No SDP body only one. but packet like this
INVITE sip:device-200@sip:1.21.10.2:45437;rinstance=07f88c423145358e;transport=UDP SIP/2.0
Record-Route: <sip:sip.myservice.com:5068;nat=yes;ftag=as1be940e5;lr=on>
Via: SIP/2.0/UDP sip.myservice.com:5068;branch=z9hG4bKca7d.2d16143316e23fac46bf686bb41780b3.2
Via: SIP/2.0/UDP 17.74.28.7:50600;branch=z9hG4bK22c67800;rport=50600
Max-Forwards: 70
CSeq: 102 INVITE
User-Agent: Asterisk PBX 12.6.1
Date: Thu, 23 Oct 2014 19:27:54 GMT
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH, MESSAGE
Supported: replaces, timer
Content-Type: application/sdp
Content-Length: 1044
v=0
o=root 1195474335 1195474335 IN IP4 2.10.39.16
s=Asterisk PBX 12.6.1
c=IN IP4 2.10.39.16
t=0 0
a=ice-lite
m=audio 30614 RTP/SAVPF 8 3 0 101
a=rtpmap:8 PCMA/8000
a=rtpmap:3 GSM/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ptime:20
a=maxptime:150
a=sendrecv
a=rtcp:30615
a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:OY72ZDHa+E3avlHwschrdBMe00qDfkN0BUyOxT1C
a=setup:actpass
a=fingerprint:sha-1 07:3D:B4:B0:0E:0D:87:39:C3:83:10:E2:B8:B8:2C:0C:0D:59:EF:4C
a=ice-ufrag:Wudfwh08
a=ice-pwd:VoamuFVRrAXOhUaeD6tA3PcXhndL
a=candidate:8jYonvAy1KGkAdP3 1 UDP 213070