Subject: Telcordia SG16: Comments on 8.1.2 regarding ContextIDs in H.248

From: Selvam Rengasami <[email-masked]>
Date: Thu, 27 Jan 2000 09:13:46 -0500

Section 8.1.2 of H.248 (White Paper, Megaco Version 12) describes uses for only
two of the possible values for contextID: "null

? and "unspecified".  Actually,
the protocol [either ASN.1 or ABNF] does not make reference to the use of these
values.  It simply indicates how these are coded.  Clear requirements or
guidelines are needed for how each of these is to be used.  For example, how is
the "choose" value to be used and how/why is it different than using the
"unspecified" value? Notice that  the "choose" wildcard is used for
TerminationIDs to request the MG to allocate a TerminationID in the case of an
ephemeral termination.

Since TerminationIDs use a value of "choose" to request the MG to allocate a
value in the case of an ephemeral termination (i.e., one that does not exist),
contextIDs should also use the value of "choose" when requesting the MG to
allocate a value. Section 8.1.2 should be modified so that the word
"unspecified" is replaced with the word "choose".

Section 3.5 of a Telcordia Technologies contribution to SG 16 (which can be
found at
ftp://standard.pictel.com/avc-site/Incoming/telcordia-h248-misc-cmts.DOC )
provides a proposal for clarifying this issue.

-Selvam Rengasami
Telcordia Technologies
Tel:  +1 732 758 5260
E-mail:  [email-masked]