Re: [Serusers] INVITE timeout

summary: I think you need to special case timers for outbound calls not to interfere with timer logic in the other domain for inbound calls. Way a) modifiable timers (takes a piece of work on code, see a separate email), way b) stateless forwarding for outbound calls without the possibility of accounting.

as for b) the idea is simple, you keep no state for request (use forward as opposed to t_relay), you just forward back and forth like an IP router, and that's it. SER will not need and/or be able to to wipe the state from memory and cancel a transaction prematurely. The limitation is that stateless processing is mutualy exclusive with accounting. If you wish to account calls to other domains, you need to keep requests and replies in memory to correlate them to generate accounting records. If you keep something in memory, you need to set up timer to clean it if it is there for too long and takes too much place.

-jiri

At 03:56 PM 2/8/2004, Greg Fausak wrote:

I have an INVITE timeout problem.

My SIP layout includes:

        +---------------+
        | EXTERNAL PSTN |
        | SIP SERVERS   |
        +---------------+
                |
                |
        +---------------+
        | MAIN INCOMING |
        | SIP SERVER    |
        +---------------+
          |           |
          |           |
+------------+      +-----------------+
| SIP SERVER |      | SIP SERVER      |
| DOMAINA.com|      | OtherDom.com    |
+------------+      +-----------------+
    |                     |
    |                     |
+----------+             +---------+
| customerA|             |otherCust|
+----------+             +---------+

I hope the ASCII drawing worked!

Calls come in from the top down. The MAIN INCOMING server uses internal ENUM to deliver the call to the correct domain server. Once delivered to that server, if the customer does not answer his phone before an INVITE timeout occurs the call is forwarded to voicemail.

This works great when the call is from an external PSTN server. It also works great if a user in DOMAINA.com calls another user in DOMAINA.com.

I am experiencing difficulty when a user in DOMAINA.com calls a user in OtherDom.com. The SER at DOMAINA.com recognizes that INVITE is going to a foreign domain, and it t_relays() the INVITE to the MAIN INCOMING SER. It then gets t_relayed() to OtherDom.com where the call is delivered.

The problem is both use the same INVITE timer, so the TIMEOUT on DOMAINA.com occurs *before* the TIMEOUT on OtherDom.com, which means that the call is not delivered to voicemail.

Any ideas?

---greg

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-- Jiri Kuthan http://iptel.org/~jiri/