet, but at higher cost. In the backbone it cannot compete with gigabit Ethernet, the price of which has fallen. FDDI will still be used in legacy network backbones for several more years, but it is not a good candidate for new network development.
Switched Multimegabit Data Service
As a LAN interconnection service, which is its primary use, SMDS has attractive
aspects, but it is likely to disappear as the ILECs implement metropolitan Ethernet
and RPR. In many regions the ILECs have not pushed SMDS because it serves
much of the same market as frame relay, which is more widely accepted. The main
advantage SMDS has over frame relay is its any-to-any connectivity without defining PVCs. In most enterprise networks, however, remote sites communicate mainly with headquarters, so site-to-site PVCs are unnecessary. That will change as multimedia applications gravitate to IP, which results in the central site becoming a choke point. SMDS is a more static configuration than Ethernet and its E.164 addressing scheme is less effective than Ethernet for such traffic.
Tuesday, September 28, 2010
bayarmaa82@gmail.com
Ажилд шалгаруулж авна
Талх чихэр ХК
1.Захиралын туслах- 1хүн
Тавигдах шаардлага:
-Гадаад харилцааны чиглэлээр гадаад дотоодын их,дээд сургууль төгссөн,баклавар болон түүнээс дээш зэрэгтэй байх
-Англи,Орос ярианы болон бичгийн хэлийг мэргэжлийн өндөр түвшинд эзэмшсэн байх
-Гадаад хэл дээр бичиг баримт боловсруулах чадвартай байх
-Харилцааны соёл мэргэжлийн ёс зүйтэй байх
-Компьютерийн хэрэглээний программуудыг бүрэн эзэмшсэн байх
- Ажлын дадлага туршлагатай мэргэжлээрээ 3-аас доошгүй жил ажилласан байх
- Идэвх санаачлагатай хувийн зохион байгуулалт сайтай байх
2.Маркетингийн менежер-2 хүн
Тавигдах шаардлага:
-Бизнесийн удирдлага болон менежментийн чиглэлээр гадаад дотоодын их дээд сургууль төгссөн баклавар болон түүнээс дээш зэрэгтэй байх
- Англи,Орос хэлний дундаас дээш түвшний мэдлэгтэй байх
- Ажлын дадлага туршлагатай мэргэжлээрээ 3-аас доошгүй жил ажилласан байх
-Компьютерийн хэрэглээний программуудыг бүрэн эзэмшсэн байх
-Баримт бичиг төлөвлөх боловсруулах судалгаа шинжилгээ хийж дүгнэлт гаргах чадвартай
-Илтгэх ур чадвар сайтай харилцааны өндөр соёлтой
-Ажлын ачаалал дааж бие даан болон багаар хамтран ажиллах чадвартай
- Идэвх санаачлагатай хувийн зохион байгуулалт сайтай байх
Бүрдүүлэх материал:
-Ажилд орохыг хүсэгчийн анкет/байгуулга дээр ирж бөглөх/
-Диплом мэргэжлийн үнэмлэх сертификат түүний хуулбар
-Иргэний үнэмлэх түүний хуулбар
-2 хувь цээж зураг
-Оршин суугаа газрын тодорхойлолт
-Цагдаагийн газрын тодорхойлолт
Хаяг:Улаанбаатар хот СХД 18-р хороо’’Талх Чихэр’’ХК-ийн байр
Холбоо барих утас:11-631526,93220222
Vacancy announcement
1.Assistant to CEO
Requirements:
-Must have Bachelor degree in International Business Communication or more of foriegn or local university
-High level of speaking and writing skill of English and Russian
-Ability of work with documents in foreign language
-Social skill, professional ethic
-Knowledge of computer applications
-3 or more years experience of working
-Be creative, active
2.Manager of Marketing
Requirements:
-Must have Bachelor degree in Business Administration or Management, or more of foriegn or local university
-Intermediate or more English and Russian language skill
-3 or more years experience of working
-Knowledge of computer applications
-Ability of work with documents, research with them
-Social skill, Lecture skill
-Be creative, active
