Subject: [Megaco] MID used to identify sender

From: Inger Bohlbro <[email-masked]>
Date: Thu, 24 Jun 2004 15:21:48 +0200

Hi

I have a question regarding the Message Identifier (MID).

H.248.1 states
"A H.248.1 entity (MG/MGC) must consistently use the same MID
in all messages it originates for the duration of control
association with the peer (MGC/MG)".

Is it allowed for a MG to use the MID to check if the message
is received from the MGC with which contol association is
obtained, i.e. compare MID in received messages with the
MID received in the ServiceChange response ?

This could be especially relevant when running over UDP, in
order to discard messages received from "old" associations.

It could also be relevant during a failover situation
to be able to distinguish between messages from an "old"
MGC and messages from the MGC at which a ServiceChange request
is outstanding. Requests received from the "new" MGC should
be answered with error code 505 if received before the
ServiceChange response.

However, in draft-ietf-megaco-callflows-03.txt there is an
example in section 3.1.1 where the MID used in ServiceChange
response is [216.33.33.61]:2944 and in all following messages
it is [216.33.33.61]:25000. The ServiceChange response contains
the ServiceChangeAddress = 25000 parameter, but never the less
the two MID's are not identical.

Regards
Inger Bohlbro

-- 
Inger Bohlbro                  System Developer, M. Sc. 
Ericsson Telebit A/S           phone:  +45 89 38 52 65
Skanderborgvej 232             fax:    +45 89 38 51 01
DK-8260 Viby J, Denmark        e-mail: [email-masked]

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From: Christian Groves <[email-masked]>
Date: Fri, 25 Jun 2004 12:33:24 +1000

Hello Inger,

Where there are differences between the Call Flows and the H.248.1 
recommendation, H.248.1 takes precedence.

A note for everyone: DO NOT BASE AN IMPLEMENTATION on the 
<draft-ietf-megaco-callflows-03.txt> draft. These flows have quite a few errors 
and misassumptions and do not represent a definitive guide to the use of H.248.1.

Regards, Christian

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From: Tom Taylor <[email-masked]>
Date: Fri, 25 Jun 2004 13:55:27 -0400

Let's go one further on this.  If you identify errors, please notify the author. 
It's time we got this document cleaned up and posted as an Informational RFC.