1 Dec
2012
1 Dec
'12
4:35 a.m.
Hi Daniel,
Yes I am using forward() because I thought it would be the fastest solution.
I guess I was lead on by the dispatcher documentation saying it can be used
statelessly, so I tried to do the whole route script stateless.
However, I've recently been looking at t_relay and in particular
t_check_trans() and I think that might be the answer...
I do think it would be great if the ds_select_dst/domain functions
performed a lookup in the hash table for non-INVITEs and set the right
destination though.
Cheers,
Richard
On 30 November 2012 08:31, Daniel-Constantin Mierla <miconda(a)gmail.com>wrote;wrote:
Hello,
by stateless dispatcher do you mean using forward() to send out the INVITE?
Cheers,
Daniel
On 11/28/12 1:40 PM, SIP Mailing-list wrote:
Further edit:
Actually I tried using ds_select_dst to forward the ACK on the unconfirmed
(unanswered; 603 Decline) call but it routed to another destination.
My work-around involves using ds_next_dst to send the ACK to *all*
destinations.
Does anyone know if there is a way to fix this behaviour?
Any help is much appreciated!
Cheers,
Richard
On 27 November 2012 20:12, SIP Mailing-list <sip(a)racitup.com> wrote:
Hi guys,
I wonder if someone could sanity check something for me.
I currently have a simple load balancer set up using algorithm 10 (call
load distribution) from the dispatcher module. I'm using Record-Routing so
that I can clear down the call load record at the end of the call.
Everything looked like it was working okay until I just spotted a problem
that I think might be a bug. It's to do with ACKs to non-200 responses.
In a normal call, the flow goes:
UAC Proxy UAS
1 INVITE -->
2 INVITE-->
3 <-- 200 OK
--- ds_load_update()
4 <-- 200 OK
5 ACK -->
6 ACK -->
Now between step 3 and 4 the proxy runs ds_load_update which according to
the documentation "set internal state to confirmed for the call load" entry
in the internal call state store. This means the proxy knows where to send
the ACK at step 5 because it is safely in the call state store so you can
use ds_select_dst again on the ACK to get it to the right place. Works fine!
Now consider the non-200 case:
UAC Proxy UAS
1 INVITE -->
2 INVITE-->
3 <-- 603 Decline
--- ds_load_unset()
4 <-- 603 Decline
5 ACK -->
6 ACK --> ???
Between step 3 and 4 the proxy is supposed to run ds_load_unset() which
unconditionally removes the call from the call state store. Now when the
ACK comes in at step 5, the proxy has no record of the call and so doesn't
know where to send the ACK. This results in retried Declines and ACKs.
Broken :-(
If the proxy doesn't run ds_load_unset() on the 603 response, is there
some kind of timer that will cause the call to be removed from the call
state store on unconfirmed calls?
I don't think I can run ds_load_unset on the ACK because there's nothing
in the ACK that tells me it is because of a 603, rather than a 200.
Edit: actually there is! The Route header is present on the 200 ACK, but
*not* on the 3xx to 6xx ACK. Maybe I can use loose_route... Anyway, any
thoughts would be appreciated!
Cheers,
Richard
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