RE: Source routed Notify message

["Vishal Sharma" <v.sharma@ieee.org>]

Diego,

I think the problem you're looking at is still a bit ill-defined.
(BTW, you have two nodes labeled H in the fig. below,
which one is A trying to inform?) 

Assuming that the lower rightmost node is H, here are
a few questions...

Are you assuming, for example, that the DCN used for the SDH/SONET
network uses an associated control plane (with the same
topology as the data plane)?
If not, then the IP message from A should be able to find its way
easily enough to H, via the DCN.

Further, if "lower layer" data plane mechanisms are at
work, then the same mechanisms would have informed H as well,
so why does A need to do anything special to inform H?

In any case, since the Notify message is an IP packet, it could 
always be IP source-routed (if A so desired), with some attendant 
limitations on size of course.

-Vishal

> -----Original Message-----
> From: owner-ccamp@ops.ietf.org [mailto:owner-ccamp@ops.ietf.org]On
> Behalf Of Diego Caviglia
> Sent: Monday, November 10, 2003 8:17 AM
> To: ccamp@ops.ietf.org
> Subject: Source routed Notify message
> 
> 
> Hi all,
>               is there anyone interested in having source routed, may by
> means of standard ERO obj, Notify [RFC3473] message?
> 
> The motivation to use a source routing mechanism for Notify is avoiding
> OSPF convergence time during a network failure.
> 
> The scenario I've in mind is the following:
> 
>             A---------------B---------------C
>             |               |               |
>             |               |               |
>             |               |               |
>             D---------------E---------------F
>             |               |               |
>             |               |               |
>             |               |               |
>             G---------------H---------------H
> 
> Suppose there is a LSP (SDN/SONET) from H (Ingress) to A (Egress) and an
> unidirectional failure occours between C and F in the H-->A direction.
> Low layer mechanism (e.g AIS), informs A that a failure has 
> occourred.  TNE
> A wants to notify H about the failure but OSPF tables have not 
> been updated
> thus TNA A knows that "normal routing" will have some problem in 
> delivering
> the Notify to TNE H.
> 
> A source routed path calculated using Link diversity with respect to the
> failed LSP can avoid OSPF convergence time and inform efficently TNE H
> about the failure of the LSP.
> 
> That can be done either using the source route of the Ip header or using
> the ERO object.  The former has some limitation while the latter is
> larghely used in GMPLS.
> 
> Ragrds
> 
> Diego
> 
> 
> 
>