Required items:
-Application /take it from company/
-Diploma, Certificate or copy of them
-Identity card or copy
-2 copies of photo
Талх чихэр ХК
1.Захиралын туслах- 1хүн
Тавигдах шаардлага:
-Гадаад харилцааны чиглэлээр гадаад дотоодын их,дээд сургууль төгссөн,баклавар болон түүнээс дээш зэрэгтэй байх
-Англи,Орос ярианы болон бичгийн хэлийг мэргэжлийн өндөр түвшинд эзэмшсэн байх
-Гадаад хэл дээр бичиг баримт боловсруулах чадвартай байх
-Харилцааны соёл мэргэжлийн ёс зүйтэй байх
-Компьютерийн хэрэглээний программуудыг бүрэн эзэмшсэн байх
- Ажлын дадлага туршлагатай мэргэжлээрээ 3-аас доошгүй жил ажилласан байх
- Идэвх санаачлагатай хувийн зохион байгуулалт сайтай байх
2.Маркетингийн менежер-2 хүн
Тавигдах шаардлага:
-Бизнесийн удирдлага болон менежментийн чиглэлээр гадаад дотоодын их дээд сургууль төгссөн баклавар болон түүнээс дээш зэрэгтэй байх
- Англи,Орос хэлний дундаас дээш түвшний мэдлэгтэй байх
- Ажлын дадлага туршлагатай мэргэжлээрээ 3-аас доошгүй жил ажилласан байх
-Компьютерийн хэрэглээний программуудыг бүрэн эзэмшсэн байх
-Баримт бичиг төлөвлөх боловсруулах судалгаа шинжилгээ хийж дүгнэлт гаргах чадвартай
-Илтгэх ур чадвар сайтай харилцааны өндөр соёлтой
-Ажлын ачаалал дааж бие даан болон багаар хамтран ажиллах чадвартай
- Идэвх санаачлагатай хувийн зохион байгуулалт сайтай байх
Бүрдүүлэх материал:
-Ажилд орохыг хүсэгчийн анкет/байгуулга дээр ирж бөглөх/
-Диплом мэргэжлийн үнэмлэх сертификат түүний хуулбар
-Иргэний үнэмлэх түүний хуулбар
-2 хувь цээж зураг
-Оршин суугаа газрын тодорхойлолт
-Цагдаагийн газрын тодорхойлолт
Хаяг:Улаанбаатар хот СХД 18-р хороо’’Талх Чихэр’’ХК-ийн байр
Холбоо барих утас:11-631526,93220222
Vacancy announcement
1.Assistant to CEO
Requirements:
-Must have Bachelor degree in International Business Communication or more of foriegn or local university
-High level of speaking and writing skill of English and Russian
-Ability of work with documents in foreign language
-Social skill, professional ethic
-Knowledge of computer applications
-3 or more years experience of working
-Be creative, active
2.Manager of Marketing
Requirements:
-Must have Bachelor degree in Business Administration or Management, or more of foriegn or local university
-Intermediate or more English and Russian language skill
-3 or more years experience of working
-Knowledge of computer applications
-Ability of work with documents, research with them
-Social skill, Lecture skill
-Be creative, active
Required items:
-Application /take it from company/
-Diploma, Certificate or copy of them
-Identity card or copy
-2 copies of photo
bayarmaa82@gmail.com
mm mm
Mongolia
Government of Mongolia
VACANCY ANNOUNCEMENT
"Strengthening the Disaster Mitigation and Management System in Mongolia" is a project co-implemented by UNDP and the National Emergency Management Agency (NEMA). It requires services of a short-term National Disaster Education Consultant and a short-term National Secondary Education Consultant who will work full time for 5 months and report to the National Project Manager.
I. Purpose of Assignment
Under the assignment, the Consultants will update the draft Standards for Primary, Incomplete Secondary and Complete Secondary Education Programs on Disaster Protection. Based on the updated standards, they will develop a disaster protection education program, a students' book and a teacher's manual for each of the primary, incomplete secondary, and complete secondary levels of education.
