[Spce-user] UDP packet size

Andreas Granig agranig at sipwise.com
Wed Mar 5 07:15:16 EST 2014


After investigating a pcap off the records:

Well, I don't see any fragmentation issue, and there is nothing wrong in
the call flow either, apart from the fact that it's just an
INVITE/407/ACK without a second attempt with credentials.

I would expect the client now to send another INVITE, this time with an
Authorization header.

Where did you do the trace? On the SPCE machine? Can you somehow figure
out if the client is actually sending another INVITE and it's just not
ending up on the SPCE, or if the client doesn't send another INVITE at
all in this scenario (maybe by means of client log-files or tracing on
the client host/phone)?


On 03/05/2014 11:38 AM, Andreas Granig wrote:
> Hi,
> On 03/05/2014 09:29 AM, Nikita Stashkov wrote:
>> Below are two INVITE messages (Bria iPhone). Both calls are to voicemail, so codec is G.711. 
>> In the first some codecs are disabled and call is ok:
> <snip>
>> So the question - what is maximum packet size (or Content-Lengt) for UDP?
>> While using TLS I have no problems.
> The limit is 64k, as far as I know, so way above your size. You're
> probably running into some UDP fragmentation issue (although typical MTU
> sizes are around 1400 byte).
> You'd need to check if the message really arrives at the system. Try to
> capture a trace with tcpdump (without filtering on the port, just filter
> on udp to catch fragmented packets) and see if it arrives at the system
> in full.
> Also the trace would tell us if that's really the problem, or if there
> is some other issue.
> Andreas
> _______________________________________________
> Spce-user mailing list
> Spce-user at lists.sipwise.com
> http://lists.sipwise.com/listinfo/spce-user

More information about the Spce-user mailing list