[asterisk-dev] pjsip and timers configuration

Michael Maier m1278468 at mailbox.org
Sat Sep 5 16:18:02 CDT 2020

Hello all,

according [1], there are those options in pjsip regarding support of timers:


    forced - Alias of always

I'm wondering about their meanings.

- "No" seems to be clear. No timers support at all.

- "Always"? I have no idea. Therefore I tested it. I couldn't find any timers support mentioned in INVITE or 200 OK at all.

- "Required"? Same as "yes" - the only difference was the timer:require in asterisk's outbound Invite.

Is this the expected behavior, especially regarding "always"?

Another question:
I can see here the following (with timer=yes):
On *outbound* calls, the provider says in 200 ok: refresher is uas (means: provider). The first refresh coming in as update, the provider says: refresher is uac (that would be
asterisk) and asterisk acks it in the 200 ok. But the provider does send all following updates (always with uac as refresher). Asterisk itself doesn't send any update (I would expect
it - or is asterisk just not fast enough and provider is always faster? Min-SE is 900 and Session-Expires is 1800 - updates from provider are coming exactly each 900 s).

Is this the expected behavior?
I can't see this behavior on inbound calls. Here, refresher in 200 ok and following updates doesn't differ.


[1] https://wiki.asterisk.org/wiki/display/AST/Asterisk+17+Configuration_res_pjsip#Asterisk17Configuration_res_pjsip-endpoint_timers

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