[Spce-user] Udp to Tcp sig generates big mtu making the messages to fail

[Daniel Grotti]

Hi,
A pcap trace would help, anyway, it looks like an Asterisk behavior:

http://www.spinics.net/lists/asterisk/msg123908.html

Do you have a pcap to analyze the re-invite's MTU ?
And don't see such a lot of headers, just a couples od Record-Route and
Via, SDP also doesn't contain any additional lines.


Daniel




On 04/27/2014 10:19 AM, Cosmin Nistor wrote:
> Hello list,
> 
> New to the list - maybe i could get an opinion on an issue i am facing
> using a setup with Sipwise CE.
> Using 2.8, 3.0 versions, tested on the 3.2.1 on a test machine, the same.
> 
> Setup and problem description( see attached file):
> 
> - running Sipwise in the front doing sig( tcp) to uac and sig udp to
> asterisk + rtp and an Asterisk in the back doing sig udp.
> - uac1 calls uac 2, the calls gets answered, uac2 sends bye;
> - when bye is received by asterisk it sends an invite back( strange
> behaviour to me, but since asterisk is a b2bua may be legit to try to
> get the media back if there are any further steps to pass in the
> dialplan before sending the final bye);
> - Sipwise receives the invite from asterisk (udp) and passed the invite
> to uac( tcp) < here the trouble occours, the invite is a large packet
> that gets fragmented; the result is that down the line the uac does not
> ack the re-invite, so the call gets stuck.
> - using the same scenario but for the call leg Sipwise-uac using udp or
> tls i see the same call flow but the mtu of frames is less than 1500 =>
> packets are not fragmented => calls end ok.
> 
> I attach a ngrep trace to show the issue, a pcap contains sensitive
> information( ip, usernames).
> 
> The approach could be to stripe down the size of the packets, been
> trying to toggle parameters in sems white/blacklist but could not find a
> working solution > if i could find some suggestions would be appreciated.
> 
> Thanks and regards,
> 
> Cosmin
> 
> 
> 
> 
> 
> 
> 
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