Session Initiation Protocol (SIP) is an Internet Engineering Task Force (IETF) standards text based signaling methodology that is used as the underlying protocol within the network to setup communication paths between endpoints.
SIP can initiate real-time, multimedia sessions that seamlessly integrate voice, data, and video.
SIP – Basic Syntax
Text based protocol
– Inspired by the HTTP protocol
Every message consists of:
– Starting line
– Request Line or Status Line; Terminated with CR+LF
– A number of headers
– One header per line; Each line terminated with CR+LF
– An empty line (CR+LF) following the last header
– Optionally, a message body
– Presence, type and length of the message body is indicated by the headers:
• Content-Type:
• Content-Length:
SIP – Basic Syntax – Example
INVITE sip:riza@rizademir.com SIP/2.0
Via: SIP/2.0/UDP pca.istanbul.com:5060;branch=z9hG4bK776asdhds
From: Alp <sip:alp@istanbul.com>;tag=1928301774
To: riza <sip:riza@rizademir.com>
Call-ID: 12345600@pca.istanbul.com
CSeq: 1 INVITE
Contact: <sip:alp@pca.istanbul.com:5060;transport=udp>
Content-Type: application/sdp
Content-Length: 147
v=0
o=Alp 2890844536 2890844536 IN IP4 pca.istanbul.com
s=-
c=IN IP4 200.201.202.203
t=0 0
m=audio 47172 RTP/AVP 97
a=rtpmap:97 PCMU/8000
a=sendrecv
The blog post titled “What is SIP” will be updated over time. You can stay tuned to receive the latest updates. Rıza Demir