The detailed Terms of Reference of the assignment and more information can be obtained from the project office. Please contact us at tel no. 31-55-95 and 99116802, or email to b.bulqantamir@monaoliadisaster.org .
II. Required qualifications
• The Disaster Education Consultant should meet the following requirements:
o Holds advanced academic degree in disaster management or natural sciences (Master's degree or higher);
o Has a minimum of 5 years of work experience in the disaster response, first-aid delivery, or disaster
education and research fields; o Has at least 1 published book in the area of disaster management, public awareness, or education; o Preferably able to read and understand in English language.
• The Education Expert should meet the following requirements:
o Holds advanced academic degree in secondary education or natural sciences (Master's degree or higher);
o Has a minimum of 5 years of pedagogical experience at a secondary educational institution; o Has experience of developing a secondary educational course program;
o Has at least 1 published book in the area of secondary education, curriculum and educational program
development, public awareness, or disaster management; o Possesses working knowledge of English language;
o Preferably has work experience at the Ministry of Education or its local branches;
• Both Experts need to have excellent communication and team working skills and be available full-time for the assignment;
• Experience of working for or with international organizations in disaster management of educational fields will be an asset for both Experts;
III. Application
If you possess the above qualifications, please submit the following documents in a sealed envelope indicating the post you are applying for at the address below by 16.00 o'clock on 22 March 2010, Monday. Required materials:
• Application letter;
• CV/Resume;
• Reference letter from the last or current employer;
• Copies of higher educational or professional diplomas and certificates.
Address: UNDP Mongolia, UN House (next to the German Embassy), United Nations Street - 12, Sukhbaatar district, Ulaanbaatar
Ажилд шалгаруулж авна
НҮБ-ын Хөгжлийн хөтөлбөр болон Онцгой байдлын ерөнхий газраас хамтран хэрэгжүүлж буй ‘’Монгол Улсад Гамшгын менежментийн тогтолцоог боловсронгуй болгох нь ’’төсөл нь Гамшгын тухай боловсролын үндэсний зөвлөх болон Дунд боловсролын үндэсний зөвлөх шалгаруулж ,5 сарын хугацаанд ажилуулна
Ажлын зорилго
Ажлын хүрээнд зөвлөхүүд Гамшгааш хамгаалах бага дунд бүрэн дунд боловсролын стандартын төслийг шинчлэн сайжруулж тус стандартад үндэслэн гамшгааш хамгаалах бага дунд бүрэн дунд боловсролын хөтөлбөр сурах бичиг багшийн гарын авлага боловсруулна
Ажлын дэлгэрэнгүй удирдамжийг 31-55-95 болон 99116802 дугаарын утсанд
eсвэл b.bulgantamir@mongoliadisaster.org цахим хаягт хандаж болно
Тавигдах шаардлага
Гамшгын боловсролын зөвлөх нь дараах шалгууруудыг хангасан байх ёстой:
• Гамшгын менежент,эсвэл байгал шинжлэлийн чиглэлээр магистр болон түүнээс дээш зэрэгтэй;
• Гамшгын хариу арга хэмжээ анхны тусламж,эсвэл гамшгын судалгаа доод тал нь 5 жил ажилсан туршлагатай;
• Гамшгын менежент, гамшгын боловсрол танин мэдэхүйн чиглэлээр доод тал нь 1 бүтээл хэвлүүлсэн
• Багаар ажиллах болон харилцааны өндөр чадвартай,таван сарын хугацаанд төвлөрөн ажиллах боломжтой;
• Олон улсын байгуулгатай гамшгын менежент, гамшгын боловсролын чиглэлээр хамтран ажиллах байсан бол сайхан;
• Англи хэлээр уншиж ойлгох чадвартай бол сайн
Өгөгдөл гаргах
Дээрх шаардлагад нийцэх хүмүүс 2010 оны 3сарын 22-ны Даваа гарагийн 16:00 цагаас өмнө дараах материалуудыг дугтуйнд хийж,дугтуйны дээр ‘’MON/08/305 Project :NATIONAL CONSULTANT’’гэж бичиж доорх хаягаар хүргэж өгнө үү.
