The MPLS WG Archive

[Lou Berger <lberger@labn.net>]

See below.

At 12:01 PM 9/28/00, Markus Jork wrote:
>Adrian,
>
>it seems to me the invention of the Notify message in GMPLS was not
>such a great idea. It's only purpose is to reduce the latency of
>error message delivery back to the LSP ingress. So instead of the
>slow path forwarding of the PathErr message by the router software
>you now get fast path forwarding of the Notify message by the router
>hardware.
>Does this gain justify the circumvention of RSVP's authentication
>mechanism (RFC 2747)? RSVP security is based on message authentication
>between neighbors but the Notify message is not send hop-by-hop
>through neighboring routers that are configured to trust each other.
>You now also point this out in your rewrite of section 5.1.1.
>
>There is also no discussion of backwards compatibility.
>In your modified version of section 5, you write:
>
>    The Notify message does not replace existing error messages, but may
>    initially be sent instead of existing error messages where the intent
>    is that the Notify recipient should take remedial action before the
>    network has recourse to the normal error processing.
>
>Because the Notify message is sent instead of a regular PathErr
>message, a node that receives the Notify but does not support it
>will not get any error indication from RSVP signalling at all!

I think it's worth pointing out that Adrian's version differs from the most 
recent draft, which says "The Notify message does not replace existing 
error messages. "  I think any attempt to replace base RSVP messages with a 
notify would be misguided.  I don't know if this is what Adrian meant to 
imply.  (Although this is one reading of the his text.)

>I suggest to remove the Notify message from the GMPLS draft.

This would be fine with me particularly since a PathErr message doesn't 
modify state.  (I'm sure some of my co-authors will disagree with me on 
dropping it.)

Lou

>If not, the "Security Considerations" section needs to be updated:
>the Notify message *does* introduce new security issues.
>
>Markus