13 May
2013
13 May
'13
11:37 a.m.
Hi,
Does kamailio support PRACK method ? Any configuration change is needed?It appears
Kamailio does not like the PRAK when increasing Cseq. Here is the call flow:
A send INVITE --> Kamailio --> proxy the packet to BB send 180 Ringing -->
Kamailio -> proxy the packet to AA send PRAK (increase Cseq) --> Kamailio -->
proxy the packet to BB send 200 OK --> Kamailio -> proxy the packet to AKamailio
re-send 180 Ringing to A
Thanks,AS
13 May
13 May
11:41 a.m.
PRACK is an in-dialog/sequential request, which will be relayed like
other. So, Kamailio relays it in the same way that it supports any
sequential request. Is it not necessary for a SIP proxy to do anything
specific to support PRACK.
The UAC should not be increasing the CSeq when sending a PRACK. My
guess is that it is the UAS which doesn't like it, rather than
Kamailiio. From RFC 3262 Section 3 ("UAS Behavior"):
A matching PRACK is defined as one within the same
dialog as the response, and whose method, CSeq-num, and
response-num in the RAck header field match, respectively,
the method from the CSeq, the sequence number from the CSeq,
and the sequence number from the RSeq of the reliable
provisional response.
-- Alex
On 05/13/2013 11:37 AM, Alex Solt wrote:
Hi,
Does kamailio support PRACK method ? Any configuration change is needed?
It appears Kamailio does not like the PRAK when increasing Cseq.
Here is the call flow:
A send INVITE --> Kamailio --> proxy the packet to B
B send 180 Ringing --> Kamailio -> proxy the packet to A
A send PRAK (increase Cseq) --> Kamailio --> proxy the packet to B
B send 200 OK --> Kamailio -> proxy the packet to A
Kamailio re-send 180 Ringing to A
Thanks,
AS
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--
Alex Balashov - Principal
Evariste Systems LLC
235 E Ponce de Leon Ave
Suite 106
Decatur, GA 30030
United States
Tel: +1-678-954-0670
Web: http://www.evaristesys.com/, http://www.alexbalashov.com/
11:49 a.m.
Just to confirm:Kamaili is forwarding the PRAK packet. However, it seems the kamailio
ignore the Cseq increase within the PRAK and therefore it ignore the 200 Ok after that.
Then, Kamailio re-send 180 again.
Thank,AS
Date: Mon, 13 May 2013 11:41:09 -0400
From: abalashov(a)evaristesys.com
To: sr-users(a)lists.sip-router.org
Subject: Re: [SR-Users] Does Kamailio support PRACK ?
PRACK is an in-dialog/sequential request, which will be relayed like
other. So, Kamailio relays it in the same way that it supports any
sequential request. Is it not necessary for a SIP proxy to do anything
specific to support PRACK.
The UAC should not be increasing the CSeq when sending a PRACK. My
guess is that it is the UAS which doesn't like it, rather than
Kamailiio. From RFC 3262 Section 3 ("UAS Behavior"):
A matching PRACK is defined as one within the same
dialog as the response, and whose method, CSeq-num, and
response-num in the RAck header field match, respectively,
the method from the CSeq, the sequence number from the CSeq,
and the sequence number from the RSeq of the reliable
provisional response.
-- Alex
On 05/13/2013 11:37 AM, Alex Solt wrote:
Hi,
Does kamailio support PRACK method ? Any configuration change is needed?
It appears Kamailio does not like the PRAK when increasing Cseq.
Here is the call flow:
A send INVITE --> Kamailio --> proxy the packet to B
B send 180 Ringing --> Kamailio -> proxy the packet to A
A send PRAK (increase Cseq) --> Kamailio --> proxy the packet to B
B send 200 OK --> Kamailio -> proxy the packet to A
Kamailio re-send 180 Ringing to A
Thanks,
AS
_______________________________________________
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
sr-users(a)lists.sip-router.org
http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
--
Alex Balashov - Principal
Evariste Systems LLC
235 E Ponce de Leon Ave
Suite 106
Decatur, GA 30030
United States
Tel: +1-678-954-0670
Web: http://www.evaristesys.com/, http://www.alexbalashov.com/
_______________________________________________
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
sr-users(a)lists.sip-router.org
http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
11:51 a.m.
On 05/13/2013 11:49 AM, Alex Solt wrote:
Just to confirm:
Kamaili is forwarding the PRAK packet. However, it seems the kamailio
ignore the Cseq increase within the PRAK and therefore it ignore the 200
Ok after that. Then, Kamailio re-send 180 again.
Incorrect on all counts.
1) Kamailio does not "ignore" anything in the PRACK;
2) Kamailio cannot "ignore" 200 OKs; it simply passes all replies that
it receives. It is not a recipient of 200 OKs. Its job is to pass them
back to the user agent that is.
3) Kamailio likewise cannot originate replies, so it does not re-send
the 180. The UAS does.
In other words, the problem you are seeing is between the endpoints that
are calling each other through the proxy. Kamailio is just a dumb,
disinterested messenger here.
-- Alex
--
Alex Balashov - Principal
Evariste Systems LLC
235 E Ponce de Leon Ave
Suite 106
Decatur, GA 30030
United States
Tel: +1-678-954-0670
Web: http://www.evaristesys.com/, http://www.alexbalashov.com/
11:44 a.m.
Alex Solt writes:
Does kamailio support PRACK method ? Any configuration
change is
needed?
my understanding is that prack is like any on-dialog request and does
not need any special handling on kamailio. i have not had any problems
with pracks and there is nothing prack specific in my config. this is
without dialog module which i don't know anything about.
-- juha
4051
days inactive
4051
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4 comments
3 participants
participants (3)
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Alex Balashov -
Alex Solt -
Juha Heinanen