Subject: Bandwidth question

From: Paul Moore <[email-masked]>
Date: Thu, 01 Mar 2001 18:18:18 +0100

The MPLS MIB has the table, mplsTrafficParamTable which describes
bandwidth allocation for in- and out-segments. The TE MIB also has the
table, mplsTunnelResourceTable, which allows the bandwidth required for
a tunnel to be specified. Both tables indicate that they can be pointed
to multiple times, to indicate that the specified resource should be
shared.

How would this work in practice, in the case where an operator is trying
to set up traffic engineered tunnels? Preseumably, he would specify the
bandwidth required, and allow signalling to ensure that the tunnel is
set up, ensuring that the various constraints such as bandwidth or
explicit route are satisfied. The bandwidth constraint in this case
would appear as an entry in the mplsTunnelResourceTable. 

What then is the purpose of the mplsTrafficParamTable? Is is filled
in/updated for each in-and out-segment when the tunnel is finally
established? In that case, why should an entry in the table be pointed
to multiple times? Or does this table imply that further configuration
is required?

Confused,
Paul

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From: "Thomas D. Nadeau" <[email-masked]>
Date: Thu, 01 Mar 2001 17:36:53 -0500

>to multiple times? Or does this table imply that further configuration

         Paul, you are correct that in practice, I have only seen folks
point at this table on a 1-to-1 basis. In theory, it was originally
thought that when setting up bi-directional tunnels, that it
would be possible to allocate the same resources (sort of like
using a VPI for both tunnels). Speaking for my implementation,
For every tunnel instance I always point it at its own
resource entry because each instance may have different bandwidth
constraints. Making this assumption makes the implementation
much easier.

         Hope that helps lessen your confusion.

         --Tom