• Ажиллах хүсэлт гаргасан өргөдөл;
• Дэлгэрэнгүй анкет CV;
• Одоо ажилл буй,эсвэл ажиллаж байсан газраас авсан ажил байдлын тодорхойлолт ;
• Дээд боловсролын болон мэргэжлийн диплом,гэрчилгээний хуулбарууд;
Хаяг:НҮБ-ын Хөгжлийн хөтөлбөрийн Суурин төлөөлөгчийн газар,НҮБ-ын байр (Гярманы элчингийн хажууд),
Нэгдсэн үндэсний гудамж-12,Сүхбаатар дүүрэг,Улаанбаатар хот
Mongolia
Government of Mongolia
VACANCY ANNOUNCEMENT
"Strengthening the Disaster Mitigation and Management System in Mongolia" is a project co-implemented by UNDP and the National Emergency Management Agency (NEMA). It requires services of a short-term National Disaster Education Consultant and a short-term National Secondary Education Consultant who will work full time for 5 months and report to the National Project Manager.
I. Purpose of Assignment
Under the assignment, the Consultants will update the draft Standards for Primary, Incomplete Secondary and Complete Secondary Education Programs on Disaster Protection. Based on the updated standards, they will develop a disaster protection education program, a students' book and a teacher's manual for each of the primary, incomplete secondary, and complete secondary levels of education.
The detailed Terms of Reference of the assignment and more information can be obtained from the project office. Please contact us at tel no. 31-55-95 and 99116802, or email to b.bulqantamir@monaoliadisaster.org .
II. Required qualifications
• The Disaster Education Consultant should meet the following requirements:
o Holds advanced academic degree in disaster management or natural sciences (Master's degree or higher);
o Has a minimum of 5 years of work experience in the disaster response, first-aid delivery, or disaster
education and research fields; o Has at least 1 published book in the area of disaster management, public awareness, or education; o Preferably able to read and understand in English language.
• The Education Expert should meet the following requirements:
o Holds advanced academic degree in secondary education or natural sciences (Master's degree or higher);
o Has a minimum of 5 years of pedagogical experience at a secondary educational institution; o Has experience of developing a secondary educational course program;
o Has at least 1 published book in the area of secondary education, curriculum and educational program
development, public awareness, or disaster management; o Possesses working knowledge of English language;
o Preferably has work experience at the Ministry of Education or its local branches;
• Both Experts need to have excellent communication and team working skills and be available full-time for the assignment;
• Experience of working for or with international organizations in disaster management of educational fields will be an asset for both Experts;
III. Application
If you possess the above qualifications, please submit the following documents in a sealed envelope indicating the post you are applying for at the address below by 16.00 o'clock on 22 March 2010, Monday. Required materials:
• Application letter;
• CV/Resume;
• Reference letter from the last or current employer;
• Copies of higher educational or professional diplomas and certificates.
