From Forum Nokia Wiki

ID		Creation date	October 2008
Platform	S60 3rd Edition,	Devices	S60 3rd Edition devices
Category	VOIP	Subcategory	SDP

Basic concept of SDP

Session Description Protocol (SDP) is an application layer protocol used to define delivered audio and video format between nodes on Internet.The streaming data format is described in plain ASCII format.

Use of SDP

In SIP, SDP is used to describe multimedia communication sessions format during multimedia session initiation stage.SIP nodes use SDP to negotiate detail communication media type and format.After SIP nodes agree communication media type and format,they begin to use Real-time Transport Protocol (RTP) to exchange media data.

SDP will provide the following information.

1. Session Name and its purpose.
2. Time when the session is start
3. The media comprising the session
4. Detail to receive those media (eg,addresses, ports, formats, etc.)

A sample of SDP

v=0
o=username 2890844526 2890842807 IN IP4 10.47.16.5
s=SipSession
c=IN IP4 10.47.16.5
t=0 0
a=direction:both
m=video 49152 RTP/AVP 96
a=sendonly
a=rtpmap:96 H263-2000/90000
m=audio 57344 RTP/AVP 97
a=sendonly
a=rtpmap:97 AMR/8000

explanation: v=0:protocol version

o=username 2890844526 2890842807 IN IP4 10.47.16.5:originator and session identifier.

s=SipSession:name of this session.

c=IN IP4 10.47.16.5:connection information.

t=0 0:time when session is active.

a=direction:both m=video 49152 RTP/AVP 96 a=sendonly a=rtpmap:96 H263-2000/90000 m=audio 57344 RTP/AVP 97 a=sendonly a=rtpmap:97 AMR/8000 codecs information.

S60 SDP classes

CSdpDocument,CSdpOriginField,SdpCodecStringPool,SdpCodecStringConstants,CSdpConnectionField can be used to set SDP session as the above sample.