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PRACK/rel100 - Printable Version

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PRACK/rel100 - looserouting - 09-18-2014 10:28 PM

I had some problem with my phone T26P. it send PRACK retransmission even if it received a 200 OK response.(dunno if its a bug or it's caused by packet lost)

depending on the sip server this causes the server to send a 606 Not acceptable an the call was drop.

So i decided to turn off PRACK in the config menu.
I found the option "Retransmission" in Account-->Advanced. The describtions says "Enable/Disable PRACK transmission". But regardless of the choice i made the phone always sends "Supported: rel100". A SIP server could answer with "Require:rel100" in the response. So if deactivating PRACK the phone shouldn't send "Supported: rel100"

i am running but it also happend with

RE: PRACK/rel100 - James_Yealink - 09-19-2014 11:25 AM

Hi Looserouting,

For an analysis, can you please send pcap file, level 6 syslog, config.bin file to us.


RE: PRACK/rel100 - looserouting - 09-23-2014 05:50 PM

this is really simple to reproduce. just disable PRACK as I discribed and make a call.

You will see in the header "Supported: rel100". But that's not what you would expect. As I said before: the remote party could answer with "Required: rel100". So when PRACK is disabled "Supported: rel100" should be omitted.

RE: PRACK/rel100 - looserouting - 11-03-2014 04:09 AM

I don't have a yealink phone anymore. So I can't help with that. Sorry