RE: Flooding using LMP extensions

["Ong, Lyndon" <LyOng@Ciena.com>]

Hi Vishal,

I haven't been following this discussion closely, but
I think you are right in distinguishing routing from
signaling as functions in the control plane.  Some of
the confusion may be in the term SNPP link, in ITU
terminology this is a representation of connectivity
between different subnetworks for routing purposes,
so for example it may include multiple link connections 
that share the same characteristics.

Knowing the state of an SNPP link would not tell you the
state of individual connections using the SNPP link,
which would be a signaling function.

Cheers,

Lyndon

-----Original Message-----
From: Vishal Sharma [mailto:v.sharma@ieee.org]
Sent: Thursday, June 19, 2003 6:28 PM
To: rick king; Roberto Albanese; ccamp@ops.ietf.org
Subject: RE: Flooding using LMP extensions 


Rick,

Thanks for the pointer. I now have a better idea of what you
were referring to earlier.

Actually, there is no conflict between the discussion we're currently
having and the ITU description. (One (the ITU description below)
refers to, what I would call, "routing related" updates in the control
plane, while the other (the discussion we're having) refers to,
what I would call, "sigaling related" updates in the control plane.)

Except that in the rabbat-draft, the so called "signaling" (or,
more accurately, fault notification) is achieved via flooding.

The ITU description you've provided below refers to _routing related_
activity in the control plane. (That is, if a link state changes, the
control plane -- RC, RDB, etc. -- have to learn about it and make the
required
updates.)
In fact, this is what will happen in an IP-controlled transport
network also. The routing information and related databases _will_,
eventually, be updated. (And, at that time, one may
more optimally route those circuits that have been switched to recovery
paths in the meantime.)

We, however, are talking about recovery here. This includes steps that
have to occur _in the interim_ to ensure that traffic flow is not
disrupted (or disrupted as little as possible). So there has to
be a way to inform the affected nodes of the failure for them to
take action.
_This_ is what we've been discussing on this thread.

I don't think the ITU documentation is implying at all
that the routing-related updates be the means of fault
notification.

-Vishal