SIP protocol of gb28181

[RFC3261]

One 、SIP summary

Session initiation protocol (Session Initiation Protocal, SIP).SIP It is an application layer signaling control protocol , The main purpose is to IP Establish... In the network 、 Modify and release the application layer protocol of multimedia session . Its main applications include but are not limited to voice 、 news 、 video 、 Call control, etc . The participants of the session can use multicast （multicast）、 Mesh unicast （unicast） Or a mixture of both .

SIP Location of the agreement

SIP Follow HTTP equally , Belongs to the application layer protocol , So you can use UDP transmission ( More commonly used ), It can be the same as TCP transmission .

Two 、 Common terms

Business （transaction）: On the client side and on the server side , Contains the request sent from the first client to the server , adopt branch and cseq Parameter marks a transaction .

conversation (session)： It is a collection of multimedia senders and receivers . Can be understood as a call from the off hook 、 dial 、 conversation 、 Hang up and a series of signal actions .
session It was established after media exchange （ In exchange for SDP）

dialogue (dialog): A conversation is two that last for a while UA End to end... Between SIP Relationship . use call-ID,local tag ,remote tag（ other party tag） To mark a conversation .