[Freeswitch-users] Responding to INVITE with 180 vs 183

[Ben Hood]

Many thanks for your suggestions.

Though I have not yet solved the end to end issue, I have broken the
problem down into smaller parts that I have been successively
debugging and verifying. Along the way I have discovered a number of
signalling bugs in our setup.

The most pertinent issue I have discovered is IP fragmentation problem
in the firewall of the PEER. So after correcting the MTU on the link,
I was able to get an INVITE to arrive at the remote PEER.

So I think I might be on the way to discovering the underlying issue.

On Thu, Feb 12, 2015 at 12:16 PM, Lucas Castro <lucasmcastro at gmail.com> wrote:
> I could notice it is missing the ACK package from your PEER. Maybe its
> sending it to the wrong place, maybe its not sending it at all.
> FreeSWITCH will retry 200 OK over and over 'cause it expects an ACK in order
> to continue.
>
> here are some tips:
>
> Enable sip trace on the PEER side to check whether its sending ACK or not.
> Compare 200 OK (SDP) from FreeSWITCH in each scenario. Maybe there are
> differences between them.
>
> On Wed, Feb 11, 2015 at 5:05 PM, Ben Hood <0x6e6562 at gmail.com> wrote:
>>
>> I think you may well have a point.
>>
>> I've spent days on this issue and I'm beginning to narrow it down by
>> breaking the bridging down into the individual legs. I've also been
>> able to establish RTP flow with the same originator by proxying the
>> INVITE to a non-FS user agent (i.e. a phone registered with Kamailio).
>>
>> I didn't want to leave this post dangling without a some kind of
>> closure, so I thought I'd just post this status update.
>>
>> On Tue, Feb 10, 2015 at 8:33 PM, Michael Jerris <mike at jerris.com> wrote:
>> > I doubt it has anything to do with 180vs183.  Check for nat issues in
>> > the trace that isn't working.
>> >
>> >> On Feb 10, 2015, at 2:55 PM, Ben Hood <0x6e6562 at gmail.com> wrote:
>> >>
>> >> Hi all,
>> >>
>> >> I'm wondering what influences Freeswitch's signalling response when it
>> >> responds to an INVITE.
>> >>
>> >> In some instances it appears to follow this sequence:
>> >>
>> >> Peer -> INVITE (SDP) -> FS
>> >> Peer <- 100 <- FS
>> >> Peer <- 183 (SDP) <- FS
>> >> Peer <- 200 (SDP) <- FS
>> >> Peer -> ACK -> FS
>> >>
>> >> Which leads to a successful bridge between two legs.
>> >>
>> >> But in other instances it appears to follow the sequence:
>> >>
>> >> Peer -> INVITE (SDP) -> FS
>> >> Peer <- 100 <- FS
>> >> Peer <- 180 (SDP) <- FS
>> >> Peer <- 200 (SDP) <- FS (1st attempt)
>> >> Peer <- 200 (SDP) <- FS (2nd attempt)
>> >> ....
>> >> Peer <- 200 (SDP) <- FS (nth attempt)
>> >> ....timeout
>> >>
>> >> I'm not 100% sure whether the remote peer (itself a SIP trunk) doesn't
>> >> like the 100/180/200 sequence (as opposed to 100/183/200), so I need
>> >> to find that out for myself.
>> >>
>> >> But I am wondering what factors influence Freeswitch's decision of
>> >> what sequence signals to send in response to an INVITE.
>> >>
>> >> Any pointers appreciated,
>> >>
>> >> Ben
>> >
>> >
>> >
>> > _________________________________________________________________________
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>> >
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>> >
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>> _________________________________________________________________________
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>> consulting at freeswitch.org
>> http://www.freeswitchsolutions.com
>>
>> Official FreeSWITCH Sites
>> http://www.freeswitch.org
>> http://confluence.freeswitch.org
>> http://www.cluecon.com
>>
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>
>
>
>
> --
> Atenciosamente,
> Lucas Castro
>
> _________________________________________________________________________
> Professional FreeSWITCH Consulting Services:
> consulting at freeswitch.org
> http://www.freeswitchsolutions.com
>
> Official FreeSWITCH Sites
> http://www.freeswitch.org
> http://confluence.freeswitch.org
> http://www.cluecon.com
>
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