Subject: [Idr] Operational Message and Multiple-Sessions

From: David Freedman <[email-masked]>
Date: Tue, 3 Apr 2012 08:34:36 +0000

Folks, 

Now that draft-ietf-idr-operational-message is a WG document,
we could do with your valuable input!

We'd like to put in some wording concerning dealing with OPERATIONAL
messaging
over multiple sessions, where we define these as sessions between the same
pair
of router identifiers.
(This could cover the multisession and non-multisession cases)

We would like to make sure that only one session at a time is transmitted
over
(but not preclude this happening in the future, perhaps looking at use
cases with fast control failover) and allow for messages to be received
over multiple sessions (but suggest that the implementation if it does
this, de-duplicate the received information)

For the moment, we're not concerned about which OPERATIONAL message type
is used, since we're decoupling the request from the session type
(for example, we request the AFI/SAFI in the STATE queries),
even in the case of the MUP/DUP/DUMP messages, it shouldn't matter which
session the bad data was transmitted over, only that we get the relevant
information back to the other side (feel free to should loudly if you
think this
decoupling is a bad idea, we think from a simplicity PoV this would be
appropriate)

We're toying with adding wording like this:

------------

Multiple Sessions:

Where multiple sessions are established between the same peer, OPERATIONAL
messages SHOULD be transmitted over a single ESTABLISHED session only,
at any one time.

OPERATIONAL messages MAY be received over multiple ESTABLISHED sessions
from the peer, an implementation SHOULD ensure that no duplicate
information 
is reported to the operator of the system.

------------

We could add the caveat that the transmit session is the oldest
established, in order
to gain some symmetry (do people feel that symmetry is important?)

Dave.