----------------------
SDP in initial INVITE:
----------------------
v=0.
o=- 3584698679 0 IN IP4 xxx.xxx.xxx.xxx.
s=Cisco SDP 0.
c=IN IP4 xxx.xxx.xxx.xxx.
t=0 0.
m=audio 39220 RTP/AVP 8 0 18 101 102 103 104 105 4 106 3 107 108 109 125 99 100.
a=rtpmap:101 G729a/8000.
a=rtpmap:102 G726-16
a=rtpmap:103 G726-24/8000.
a=rtpmap:104 G726-32/8000.
a=rtpmap:105 G7231-H/8000.
a=rtpmap:106 G7231-L/8000.
a=rtpmap:107 G729b/8000.
a=rtpmap:108 G7231a-H/8000.
a=rtpmap:109 G7231a-L/8000.
a=rtpmap:125 CLEARMODE/8000.
a=rtpmap:99 telephone-event/8000.
a=fmtp:99 0-15.
a=rtpmap:100 X-NSE/8000.
a=fmtp:100 192-194,200-202.
a=X-sqn:0.
a=X-cap: 1 audio RTP/AVP 100.
a=X-cpar: a=rtpmap:100 X-NSE/8000.
a=X-cpar: a=fmtp:100 192-194,200-202.
a=X-cap: 2 image udptl t38.


-------------------------------
SDP in 200 OK from Asterisk 11:
-------------------------------
v=0.
o=root 1110185050 1110185050 IN IP4 xxx.xxx.xxx.xxx.
s=Asterisk PBX 11.5.1.
c=IN IP4 xxx.xxx.xxx.xxx.
t=0 0.
m=audio 19682 RTP/AVP 8 0 104 3 101.
a=rtpmap:8 PCMA/8000.
a=rtpmap:0 PCMU/8000.
a=rtpmap:104 G726-32/8000.
a=rtpmap:3 GSM/8000.
a=rtpmap:101 telephone-event/8000.
a=fmtp:101 0-16.
a=ptime:20.
a=sendrecv.