Concerning MPLS paths

Pshem Kowalczyk pshem.k at
Tue Apr 28 16:06:57 CDT 2009


2009/4/28 Saqib Ilyas <msaqib at>:
> Hello everyone
> In the context of a single service provider network running MPLS, if a
> number of bandwidth constrained LSPs are passing through a particular node
> and the sum of the bandwidth constraints for the LSPs is X Mb/s, then is X
> the upper bound on the traffic through that node, or is it sometimes
> exceeded as well?

>From my experience with RSVP-TE and LSP tunnels the bandwidth you pin
down for a tunnel is only reserved, not guaranteed. There is nothing
stopping you from creating a 10Mb/s LSP and sending 20Mb/s down
through it. By default only the ingress LSR can do the
policing/shaping. If you don't to that at the head than the rest of
the network will just happily pass the traffic defaulting to its
normal queue handling.
So to answer to your question is - yes you might see more traffic then
you've reserved.

kind regards

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