asterisk users - May 2004 - MeetMe conference delay increasing

I've just noticed a strange behaviour with a MeetMe conference.

I have a pair of phones (GS BT102) on my desk, and dialled both of them
into a conference on speakerphone. If I spoke or made a sound, I heard
it replayed from both speakers together a split second later, as
expected.

I went away for about 15 minutes, leaving the conference running.

When I came back any sound I made came back out of the speakers, not
immediately, but with about a 2 second delay or more!

I hung up one of the phones and redialled the conference. Now a sound
was relayed out of the redialled phone immediately, but still delayed on
the other phone. Hanging up that other phone and redialling restored the
immediate timing on that phone too.

I was using the iLBC codec on both phones, so I disabled ilbc in
sip.conf and then retried the test using alaw instead. Leaving the
conference running for an hour didn't introduce any appreciable delay.

So the increasing delay must be due to the iLBC codec in either the
phone or in Asterisk.

For a final test, I re-enabled iLBC in the phones, and changed the iLBC
frame size from 20ms to 30ms. I then repeated the test. The delay still
increased over time, but not as quickly.

Comments?

Cheers
Tony
-- 
Tony Mountifield
Work: tony@softins.co.uk - http://www.softins.co.uk
Play: tony@mountifield.org - http://tony.mountifield.org