T310 timer and PROGRESS
cngroves at bigpond.net.au
Mon Jan 23 18:10:54 EST 2006
I had a look at Q.931 as the precurser to H.225 to see what the
intention was there. Whilst not in the core specification there was a
description of the behaviour in an annex described Private Network
"M.220.127.116.11 In-band information provided to the physical
PINX at the originating interface
Any progress indications shall be conveyed towards the physical PINX at
the originating interface.
On receipt of the Progress description No. 1 or No. 8 in the PROGRESS or
ALERTING message, the physical PINX at the originating interface shall
switch through in the backward direction to the allocated B-channel in
order to enable transfer of in-band tones/information, and stop timer
T310, if running."
M.18.104.22.168 In-band information provided by the physical PINX
at the destination interface
During call establishment, after the first message received in response
to the SETUP message, on receipt of a Progress indicator information
element with a Progress description No. 1 or No. 8 in the PROGRESS or
ALERTING message, the public network shall switch through in the
backward direction to the allocated B channel in order to enable in-band
tones/information provided from the physical PINX at the destination
interface to the calling user, stop timer T310, if running, and if
progress description No. 1 or No. 8 was received in the PROGRESS message
while T310 was running, restart timer T310.
The public network shall transfer the Progress indicator information
element towards the preceding PINX."
Paul E. Jones wrote:
> Recently, I asked what should happen when an endpoint receives a
> PROGRESS message indicating that there are in-band tones and
> announcements. Should the T310 timer be stopped? H.225.0 seems to be
> silent on this, but it would certainly seem that it should be stopped.
> Should we stop the timer or should the timer continue to run? It will
> expire in short order (assuming a default value), which suggests the
> timer ought to be terminated and T301 started.
> I would appreciate your input on this.
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