The MPLS WG Archive

["Dominic-Savio, Patrick" <Patrick.Dominic-Savio@marconi.com>]

Please scroll to the end...

-----Original Message-----
From: Thomas Nadeau [mailto:tnadeau@cisco.com]
Sent: Monday, October 29, 2001 7:11 PM
To: Dominic-Savio, Patrick
Cc: 'mpls@uu.net'
Subject: RE: Question on tunnel Interface (w.r.t TE MIB)

        Most if not all MPLS implementations that I know of only require the operator
to configure the tunnel at the head end.
 
But, if you want to treat a tunnel as a real interface (and assign IP addresses etc. to it at both ends)

        I would categorize the use of a single interface as a "real" interface
configuration as well.

you will have to have interface configuration at both the head and tail ends.

        That is possible using the existing MIB. I think that we have
violent agreement on this point.

If you don't have a tail end interface configuration the only reason to use tunnel interfaces is probably to make the tunnel *look* like an interface on the head end router. This however means that you are treating it as an interface on one side and treating it as a simple terminating tunnel on the other side. This seems anomalous.   

        I guess that you are entitled to your opinion. My customers
don't think that this approach is so anomalous.

 If your implementation wishes to create an
interface for the tail end of the tunnel, it can do this based on the acceptance of
an RSVP-TE session at the tail point, or via manual configuration. However, making
this ifIndex consistent with the one at the head automatically is something that I think you
will have to do manually.
 
I think you misunderstood, the actual value of the ifIndex is of no consequence,
you just have to have a corresponding interface at the other end.

        Okay, so what is the problem then? 8) 

 

The problem is that the TE MIB does not provide *complete* configuration support for setting up of a "corresponding" tail-end tunnel interface. On the head-end it provides all of the required configuration parameters (isIf, name) and on the tail-end it provides some (isIf, name) but not all (you would at least need the head-end tunnel index to be specified at the tail-end).

Let me try the question again in case my earlier questions were not clear.

If I create a tunnel  interface on a head-end router and would like to create a corresponding tail-end tunnel interface on the tail-end router, how do I do this using the TE MIB. I would like to see a complete solution using just the TE MIB (because it attempts to solve the problem on the head-end), if this is not possible then what other MIB tables should I use and how?. I can easily come up with some proprietary scheme to do this but I would like to see some "standard" usage guidelines. Again, given that the TE MIB seems to be taking on the responsibility of creating tunnel interfaces I would like a "standard" way of doing it on the tail-end to be documented in the mpls-te-mib specification.

 

Thanks

 

 

        --Tom

------------------------------------------------------------------------

Mathematics is the supreme nostalgia of our time.