[OpenSIPS-Users] T.38 detection/redirect in OpenSIPS

[Stanisław Pitucha]

On 17/03/10 17:15, Matthew S. Crocker wrote:
> UA -> PROXY 200 Ok (SDP/G711)
> PROXY -> PSTN  200 Ok (SDP/G711)
> ** RTP Established between UA & PSTN  (mediaproxy/rtpproxy ??) **
> ** Gateway detects fax tone and attempts to REINVITE to T.38 **
> PSTN -> PROXY INVITE (SDP/T38)
> PROXY -> PSTN  180 Trying
> PROXY -> UA  INVITE (SDP/T38)
> UA -> PROXY  488 Not Acceptable Here
> ** PROXY Error route rewrite URI **
> PROXY -> ASTERISK   INVITE (SDP/T38)

Your plan will fail around here. The dialog was already established
between the UA and PSTN. The invite which you have not has both "to" and
"from" tags set and anyone seeing it will respond - "I don't know
anything about this dialog, go away". Not much you can do about it
without B2BUA functionality. To solve the problem "properly", you will
need a separate call in this moment.