how to reserve bandwidth with MPLS?

[jamesma01]

Tunnel MPLS traffic-enginerring bandwitdh XXX,

does this command guarantee any bandwidth along LSP?

[Mahesh Gohil]

Yes ! under tunnel configuration this command reserve bandwidth specified. If BW not available LSP will not setup.

Regards

[jamesma01]

Hi, Mahesh,

Please refer to link below. It says this command would only check control plan if the resource is available, but it does nothing on data plan. As result, even if you have this tunnel set up, there is no bandwidth guarantee to data sent onto the tunnel. That's what I want to clarify.

https://supportforums.cisco.com/discussion/9784116/mpls-te-tunnel-bandwidth-and-ip-rsvp-bandwidth

[Akash Agrawal]

Hi,

Yes this is correct. Bandwidth configuration under TE tunnel plays role only during tunnel setup and reserves bandwidth on transit links. Like if ten 100mbps tunnels are passing through a Gig link, 11th tunnel will not be able to get established. But for data forwarding a 1kbps tunnel can also carry 1gig traffic. During traffic forwarding, router refers just CEF/LIB and it has just labels but no info about bandwidth reserved by that label (LSP).

Regards,

Akash

[Mahesh Gohil]

Hello Akash,

Nice to know that this feature is at control plane only.

We never used bandwidth reservation :)

Thanks again.

Regards

Mahesh