Address: UNDP Mongolia, UN House (next to the German Embassy), United Nations Street - 12, Sukhbaatar district, Ulaanbaatar
Ажилд шалгаруулж авна
НҮБ-ын Хөгжлийн хөтөлбөр болон Онцгой байдлын ерөнхий газраас хамтран хэрэгжүүлж буй ‘’Монгол Улсад Гамшгын менежментийн тогтолцоог боловсронгуй болгох нь ’’төсөл нь Гамшгын тухай боловсролын үндэсний зөвлөх болон Дунд боловсролын үндэсний зөвлөх шалгаруулж ,5 сарын хугацаанд ажилуулна
Ажлын зорилго
Ажлын хүрээнд зөвлөхүүд Гамшгааш хамгаалах бага дунд бүрэн дунд боловсролын стандартын төслийг шинчлэн сайжруулж тус стандартад үндэслэн гамшгааш хамгаалах бага дунд бүрэн дунд боловсролын хөтөлбөр сурах бичиг багшийн гарын авлага боловсруулна
Ажлын дэлгэрэнгүй удирдамжийг 31-55-95 болон 99116802 дугаарын утсанд
eсвэл b.bulgantamir@mongoliadisaster.org цахим хаягт хандаж болно
Тавигдах шаардлага
Гамшгын боловсролын зөвлөх нь дараах шалгууруудыг хангасан байх ёстой:
• Гамшгын менежент,эсвэл байгал шинжлэлийн чиглэлээр магистр болон түүнээс дээш зэрэгтэй;
• Гамшгын хариу арга хэмжээ анхны тусламж,эсвэл гамшгын судалгаа доод тал нь 5 жил ажилсан туршлагатай;
• Гамшгын менежент, гамшгын боловсрол танин мэдэхүйн чиглэлээр доод тал нь 1 бүтээл хэвлүүлсэн
• Багаар ажиллах болон харилцааны өндөр чадвартай,таван сарын хугацаанд төвлөрөн ажиллах боломжтой;
• Олон улсын байгуулгатай гамшгын менежент, гамшгын боловсролын чиглэлээр хамтран ажиллах байсан бол сайхан;
• Англи хэлээр уншиж ойлгох чадвартай бол сайн
Өгөгдөл гаргах
Дээрх шаардлагад нийцэх хүмүүс 2010 оны 3сарын 22-ны Даваа гарагийн 16:00 цагаас өмнө дараах материалуудыг дугтуйнд хийж,дугтуйны дээр ‘’MON/08/305 Project :NATIONAL CONSULTANT’’гэж бичиж доорх хаягаар хүргэж өгнө үү.
• Ажиллах хүсэлт гаргасан өргөдөл;
• Дэлгэрэнгүй анкет CV;
• Одоо ажилл буй,эсвэл ажиллаж байсан газраас авсан ажил байдлын тодорхойлолт ;
• Дээд боловсролын болон мэргэжлийн диплом,гэрчилгээний хуулбарууд;
Хаяг:НҮБ-ын Хөгжлийн хөтөлбөрийн Суурин төлөөлөгчийн газар,НҮБ-ын байр (Гярманы элчингийн хажууд),
Нэгдсэн үндэсний гудамж-12,Сүхбаатар дүүрэг,Улаанбаатар хот
mm mm
Mongolia
Government of Mongolia
VACANCY ANNOUNCEMENT
"Strengthening the Disaster Mitigation and Management System in Mongolia" is a project co-implemented by UNDP and the National Emergency Management Agency (NEMA). It requires services of a short-term National Disaster Education Consultant and a short-term National Secondary Education Consultant who will work full time for 5 months and report to the National Project Manager.
I. Purpose of Assignment
Under the assignment, the Consultants will update the draft Standards for Primary, Incomplete Secondary and Complete Secondary Education Programs on Disaster Protection. Based on the updated standards, they will develop a disaster protection education program, a students' book and a teacher's manual for each of the primary, incomplete secondary, and complete secondary levels of education.
The detailed Terms of Reference of the assignment and more information can be obtained from the project office. Please contact us at tel no. 31-55-95 and 99116802, or email to b.bulqantamir@monaoliadisaster.org .
II. Required qualifications
• The Disaster Education Consultant should meet the following requirements:
o Holds advanced academic degree in disaster management or natural sciences (Master's degree or higher);
o Has a minimum of 5 years of work experience in the disaster response, first-aid delivery, or disaster
education and research fields; o Has at least 1 published book in the area of disaster management, public awareness, or education; o Preferably able to read and understand in English language.
• The Education Expert should meet the following requirements:
o Holds advanced academic degree in secondary education or natural sciences (Master's degree or higher);
o Has a minimum of 5 years of pedagogical experience at a secondary educational institution; o Has experience of developing a secondary educational course program;
o Has at least 1 published book in the area of secondary education, curriculum and educational program
development, public awareness, or disaster management; o Possesses working knowledge of English language;
o Preferably has work experience at the Ministry of Education or its local branches;
• Both Experts need to have excellent communication and team working skills and be available full-time for the assignment;
• Experience of working for or with international organizations in disaster management of educational fields will be an asset for both Experts;
III. Application
If you possess the above qualifications, please submit the following documents in a sealed envelope indicating the post you are applying for at the address below by 16.00 o'clock on 22 March 2010, Monday. Required materials:
• Application letter;
• CV/Resume;
• Reference letter from the last or current employer;
• Copies of higher educational or professional diplomas and certificates.
