[Users] TM : retransmission timers

[Jean-François SMIGIELSKI]

Hello,

I made strange observations about the intervals between retransmissions with the TM module.
In my experiments,  I used the default parameters for the TM module timers, and I  sent an INVITE that cannot receive answers (it has a well  known R-URI pattern that is forwarded to a place and port that nobody listen).

When reading RFC3261, I expected to see intervals between retransmissions of |500ms|1s|2s|4s|8s|16s|. 7 transmissions, during 32s.

But with OpenSER, (I have tested with the debian package 1.1.0-5 on a debian etch, and the cvs sources for 1.1.0 or 1.0.1compiled by myself), I can see intervals like <500ms, 2s, 4s, 4s,4s, ... until 26s are spent (9 sendings). The first interval is sometomes very short (40ms).

Altough I like the sequence of 4s separated transmissions, I do not know why the first interval is so short, and why there is no sending after 1s.

Did anybody observed such behaviours? Are they normal?

Thanks in advance!

JF Smigielski.


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