Subject: Annex G Examples - UPDATE

From: Nancy-M Greene <[email-masked]>
Date: Wed, 29 Sep 1999 10:07:55 -0500

Brian et al,  are preparing the next version of the protocol, to come out
early next week I think - it will contain editorial changes. Before then, I
would like to have more people review Annex G. In particular I would like to
have the multimedia examples reviewed.

Since the v10 version, I have incorporated a few semantic changes. In
particular, instead of sending down almost empty Local and Remote
descriptors from the MGC to the MG, I added a NetworkType parameter to
LocalControl. Then, when the MG has the IP address and port information, it
sends it to the MGC in the Reply.

Please find the Sept 28th version of Annex G at:

ftp://standards.nortelnetworks.com/megaco/docs/wash99/AnnexGSept28.doc  and
.pdf

The examples have been recompiled using the ABNF compiler we have (thanks
Abdallah), so they are syntactically correct as well.

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

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From: Emre Gunduzhan <[email-masked]>
Date: Thu, 30 Sep 1999 17:51:32 -0400

Nancy, I think the following parts need correction in the first
example in Annex G:

1) In step 12 the MGC specifies two codecs, G723 and PCMU. MG1
replies in step 13 by choosing BOTH of them in the LocalDescriptor,
but it should have chosen only one value from the list (section 7.1.2).

2) In steps 12-14, the preferred/chosen packetization (20ms) is
inconsistent with the preferred/chosen codec (G.723), whose frame
size is 30ms.

3) It looks like step 18 is not needed, since ringing signal was
already sent in step 14.

I also have a question related to (1). How would the MGC ask using
different codecs for the encoder and the decoder? We probably need two
parameters, PreferredEncoders and PreferredDecoders, in addition to
PreferredCodecs?

Emre

--
Emre Gunduzhan
Signal Processing Group, Nortel Networks
Phone: (301)250-3653   Fax: (301)921-0161