Address: UNDP Mongolia, UN House (next to the German Embassy), United Nations Street - 12, Sukhbaatar district, Ulaanbaatar
Ажилд шалгаруулж авна
НҮБ-ын Хөгжлийн хөтөлбөр болон Онцгой байдлын ерөнхий газраас хамтран хэрэгжүүлж буй ‘’Монгол Улсад Гамшгын менежментийн тогтолцоог боловсронгуй болгох нь ’’төсөл нь Гамшгын тухай боловсролын үндэсний зөвлөх болон Дунд боловсролын үндэсний зөвлөх шалгаруулж ,5 сарын хугацаанд ажилуулна
Ажлын зорилго
Ажлын хүрээнд зөвлөхүүд Гамшгааш хамгаалах бага дунд бүрэн дунд боловсролын стандартын төслийг шинчлэн сайжруулж тус стандартад үндэслэн гамшгааш хамгаалах бага дунд бүрэн дунд боловсролын хөтөлбөр сурах бичиг багшийн гарын авлага боловсруулна
Ажлын дэлгэрэнгүй удирдамжийг 31-55-95 болон 99116802 дугаарын утсанд
eсвэл b.bulgantamir@mongoliadisaster.org цахим хаягт хандаж болно
Тавигдах шаардлага
Гамшгын боловсролын зөвлөх нь дараах шалгууруудыг хангасан байх ёстой:
• Гамшгын менежент,эсвэл байгал шинжлэлийн чиглэлээр магистр болон түүнээс дээш зэрэгтэй;
• Гамшгын хариу арга хэмжээ анхны тусламж,эсвэл гамшгын судалгаа доод тал нь 5 жил ажилсан туршлагатай;
• Гамшгын менежент, гамшгын боловсрол танин мэдэхүйн чиглэлээр доод тал нь 1 бүтээл хэвлүүлсэн
• Багаар ажиллах болон харилцааны өндөр чадвартай,таван сарын хугацаанд төвлөрөн ажиллах боломжтой;
• Олон улсын байгуулгатай гамшгын менежент, гамшгын боловсролын чиглэлээр хамтран ажиллах байсан бол сайхан;
• Англи хэлээр уншиж ойлгох чадвартай бол сайн
Өгөгдөл гаргах
Дээрх шаардлагад нийцэх хүмүүс 2010 оны 3сарын 22-ны Даваа гарагийн 16:00 цагаас өмнө дараах материалуудыг дугтуйнд хийж,дугтуйны дээр ‘’MON/08/305 Project :NATIONAL CONSULTANT’’гэж бичиж доорх хаягаар хүргэж өгнө үү.
• Ажиллах хүсэлт гаргасан өргөдөл;
• Дэлгэрэнгүй анкет CV;
• Одоо ажилл буй,эсвэл ажиллаж байсан газраас авсан ажил байдлын тодорхойлолт ;
• Дээд боловсролын болон мэргэжлийн диплом,гэрчилгээний хуулбарууд;
Хаяг:НҮБ-ын Хөгжлийн хөтөлбөрийн Суурин төлөөлөгчийн газар,НҮБ-ын байр (Гярманы элчингийн хажууд),
Нэгдсэн үндэсний гудамж-12,Сүхбаатар дүүрэг,Улаанбаатар хот
Mongolia
Government of Mongolia
VACANCY ANNOUNCEMENT
"Strengthening the Disaster Mitigation and Management System in Mongolia" is a project co-implemented by UNDP and the National Emergency Management Agency (NEMA). It requires services of a short-term National Disaster Education Consultant and a short-term National Secondary Education Consultant who will work full time for 5 months and report to the National Project Manager.
I. Purpose of Assignment
Under the assignment, the Consultants will update the draft Standards for Primary, Incomplete Secondary and Complete Secondary Education Programs on Disaster Protection. Based on the updated standards, they will develop a disaster protection education program, a students' book and a teacher's manual for each of the primary, incomplete secondary, and complete secondary levels of education.
