T23G Transfer Sent using incorrect transport.

[JMComstock]

Hello,

This applies to 'Yealink SIP-T23G 44.80.0.80'

I have 100's of T23G that fail to send the REFER sip message using the correct transport.

The T23G registers via TCP correctly. Calls are initiated and received correctly over the TCP connection. However, when the phone needs to transfer an existing call either in Attended or Unattended mode, it tries to send the SIP REFER message over UDP.

For the call that it is transferring, it correctly places the call on hold via the TCP connection:

Here is the INVITE that places the call on hold:

Jan 18 19:41:30 sua [567]: NET <5+notice> [000] reusing connection (to dest=2xx.2xx.1xx.84:5080)
Jan 18 19:41:30 sua [567]: NET <6+info > [000] socket node:2xx.2xx.1xx.84 , socket 19 [pos=0], connected
Jan 18 19:41:30 sua [567]: DLG <5+notice> [000] Message sent: (to dest=2xx.2xx.1xx.84:5080 len=1226)
Jan 18 19:41:30 sua [567]: DLG <6+info > [000]
Jan 18 19:41:30 sua [567]: DLG <6+info > [000] INVITE sip:3xx7xx6717@2xx.2xx.1xx.84:5080;transport=tcp SIP/2.0^M
...
Jan 18 19:41:30 sua [567]: DLG <6+info > [000] a=sendonly^M

The correct OK and ACK follow.

The phone then issues the REFER via UDP!:

Jan 18 19:41:33 Log [608]: TALK<6+info > BlindTransfer Number[102]
Jan 18 19:41:34 Log [608]: CUIT<6+info > RequestTransfer: [102]

Jan 18 19:41:34 sua [567]: DLG <5+notice> [000] Message sent: (to dest=2xx.2xx.1xx.84:5080 len=562)
Jan 18 19:41:34 sua [567]: DLG <6+info > [000]
Jan 18 19:41:34 sua [567]: DLG <6+info > [000] REFER sip:3xx7xx6717@2xx.2xx.1xx.84:5080;transport=tcp SIP/2.0^M
Jan 18 19:41:34 sua [567]: NET <5+notice> [000] ===>>>> UDP socket 2xx.2xx.1xx.84:5080: send 562 bytes

This is causing a major issue for us as we have 100's of the T23G out in the field.

This does not happen on T22, and T48 phones.

Thanks for looking at this!

[Karl_Yealink]

Would you please send the syslog to me?
If possible, please also send the T22 or T48 syslog to me.

You can send the file to my email(karl@yealink.com). So I can give you respond asap and the file won't be public.
It's better you can add the link of this post in the email.