[H.323] h323-url url parameters

Chip Sharp chsharp at CISCO.COM
Tue Jul 17 16:46:54 EDT 2001


My understanding of preGrantedARQ call leg is that unsolicited IRR is the
ONLY RAS message that may be sent on such call leg.

To be honest this understanding based more on memory and intuition than on
something written in the standard.
The only written thing that I was able to find and that somehow "clarifies"
the issue is the following paragraph from  H.225.0 (explanation of
irrFrequencyInCall subfield of preGrantedARQ field in RCF:
irrFrequencyInCall - This indicates the frequency, in seconds, of IRR
messages sent to the gatekeeper when the endpoint is in one or more calls.
If it is not present, the gatekeeper does not want unsolicited IRR messages.
When the endpoint is sending these IRR messages, the call reference value
shall be made unique for the terminal, as it would have been generated in an
Admission Request. However, this is not a "normal" CRV, and cannot be reused
for further communication (DRQ, IRQ or BRQ). The call identifier shall be
the same as used in the call signaling channel messages for the related
So, does this mean (DRQ, IRQ or BRQ) cannot be sent or they should be sent
with "normal" CRV?


-----Original Message-----
From: Horvath Ernst [mailto:ernst.horvath at SIEMENS.AT]
Sent: Tuesday, July 17, 2001 5:07 AM
Subject: AW: CRV Blues


the call-ID is the real means to tie together all messages related to the
same call.

Regarding your specific questions:

For a GK routed call, the GK "knows" about the call even in the case of
pre-granted admission, and can of course send BRQ/IRQ. The CRV used for
these RAS messages can be the same as in SETUP.

For a directly routed call with pre-granted admission, the GK is not
immediately aware of the call (periodic IRQs for all calls is one way to
obtain this knowledge eventually). However, the endpoint can always send RAS
messages, e.g. BRQ or IRR. For these RAS messages it will use an arbitrary
locally unique CRV and, more important, the same globally unique call-ID.

Ernst Horvath
Siemens AG

> -----Ursprüngliche Nachricht-----
> Von: Paul, Manoj [mailto:mpaul at TRILLIUM.COM]
> Gesendet am: Dienstag, 17. Juli 2001 01:39
> An: ITU-SG16 at mailbag.cps.INTEL.COM
> Betreff: CRV Blues
>  Hi All,
>   I have a couple of question related to the use of RAS CRV.
> Consider an endpoint EP1 has pre-granted admission and sends
> SETUP with
> 225CRV1 to
> GK. If GK subsequently sends a BRQ/IRQ for this call, what
> RASCRV is uses in
> these
> messages. Would RASCRV be same as 225CRV1 ?
> Secondly, is it expected that GK can potentially send BRQ/IRQ
> for a call for
> which it gave
> pre-granted admission to an endpoint?
> Any pointers are appreciated.
> regards
> Manoj Paul.
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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