The detailed Terms of Reference of the assignment and more information can be obtained from the project office. Please contact us at tel no. 31-55-95 and 99116802, or email to b.bulqantamir@monaoliadisaster.org .
II. Required qualifications
• The Disaster Education Consultant should meet the following requirements:
o Holds advanced academic degree in disaster management or natural sciences (Master's degree or higher);
o Has a minimum of 5 years of work experience in the disaster response, first-aid delivery, or disaster
education and research fields; o Has at least 1 published book in the area of disaster management, public awareness, or education; o Preferably able to read and understand in English language.
• The Education Expert should meet the following requirements:
o Holds advanced academic degree in secondary education or natural sciences (Master's degree or higher);
o Has a minimum of 5 years of pedagogical experience at a secondary educational institution; o Has experience of developing a secondary educational course program;
o Has at least 1 published book in the area of secondary education, curriculum and educational program
development, public awareness, or disaster management; o Possesses working knowledge of English language;
o Preferably has work experience at the Ministry of Education or its local branches;
• Both Experts need to have excellent communication and team working skills and be available full-time for the assignment;
• Experience of working for or with international organizations in disaster management of educational fields will be an asset for both Experts;
III. Application
If you possess the above qualifications, please submit the following documents in a sealed envelope indicating the post you are applying for at the address below by 16.00 o'clock on 22 March 2010, Monday. Required materials:
• Application letter;
• CV/Resume;
• Reference letter from the last or current employer;
• Copies of higher educational or professional diplomas and certificates.
Address: UNDP Mongolia, UN House (next to the German Embassy), United Nations Street - 12, Sukhbaatar district, Ulaanbaatar
Ажилд шалгаруулж авна
НҮБ-ын Хөгжлийн хөтөлбөр болон Онцгой байдлын ерөнхий газраас хамтран хэрэгжүүлж буй ‘’Монгол Улсад Гамшгын менежментийн тогтолцоог боловсронгуй болгох нь ’’төсөл нь Гамшгын тухай боловсролын үндэсний зөвлөх болон Дунд боловсролын үндэсний зөвлөх шалгаруулж ,5 сарын хугацаанд ажилуулна
Ажлын зорилго
Ажлын хүрээнд зөвлөхүүд Гамшгааш хамгаалах бага дунд бүрэн дунд боловсролын стандартын төслийг шинчлэн сайжруулж тус стандартад үндэслэн гамшгааш хамгаалах бага дунд бүрэн дунд боловсролын хөтөлбөр сурах бичиг багшийн гарын авлага боловсруулна
Ажлын дэлгэрэнгүй удирдамжийг 31-55-95 болон 99116802 дугаарын утсанд
eсвэл b.bulgantamir@mongoliadisaster.org цахим хаягт хандаж болно
Тавигдах шаардлага
Гамшгын боловсролын зөвлөх нь дараах шалгууруудыг хангасан байх ёстой:
• Гамшгын менежент,эсвэл байгал шинжлэлийн чиглэлээр магистр болон түүнээс дээш зэрэгтэй;
• Гамшгын хариу арга хэмжээ анхны тусламж,эсвэл гамшгын судалгаа доод тал нь 5 жил ажилсан туршлагатай;
• Гамшгын менежент, гамшгын боловсрол танин мэдэхүйн чиглэлээр доод тал нь 1 бүтээл хэвлүүлсэн
• Багаар ажиллах болон харилцааны өндөр чадвартай,таван сарын хугацаанд төвлөрөн ажиллах боломжтой;
• Олон улсын байгуулгатай гамшгын менежент, гамшгын боловсролын чиглэлээр хамтран ажиллах байсан бол сайхан;
• Англи хэлээр уншиж ойлгох чадвартай бол сайн
Өгөгдөл гаргах
Дээрх шаардлагад нийцэх хүмүүс 2010 оны 3сарын 22-ны Даваа гарагийн 16:00 цагаас өмнө дараах материалуудыг дугтуйнд хийж,дугтуйны дээр ‘’MON/08/305 Project :NATIONAL CONSULTANT’’гэж бичиж доорх хаягаар хүргэж өгнө үү.
