Re: On TD26 - Fast TCS and M/S negotiation in H.323v4
5.8.6.2/Q.931: When a SETUP or RELEASE message is received which has one or more mandatory information elements with invalid content, a RELEASE COMPLETE message with cause No. 100, “invalid information element contents” shall be returned."
My understanding of this statement is that it is meant to cover Q.931 elemements themselves, NOT UUIE content. As far as Q.931 is concerned, the User-user information element can be coded in whatever way we want. It is an ISDN thing that was carried over in H.225.0. So, my take is that this section is completely irrelevant to the H.245 tunnelling (or in fact H.245 in general). Also, it talks about a message (RELEASE) that is not even supported in H.225.0.
Francois, The UUIE _is_ a Q.931 IE, 5.8.6.2/Q.931 does not exclude this IE, and neither H.225.0 or H.323 address the issue of how to handle a UUIE--or any other IE, for that matter--with invalid content, therefore the behavior defined in Q.931 is normative for H.323. _All_ of Q.931 is an "ISDN thing," so what's your point? Finally, there is much in Q.931 that H.323 does not reference, but that does not invalidate the parts of Q.931 that H.323 references. Paul Long Smith Micro Software, Inc. -----Original Message----- From: Francois Audet [mailto:audet@NORTELNETWORKS.COM] Sent: Thursday, June 01, 2000 7:34 AM To: ITU-SG16@MAILBAG.INTEL.COM Subject: Re: On TD26 - Fast TCS and M/S negotiation in H.323v4
5.8.6.2/Q.931: When a SETUP or RELEASE message is received which has one or more mandatory information elements with invalid content, a RELEASE COMPLETE message with cause No. 100, “invalid information element contents” shall be returned."
My understanding of this statement is that it is meant to cover Q.931 elemements themselves, NOT UUIE content. As far as Q.931 is concerned, the User-user information element can be coded in whatever way we want. It is an ISDN thing that was carried over in H.225.0. So, my take is that this section is completely irrelevant to the H.245 tunnelling (or in fact H.245 in general). Also, it talks about a message (RELEASE) that is not even supported in H.225.0. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv@mailbag.intel.com
In Q.931, the user-user IE is typically optional, so the clause that Paul Long's been quoting wouldn't apply. However, since H.323 makes the UUIE mandatory, it *does* apply in the case under discussion. I think that the statement contained in TD-26, that it preserves backwards compatibility, is completely wrong. The correct statement should have been that it doesn't break implementations known to the authors. I agree with Paul that we should try to develop a better solution. Regards, Dave Walker SS8 Networks Ottawa, Canada Paul Long wrote:
Francois,
The UUIE _is_ a Q.931 IE, 5.8.6.2/Q.931 does not exclude this IE, and neither H.225.0 or H.323 address the issue of how to handle a UUIE--or any other IE, for that matter--with invalid content, therefore the behavior defined in Q.931 is normative for H.323.
_All_ of Q.931 is an "ISDN thing," so what's your point?
Finally, there is much in Q.931 that H.323 does not reference, but that does not invalidate the parts of Q.931 that H.323 references.
Paul Long Smith Micro Software, Inc.
-----Original Message----- From: Francois Audet [mailto:audet@NORTELNETWORKS.COM] Sent: Thursday, June 01, 2000 7:34 AM To: ITU-SG16@MAILBAG.INTEL.COM Subject: Re: On TD26 - Fast TCS and M/S negotiation in H.323v4
5.8.6.2/Q.931: When a SETUP or RELEASE message is received which has one or more mandatory information elements with invalid content, a RELEASE COMPLETE message with cause No. 100, invalid information element contents shall be returned."
My understanding of this statement is that it is meant to cover Q.931 elemements themselves, NOT UUIE content. As far as Q.931 is concerned, the User-user information element can be coded in whatever way we want. It is an ISDN thing that was carried over in H.225.0.
So, my take is that this section is completely irrelevant to the H.245 tunnelling (or in fact H.245 in general). Also, it talks about a message (RELEASE) that is not even supported in H.225.0.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv@mailbag.intel.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv@mailbag.intel.com
participants (3)
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Dave Walker -
Francois Audet -
Paul Long