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Transcription

1 E1-E2 E2 CFA Session Initiation Protocol

2 AGENDA Introduction to SIP Functions of SIP Components of SIP SIP Protocol Operation Basic SIP Operation

3 Introduction to SIP SIP (Session Initiation Protocol) is a signaling protocol used to create, manage and terminate sessions in an IP based network. It is a standard (RFC 3261) put forward by Internet Engineering Task Force (IETF).

4 Functions of SIP User location User availability User capabilities Session setup Session management

5 USER LOCATION

6 Components of SIP Client Server Proxy Server: Redirect Server: Registrar: Rout call request Return new location for request Maintain mapping from Name to Address

7 Proxy Server 2. Invitation to a session for anu@ Invitation to a session for SIP: anu@ company.com

8 Redirect Server SIP Redirect Server at company.com 1.Invitation to a session for SIP: anu@ company.com 2.Try at anu@ Invitation to a session for anu@

9 Registrar

10 SIP Protocol Operation Request Response

11 SIP Protocol Operation SIP Request Format Request Line Several Headers Empty Line Message Body SIP Response Format Status Line Several Headers Empty Line Message Body

12 SIP Request Format Request Line Several Headers Empty Line Message Body

13 SIP Request Format Request Line: Method Request URI Protocol Version Method : Indicate Type of Request INVITE, ACK, OPTIONS, BYE, CANCLE, REGISTER Request URL: Next Hop where request is to be routed Protocol Version : at present 2.0 INVITE sip: anu@company.com SIP/2.0

14 METHODS Command INVITE ACK BYE CANCEL OPTIONS REGISTER INFO Meanings Invites a user to a call Acknowledgement is used to facilitate reliable message exchange for INVITEs Terminates a connection between users Terminates a request, or search, for a user. It is used if a client sends an INVITE and then changes its decision to call the recipient. Solicits information about a server's capabilities. Registers a user's current location Used for mid-session signaling

15 SIP Response Format Status Line Several Headers Empty Line Message Body

16 SIP Response Format Status Line: Protocol Version Status Code Reason Phrase Status Code: Response of a request from 100 to 699 Reason-phrase A textual description of the outcome Could be presented to the user SIP/ Ringing

17 Status Code Response Code Description Example 1xx 2xx 3xx Informational Request received, continuing to process request Success Action was successfully received, understood and accepted. Redirection Further action needs to be taken in order to complete the request 180 Ringing 181 Call is being forwarded 200 OK 300 Multiple choices 302 Moved temporarily 4xx 5xx 6xx Client Error Request contains bad syntax or cannot be fulfilled at this server Server Error Server failed to fulfill an apparently valid request Global failure Request is invalid at any server 404 Not found 408 Request timeout 503 Service unavailable 504 Version not supported 600 Busy everywhere 604 Does not Exist anywhere

18 SIP Headers General Header To Header Request Headers Subject header Response headers Retry after header Entity Header Content- Length

19 INVITE sip: SIP/2.0 Via: SIP/2.0/UDP pc33.server1.com; branch=z9hg4bk776asdhds Max-Forwards: 70 To: user2 <sip: From: user1 Call-ID: CSeq: INVITE Contact: Content-Type: application/sdp Content-Length: 142

20 Basic SIP Operation

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