[Spce-user] SIP UDP packet fragmentation breaking calls

[Daniel Grotti]

Hi Marco,
SPCE does not fallback in TCP unfortunately.
you should reduce the MTU by removing headers or you should be able to
rebuild your fragmented packets at the final destination.

--
Daniel Grotti
VoIP Engineer


Sipwise GmbH
Europaring F15 | 2345 Brunn am Gebirge, Austria | www.sipwise.com

On 09/21/2015 11:27 PM, Marco Teixeira wrote:
> Hi there,
> 
> I might have stumbled upon the issue described here (but without any ALG
> in the middle, just for example, as i can't pass any sensitive info here)
> 
> I'm seeing fragmented SIP packets when the final gateway sends OPTION
> back over 2 NGCP CE and over to a final farm of SIP servers...
> 
> The call is established correctly and only when the OPTIONs don't get
> ACK, the call drops within 10 seconds (always).
> 
> So, according to the test on that link, trancript below:
> (..) If a request is within 200 bytes of the path MTU, or if it is larger
>    than 1300 bytes and the path MTU is unknown, the request MUST be sent
>    using an RFC 2914 [43] congestion controlled transport protocol, such
>    as TCP. (...)
> 
> Shouldn't SIPWISE activate TCP or whatever to avoid this ? 
> How did you guys solve this ? 
> (no, TCP on all calls is really asking for trouble on the call volume
> i'm aimming for)
> 
> 
> Best regards
> Marco
> 
> 
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