Subject: Topology Defaults For Fan-Out Connections

From: "Sean Leahy" <[email-masked]>
Date: Tue, 17 Jul 2001 10:32:14 +0100

Any answers ?
---------------------- Forwarded by Sean Leahy/MAIN/MC1 on 17/07/2001 10:30
---------------------------

CN=Andrew Russell-laing/OU=MAIN/O=MC1@MCMAIN on 12/07/2001 10:20:40

 To:       [email-masked]                                    
                                                              
 cc:       (bcc: Sean Leahy/MAIN/MC1)                         

 Subject:  Topology Defaults For Fan-Out Connections          

Hi,

I have a question on the conventions for the format and defaults for the usage
of the Topology Descriptor.

The default setting for a toplogy is "Bothway" between all terminations within a
context.

When handling a Fan-Out connection for tones we have a situation of wishing to
add a new ephemeral
termination to an existing context.  In this situation we want the topology to
be Oneway between the
fixed termination and the new ephemeral termination, and Isolate between all of
the existing ephemeral
terminations and  the new ephemeral termination.

The existing default rules would mean having  to specify a topology triple for
every ephemeral termination and
the new ephemeral termination in the context, which is not a good idea for
fan-out connections of up to 50
ephemeral terminations.

Alternatives are :-

a.   Introduce a proprietary change into our Media Gateway software to change
the topology default rules for
     fan-out connections such that the default is Isolate between all
ephemerals.

b.   Use a partial specification of the existing ephemeral terminations in the
topology descriptor.

     e.g.   { ATM*, $, Isolate }

     where     ATM*      represents a partial specification of all ephemeral
terminations within the context.

          $    represents the new ephemeral termination to be chosen and added
to the context.

          Isolate   indicates the topology is isolate between all ephemerals in
the context.

     Is option b. considered to be proprietary in relation to the H.248 protocol
rules.

     Does anyone have any alternative solutions to overcome this problem. If not
which of
     options a. and b. is considered the best solution.

     Thanks.

Andrew Russell-Laing
Marconi

---

From: Christian Groves <[email-masked]>
Date: Wed, 18 Jul 2001 12:05:44 +1000

You can use 2 topology triples:

topology ([*,new_euphemeral or ?, ISOLATE],[physical,new_euphemeral or
?,ONEWAY])

Wildcards are valid in the topology descriptor i.e. ? and *.

Cheers, Christian