Subject: RSVP-TE label recording question

From: David Charlap <[email-masked]>
Date: Tue, 05 Mar 2002 11:41:51 -0500

When label recording is requested (in the session attributes), which
label do we record in the RRO?

Do we record the phop-label (the one we generate and send upstream)?
Do we record the nhop-label (the one we receive from downstream)?
Do we record both of them?

RFC 3209 isn't clear about this.

My instinct says that we should record the phop-label, since that's the
one we're generating.  IMO, it doesn't make sense to record a label that
was generated by another router.

Could one of the RFC authors possibly confirm this?

Thanks in advance.

-- David

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From: Jean Philippe Vasseur <[email-masked]>
Date: Tue, 05 Mar 2002 17:56:02 +0100

>Do we record the phop-label (the one we generate and send upstream)?

yes.

JP.

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From: Sachin Kalra <[email-masked]>
Date: Tue, 05 Mar 2002 12:07:00 -0500

David:

It makes more sense to record phop-label, i.e. the one that node generates 
and send upstream.

This is because during fast reroute PLR (Point of Local Recovery) checks 
for the phop-label for MN (Merge Node), and then assigns the new labels 
accordingly.

I cannot think of any good reason why would we need to record nhop-label.

Regards,
Sachin Kalra

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From: George Swallow <[email-masked]>
Date: Tue, 05 Mar 2002 12:15:23 -0500

> was generated by another router.

Correct.

...George

==================================================================
George Swallow       Cisco Systems                  (978) 497-8143
                     250 Apollo Drive
                     Chelmsford, Ma 01824

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From: "Arumugamr" <[email-masked]>
Date: Wed, 6 Mar 2002 11:37:52 +0530

I think it should be the phop label.

Since the label recording starts from Egress, the Egress is the one which
adds the label first. Since the Egress
does not have any downstream, it is obvious that it will always add the phop
label.

The phop which is received in the RRO from Egress (Resv message) should have
to add a label. The label to be added
will be the label given to its upstream. it need not add the nhop label
since it had been already added by the Egress.

Hope the authors will make it more clearer.

Reg
Arumugam

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From: "Doug Degan" <[email-masked]>
Date: Wed, 6 Mar 2002 12:37:49 +0200

When route recording is requested which
 addresses do we record in the RRO?
 
 Do we record the node's ip address?
Do we record the incoming link's ip address?
Do we record both of them?

 Thanks in advance.

doug