sip sdp

I. Introduction to SDP protocol SDP is completely a session description format-it is not a Transport Protocol-it only uses different appropriate transport protocols, including session notification protocol (SAP) and Session Initiation Protocol (SIP), real-time stream protocol (RTSP), MIME extension protocol email and Hypertext Transfer Protocol (HTTP ). The

, the validity period of the URI address is determined by the Expires header field value. SIP Request Message instance: INVITE sip:0109@127.0.0.1:5060; User=phone sip/2.0 call-id:01e04633512400000@127.0.0.1 VIA:SIP/2.0/UDP 127.0.0.1:5061 from:to:contact:sip:010203@127.0.0.1:5061 Cseq:1 INVITE Max-forwards:70 Content-type:application/

caller that the caller is ringing (ringing). Route set: Routing set. A routing set is a sip or sips URI in order. These URIs describe the list of proxies that must go through to pass a request. A routing set can be adaptive because the header contains either Record-route (record routing) or dependency configuration. Server: Servers. A server is a network element that receives the request and processes the request and sends a response to the reque

is called an SDP message.The problem is that the SIP terminal (UA) may not know anything about Nat. Therefore, IP addresses contained in SDP usually use internal IP addresses, that is, IP addresses known by the SIP terminal. In this way, when the communication peer wants to communicate with the

collection string by the SDP user name, session ID, network type, address type, and address element. SIP transaction: a sip transaction receives an event on the client and server, including the first request sent from the client to the server and the last one (not 1xx) the server sends an end response to the client. If the request is an invite request and the fi

The original link (also reproduced) http://blog.csdn.net/yetyongjin/article/details/6881491. I have modified some typos. SIPWhat kind of problems do you encounter from the private network to the public network? 1. Address translation of the package.2. SIP address translation inside SIP messages.3. The RTP address translation in the SDP in the

To transfer media, you first have to establish a media conversation (session). Establishing a media session is actually a process of negotiating the media parameters of a session through the SDP Offer/answer Exchange. In SIP, the process of establishing a media session is usually first accompanied by the process of establishing a SIP dialog (Dialog), in which m

for different NAT types. L UPnP L external Query L stun L ALG Among them, the first three are obtained by the SIP client (including UA and proxy) by some means or protocol before the invite. The SIP client is required to provide additional support and is not applicable to all Nat methods. The ALG (Application Layer Gateway) is applicable to all Nat methods and does not require any additional support from t

What are the problems with SIP from private network to public network? Address translation of the package. SIP address Translation inside the SIP message. The RTP address translation in the SDP inside the SIP message. The existing structure of the network is complex,

SDP Protocol Introduction of SDP protocol The SDP is completely a session description format (corresponding to the RFC2327)-it is not a transport protocol-it uses only different appropriate transport protocols, including session Notification Protocol (SAP), Session Initiation Protocol (SIP), real-time Streaming Proto

The author's blog address: http://blog.sina.com.cn/samzhen1977 By Sam (zhufeng) sam_code@hotmail.com Service DiscoveryProtocol (SDP) provides a capability for applications to discover which service is available and the features of this service. Service Discovery Protocol (SDP or BluetoothSDP) in the Bluetooth protocol stack, applications in the Bluetooth environment have special meanings and find out which