Subject: RE: Question on tunnel Interface (w.r.t TE MIB)

From: "Dominic-Savio, Patrick" <[email-masked]>
Date: Tue, 30 Oct 2001 10:07:24 -0500

Please scroll to the end...

-----Original Message-----
From: Thomas Nadeau [mailto:[email-masked]]
Sent: Monday, October 29, 2001 7:11 PM
To: Dominic-Savio, Patrick
Cc: [email-masked]'
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.

---

From: "Adrian Farrel" <[email-masked]>
Date: Tue, 30 Oct 2001 10:17:08 -0500

Guys,

Before banging on the TE-MIB much more, apply yourselves to Tom's question...

How is this signaled?

The TE MIB can only handle two things...

- local configuration (e.g. head end ifIndex)
- protocol elements (i.e. things that will be signaled)

Note that the Unnumbered Interface signaling drafts add the concept of signaling the Unnumbered Interface Id by which the tunnel is known if it is represented as an unnumbered interface.  This is being added to the GMPLS version of the TE MIB (due out any time soon).

I'm sure that just as soon as it is agreed how to signal the tail end ifIndex for tunnels that appear as numbered interfaces, Tom will be happy to add this to the TE MIB.

Adrian
--
Adrian Farrel
Movaz Networks Inc.
Tel: 703-847-1867
[email-masked]

    -----Original Message-----
    From: Thomas Nadeau [mailto:[email-masked]]
    Sent: Monday, October 29, 2001 7:11 PM
    To: Dominic-Savio, Patrick
    Cc: [email-masked]'
    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. 

      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.   

       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. 

    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

---

From: Thomas Nadeau <[email-masked]>
Date: Tue, 30 Oct 2001 10:45:54 -0500

>Note that the Unnumbered Interface signaling drafts add the concept of 
>signaling the Unnumbered Interface Id by which the tunnel is known if it 
>is represented as an unnumbered interface.  This is being added to the 
>GMPLS version of the TE MIB (due out any time soon).
>
>I'm sure that just as soon as it is agreed how to signal the tail end 
>ifIndex for tunnels that appear as numbered interfaces, Tom will be happy 
>to add this to the TE MIB.\

         The signaling issue aside, I believe that the MPLS TE MIB can 
handle this
configuration today, albeit manually or via the agent picking an ifIndex at the
tail. Now if you want the ifIndex to be consistent with the one at the head,
or you want the head to know what the tail ifIndex is, then Adrian is right, we
will need the signaling to be worked out so that the tail can be provided with
this information via the signaling.

         --Tom

>Adrian
>--
>Adrian Farrel
>Movaz Networks Inc.
>Tel: 703-847-1867
><mailto:[email-masked]>[email-masked]
>>From: <mailto:[email-masked]>Dominic-Savio, Patrick
>>To: <mailto:[email-masked]>'Thomas Nadeau'
>>Cc: <mailto:[email-masked]'>[email-masked]'
>>>From: Thomas Nadeau [<mailto:[email-masked]>mailto:[email-masked]]
>>>Cc: <mailto:[email-masked]'>[email-masked]'
>>>>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.
>>>
>>>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).
>>>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
>>>
>>>
>>>
>>>