SIP Session Description Protocol, SDP.
SDP 1998 RFC2327. 8 , 2006 , RFC4566.
SDP . IP , . ?
SDP
SDP SIP . . SIP INVITE, IP Asterisk sngrep:
INVITE sip:74996491913@192.168.x.xxx:5061;transport=UDP SIP/2.0 Via: SIP/2.0/UDP 80.xx.yy.zz:5060;branch=z9hG4bK-524287-1-MThkZjMzNzMyXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX;rport Via: SIP/2.0/UDP 80.xx.yy.zz:5077;branch=z9hG4bK-XXXXXXXXXXXXXXXX;rport=5077 Max-Forwards: 69 Record-Route: <sip:80.xx.yy.zz:5060;lr;transport=UDP> Contact: <sip:80.xx.yy.zz:5077> To: <sip:74996491913@80.xx.yy.zz> From: <sip:7925XXXXXXX@80.xx.yy.zz>;tag=qdpxhe2avyyjcqfn.o Call-ID: fb9909e8fYYYYYYYYYYYYYYYYYYYYYY CSeq: 479 INVITE Expires: 300 Allow: INVITE, ACK, BYE, CANCEL, INFO, SUBSCRIBE, NOTIFY, REFER, MESSAGE, OPTIONS, UPDATE Content-Disposition: session Content-Type: application/sdp User-Agent: Sippy P-Asserted-Identity: <sip:7925XXXXXXX@80.xx.yy.zz> Remote-Party-ID: <sip:7925XXXXXXX@80.xx.yy.zz>;party=calling h323-conf-id: 4133864240-4217115111-2706418710-XXXXXXXXX Portasip-3264-action: offer 1 cisco-GUID: 4133864240-4217115111-2706418710-XXXXXXXXX Content-Length: 278 v=0 o=Sippy 1011212504475793896 1 IN IP4 80.xx.yy.zz s=- c=IN IP4 80.xx.yy.zz t=0 0 m=audio 57028 RTP/AVP 0 8 18 101 a=rtpmap:0 PCMU/8000 a=rtpmap:8 PCMA/8000 a=rtpmap:18 G729/8000 a=fmtp:18 annexb=yes a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-15 a=sendrecv

, SIP SDP . , Content-Type
, SDP .
SDP
SDP :
- ;
- , ;
- ;
- ;
- ;
. : <> = <>. 1 .
v= | v=0 | |
o= | o=<_> <_> <> <_> <_> <>. o=Sippy 1011212504475793896 1 IN IP4 80.xx.yy.zz (IN - , , IP4 - , IPv4; |
|
s= | ("-"), ; | |
c= | ; | : c=<_> <_> <>. IN IP4 80.xx.yy.zz . IN/IP4 . |
t= | : t=<_> <_>. , , , . t=0 0 | |
m= | , | m=<_> <> <> <_>. - m=audio 57028 RTP/AVP 0 8 18 101 , ( video, ), 57028, , RTP/AVP, RTP Audio and Video Conferences with Minimal Control, RFC3551. , 0 G.711 uLaw, 8 G.711 ALaw, 18 G.729. , G.711 uLaw, G.711 ALaw, G.729. 101 , DTMF. |
a= | a=<> a=<><>. SDP . . |
, k=
, , i=
, . a=
:
rtpmap | a=rtpmap:<> <_>/<_> [/<_>]. , , m= . , a=rtpmap:0 PCMU/8000, G.711 - U - 8000 . |
sendrecv | a=sendrecv , - . , (sendonly), (recvonly) (inactive); |
ptime | a=ptime:<_> RTP - ( ). , RTP - ; |
fmtp | a=fmtp:<> <_> , , (VAD) ; |