MPLS TE bandwidth questions

Latest reply: Sep 30, 2018 09:44:44 3517 6 0 0

Dear all,

 

I have been studing MPLS TE technology and I have some doubts about it. I hope you can help me. My doubts are the following:

 

1 - Who carry the bandwidth information, the IGP or RSVP-TE?

 

2 - What's the difference or meaning between the following terms (an example could be useful):

    a) Max-link-bandwidth

    b) Max-reservable-bandwidth

    c) Max-available-bandwidth

    d) "mpls te bandwidth bc0" command

 

3 - Why the actual interface bandwidth is at most 80% of the physical bandwidth?

 

Thank you in advance,

Julián 

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Created Mar 10, 2014 07:11:08 Helpful(0) Helpful(0)

RSVP-TE carry the bandwidth information

Why the actual interface bandwidth is at most 80% of the physical bandwidth?  —— If over 60%-70%, we advice bandwidth expansion.

 

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Created Mar 10, 2014 09:40:08 Helpful(0) Helpful(0)

2 - What's the difference or meaning between the following terms (an example could be useful):

    a) Max-link-bandwidth------->I didn't find this command, would you please clarify where did you find it?

    b) Max-reservable-bandwidth------>Means the max bandwidth for MPLS TE tunnel

    c) Max-available-bandwidth------>I didn't find this command, would you please clarify where did you find it?

    d) "mpls te bandwidth bc0" command----->Means the max total bandwidth for CT(class type) 0.

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Created Mar 11, 2014 01:13:54 Helpful(0) Helpful(0)

Hi everyone,

 

About question 1)

 

1 - Who carry the bandwidth information, the IGP or RSVP-TE?

 

From HedEx:

 

Information advertisement: Extends an IGP to advertise TE information, in addition to routing information. TE information includes the maximum link bandwidth, maximum reservable bandwidth, reserved bandwidth, and link colors.

Every node collects TE information about all nodes in a local area and generates a traffic engineering database (TEDB).

 

RSVP-TE Overview
The Resource Reservation Protocol (RSVP) is designed for the integrated service model and used on each node along a path for resource reservation. The bandwidth reservation capability makes it a suitable signaling protocol for establishing an MPLS TE tunnel.

RSVP-TE is an extension of RSVP to meet MPLS TE requirements. RSVP-TE extends RSVP in the following aspects:
RSVP-TE appends Label Request objects to Path messages to request labels. Resv messages carry Label objects that are used to allocate labels.

The extended RSVP messages can carry information about path constraint parameters, in addition to label binding information.

RSVP-TE provides the resource reservation function by supporting MPLS TE bandwidth constraints through the extended objects.

 

So it seems the IGP carries the bandwidth information and RSVP-TE reserves the resources along a path. RSVP-TE carries information about path constraint, but from HedEx --> Path constraint: includes the explicit path, priority and preemption, route pinning, affinity attribute, and hop limit. It seems bandwidth isn't a path constraint so RSVP-TE doesn't carry bandwidth information.

Am I right?

 

Julián

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Created Mar 11, 2014 01:31:34 Helpful(0) Helpful(0)

Hi all,

 

a) Max-link-bandwidth------->I didn't find this command, would you please clarify where did you find it?

 

It is not a command, it is a term. Anyways, there is this command:

 

mpls te bandwidth max-reservable-bandwidth bw-value (kbit/s)

 

c) Max-available-bandwidth------>I didn't find this command, would you please clarify where did you find it?

 

It is not a command, it is a term. From the HCDP-BITN: The MPLS TE tunnel supports eight tunnel priority levels, namely, 0-7. The tunnels with different priority levels support preemption. The maximum available bandwidth for each priority can be specifid for each interface.

 

For instance, for our customer, I can find this two commands in every physical interface along a TE tunnel:

 

mpls te bandwidth max-reservable-bandwidth 750000
mpls te bandwidth bc0 750000

 

What's the meaning?

 

Best regards,

Julián

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Created Mar 16, 2014 15:26:34 Helpful(0) Helpful(0)

Reply 3 #

Hi dears,

 

¿Any update?

 

Regards,

Julián

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Created Sep 30, 2018 09:44:44 Helpful(0) Helpful(0)

Hope your questions have been answered
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