Subject: [Megaco] Text encoding format

From: "Gillian Wang" <[email-masked]>
Date: Mon, 4 Oct 2004 13:56:59 +1000

Dear Megaco members,

My questions here are regarding the information provided in Annex B and
Annex C of the H.248.1 v2 standard.

In H.248.1 Annex B.2, text encoding format is specified. There is another
hexadicimal octet coding specified in B.3. Can you please advise where this
hexadecimal octet coding should be used for the megaco message structure?

Are the attributes defined in Annex C for binary encoding only? if yes, how
to set these attributes for the text encoding? like Gain, jitterbuff,
Silencesupp or encrptkey, etc. If not, can we use the PropertyID and values
for the text encoding?

Thanks for the clarification.

Regards
Gillian

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From: Christian Groves <[email-masked]>
Date: Mon, 04 Oct 2004 16:36:54 +1000

G'Day Gillian,

The hexadecimal format should be used whereever Octet String encoding is 
defined. See H.248.1 sect 12.2, "Octet String: A number of octets. See Annex A 
and B.3 for encoding"

In H.248.1v3 we clarified the use of Annex C to be:
"The referencing of Annex C properties follows the PackageID/PropertyID 
structure; however Annex C is not in itself a package. Annex C is considered to 
have PackageID 0x0000 for binary encoding and “anxc” for text encoding. For text 
encoding of H.248.1, Annex C shall only be used in the case that the required 
property is not already defined by a package or represented by SDP. The nesting 
of one Annex C property inside another is forbidden."

Regards, Christian

---

From: "Gillian Wang" <[email-masked]>
Date: Mon, 4 Oct 2004 17:45:18 +1000

Christian, thanks for the clarification.

For the second question, based on my understanding of the Megaco protocol,
properties are related to the packages; parameters are grouped into
descriptors. In that case, I thought that the Annex C might specify the
parameters which belonged to different descriptors, although some not to
existing descriptors. However, your answer provides a different
implementation approach of these parameters/properties. Thanks for that! By
the way, are there any clear definitions on parameters and properties from
implementation's point of view?

Regards
Gillian

-----Original Message-----
From: Christian Groves [mailto:[email-masked]]
Sent: Monday, 4 October 2004 4:37 PM
To: Gillian Wang
Cc: [email-masked]
Subject: Re: [Megaco] Text encoding format

G'Day Gillian,

The hexadecimal format should be used whereever Octet String encoding is
defined. See H.248.1 sect 12.2, "Octet String: A number of octets. See Annex
A
and B.3 for encoding"

In H.248.1v3 we clarified the use of Annex C to be:
"The referencing of Annex C properties follows the PackageID/PropertyID
structure; however Annex C is not in itself a package. Annex C is considered
to
have PackageID 0x0000 for binary encoding and “anxc” for text encoding. For
text
encoding of H.248.1, Annex C shall only be used in the case that the
required
property is not already defined by a package or represented by SDP. The
nesting
of one Annex C property inside another is forbidden."

Regards, Christian