Subject: v10 review: text for optional commands

From: Nancy-M Greene <[email-masked]>
Date: Thu, 23 Sep 1999 15:26:53 -0500

The latest draft is still missing the text that explains that a command in a
transaction should be able to be marked so that if it fails, it does not
cause further execution of commands in the transaction to stop.

An example of when you would use this is when you have an Add command, then
a Modify command that sends out the calling Id, then an Audit command. If
the Modify fails, you still want the Audit to be executed.

In the ABNF, this can be accomplished by allowing a command to be prefixed
with "0-". This marks the command as optional. The MG can execute it or not,
and if it does execute it and the command fails, it returns the error code,
but it still continues executing commands in that transaction.

I propose that the following text be added to the Megaco/H.248 protocol:

Section 8.2.2. TransactionReply

Current text:
--------
Each of the Response parameters represents a return value as mentioned in
Section 7.2, or an error descriptor if the command execution encountered an
error. Commands after the point of failure are not processed and, therefore,
Responses are not issued for them.
----------
Proposed text:
----------
Each of the Response parameters represents a return value as mentioned in
Section 7.2, or an error descriptor if the command execution encountered an
error. Commands after the point of failure are not processed and, therefore,
Responses are not issued for them.

An exception to this occurs if a command has been marked as optional in the
Transaction request. If a command is marked as optional, the MG has the
choice of executing it or not, and if it does execute it, it returns the
Response, or Error. If the optional command does generate an error, the
transaction still continues to execute, so the Reply would, in this case,
have Responses after an Error.
-----------

Of course the ABNF needs to be updated to allow "o-", or "O-" to occur
before a command.

Nancy

--------------------------------------------------------------------------
Nancy M. Greene
Internet & Service Provider Networks, Nortel Networks
T:514-271-7221 (internal:ESN853-1077) E:[email-masked]