• Ажиллах хүсэлт гаргасан өргөдөл;
• Дэлгэрэнгүй анкет CV;
• Одоо ажилл буй,эсвэл ажиллаж байсан газраас авсан ажил байдлын тодорхойлолт ;
• Дээд боловсролын болон мэргэжлийн диплом,гэрчилгээний хуулбарууд;
Хаяг:НҮБ-ын Хөгжлийн хөтөлбөрийн Суурин төлөөлөгчийн газар,НҮБ-ын байр (Гярманы элчингийн хажууд),
Нэгдсэн үндэсний гудамж-12,Сүхбаатар дүүрэг,Улаанбаатар хот
Ажилд шалгаруулж авна
Талх чихэр ХК
1.Захиралын туслах- 1хүн
Тавигдах шаардлага:
-Гадаад харилцааны чиглэлээр гадаад дотоодын их,дээд сургууль төгссөн,баклавар болон түүнээс дээш зэрэгтэй байх
-Англи,Орос ярианы болон бичгийн хэлийг мэргэжлийн өндөр түвшинд эзэмшсэн байх
-Гадаад хэл дээр бичиг баримт боловсруулах чадвартай байх
-Харилцааны соёл мэргэжлийн ёс зүйтэй байх
-Компьютерийн хэрэглээний программуудыг бүрэн эзэмшсэн байх
- Ажлын дадлага туршлагатай мэргэжлээрээ 3-аас доошгүй жил ажилласан байх
- Идэвх санаачлагатай хувийн зохион байгуулалт сайтай байх
2.Маркетингийн менежер-2 хүн
Тавигдах шаардлага:
-Бизнесийн удирдлага болон менежментийн чиглэлээр гадаад дотоодын их дээд сургууль төгссөн баклавар болон түүнээс дээш зэрэгтэй байх
- Англи,Орос хэлний дундаас дээш түвшний мэдлэгтэй байх
- Ажлын дадлага туршлагатай мэргэжлээрээ 3-аас доошгүй жил ажилласан байх
-Компьютерийн хэрэглээний программуудыг бүрэн эзэмшсэн байх
-Баримт бичиг төлөвлөх боловсруулах судалгаа шинжилгээ хийж дүгнэлт гаргах чадвартай
-Илтгэх ур чадвар сайтай харилцааны өндөр соёлтой
-Ажлын ачаалал дааж бие даан болон багаар хамтран ажиллах чадвартай
- Идэвх санаачлагатай хувийн зохион байгуулалт сайтай байх
Бүрдүүлэх материал:
-Ажилд орохыг хүсэгчийн анкет/байгуулга дээр ирж бөглөх/
-Диплом мэргэжлийн үнэмлэх сертификат түүний хуулбар
-Иргэний үнэмлэх түүний хуулбар
-2 хувь цээж зураг
-Оршин суугаа газрын тодорхойлолт
-Цагдаагийн газрын тодорхойлолт
Хаяг:Улаанбаатар хот СХД 18-р хороо’’Талх Чихэр’’ХК-ийн байр
Холбоо барих утас:11-631526,93220222
Vacancy announcement
1.Assistant to CEO
Requirements:
-Must have Bachelor degree in International Business Communication or more of foriegn or local university
-High level of speaking and writing skill of English and Russian
-Ability of work with documents in foreign language
-Social skill, professional ethic
-Knowledge of computer applications
-3 or more years experience of working
-Be creative, active
2.Manager of Marketing
Requirements:
-Must have Bachelor degree in Business Administration or Management, or more of foriegn or local university
-Intermediate or more English and Russian language skill
-3 or more years experience of working
-Knowledge of computer applications
-Ability of work with documents, research with them
-Social skill, Lecture skill
-Be creative, active
Required items:
-Application /take it from company/
-Diploma, Certificate or copy of them
-Identity card or copy
-2 copies of photo
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