Configuraton of the maximum available bandwidth

Answered Question
May 21st, 2007
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The new extension add to ospf (ospf-te) and rsvp (rsvp-te) allow to specifie the amount of bandwidth available for eight priority levels.

The initial values are all set to the Maximum Reservable Bandwidth. These values are flooded by all routers to provide link estate.

I would like to know if theses values could be configured in order to put non- default values.


For example, an interface has a 100Mbps maximum reservable bandwidth.

I just want to know it is possible to put maximum reservable bandwidth to priority level 0 at 60Mbps, to put maximum reservable bandwidth to priority level 1 at 90Mbps, etc?


Thanks for your response.

Correct Answer by swaroop.potdar about 9 years 10 months ago

To achieve as close as possible to what you need here you will have to configure, Diff-Serv Aware TE tunnels and then use Class based Tunnel Selection to forward appropriate EXP/Class traffic onto the respective Tunnels.


But, currently to my knowledge you can have only 2 levels within an LSP. One global and one sub-pool, this sub pool you may want to allocate to premium class traffic, and use the global pool for all other class of traffic.


Although as per the IETF standards rather than 1 sub-pool 7 levels(sub-pools) can be supported, its best to check with your local SE what is the road map regarding the same. Although this surely may be in the pipeline.


Configure DS-TE Tunnels.

http://www.cisco.com/en/US/products/ps6922/products_feature_guide09186a00807fb78c.html


Configure Class Based Tunnel Selection.

http://www.cisco.com/en/US/products/sw/iosswrel/ps1829/products_feature_guide09186a00802659b9.html


HTH-Cheers,

Swaroop

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mheusinger Tue, 05/22/2007 - 04:09
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Hello,


The way the reservable bandwidth per priority level works is as follows:

IF no other traffic is reserved, all bandwidth can be reserved by any level. The bandwidth available for levels with higher priority (lower decimal values) will not be changed. Thus a "high priority" tunnel is allowed to "bump" a "lower priority" tunnel off a specific link.


Given this implementation the answer to your question is "no". In fact I do not see the advantages of your suggested implementation compared to the implementation at hand. Which scenario/issue do you try to address?


Regards, Martin

Djule2804 Tue, 05/22/2007 - 07:02
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Thank you for your response, Martin.


I wanted to built a MPLS domain and assign maximum bandwitdth value for a specific stream (high priority traffic stream) on each router in order to provide service guarantiees to the voice traffic.

The bandwidth available for the voice traffic is limited to the percentage of the link required to ensure small queuing delays.

And I think it is possible with DS-TE.

After having studied RFC4124, it seems to be possible to put bandwidth constraint (BC) for a specific class type (CT). I saw extensions had been added to OSPF and RSVP to carry these information. According to what i could read, this extension consern only L-LSP, isn't it?

I would like to know which command allow to put the BC on the router.

The available bandwidth related to a CT would correspond to the available bandwidth of a specific queue. OSPF flooding message periodically to inform on CTs available bandwidth, how the router can do the relation between the available bandwidth of a specific queue and the value corresponding to the available bandwidth of a CT . I don't if I have been clear on my interrogations?


Regards, Julien

Correct Answer
swaroop.potdar Tue, 05/22/2007 - 14:15
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To achieve as close as possible to what you need here you will have to configure, Diff-Serv Aware TE tunnels and then use Class based Tunnel Selection to forward appropriate EXP/Class traffic onto the respective Tunnels.


But, currently to my knowledge you can have only 2 levels within an LSP. One global and one sub-pool, this sub pool you may want to allocate to premium class traffic, and use the global pool for all other class of traffic.


Although as per the IETF standards rather than 1 sub-pool 7 levels(sub-pools) can be supported, its best to check with your local SE what is the road map regarding the same. Although this surely may be in the pipeline.


Configure DS-TE Tunnels.

http://www.cisco.com/en/US/products/ps6922/products_feature_guide09186a00807fb78c.html


Configure Class Based Tunnel Selection.

http://www.cisco.com/en/US/products/sw/iosswrel/ps1829/products_feature_guide09186a00802659b9.html


HTH-Cheers,

Swaroop

Djule2804 Wed, 05/23/2007 - 04:45
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Thank you very much for your response.


You're all right. Here is what I could read in the documents you advise me :


As the IETF work is still in progress, details are still under definition and subject to change, so DS-TE should be considered as a pre-standard implementation of IETF DiffServ-aware MPLS Traffic Engineering. However, it is in line with the requirements described in the first document above. The concept of "Class-Type" defined in that IETF draft corresponds to the concept of bandwidth pool implemented by DS-TE. And because DS-TE supports two bandwidth pools (global pool and sub-pool), DS-TE should be seen as supporting two Class-Types (Class-Type 0 and Class-Type 1).


But I don't understand what you explain me in your last sentence


"Although as per the IETF standards rather than 1 sub-pool 7 levels(sub-pools) can be supported, its best to check with your local SE what is the road map regarding the same. Although this surely may be in the pipeline"


Could you be more precise please?

swaroop.potdar Wed, 05/23/2007 - 06:25
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The work is in progress with Cisco as well to implement total 8 pools (1 global and 7 sub pools).

Regarding when would you see it in the IOS (roadmap), you can consult your account SE from Cisco.


HTH-Cheers,

Swaroop

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