improving the routing efficiency of sip instant message sip 即時傳訊之繞送效能研究
DESCRIPTION
Improving the Routing Efficiency of SIP Instant Message SIP 即時傳訊之繞送效能研究. adviser ： Quincy Wu speaker ： Wenping Zhang date ： 2008.03.13. Outline. Introduction Messaging Schemes Page-mode SIP/SDP Session-mode MSRP SIP Server Message syntax Method SDP Structure Drawback MSRP - PowerPoint PPT PresentationTRANSCRIPT
Improving the Routing Efficiency of SIP Instant MessageSIP 即時傳訊之繞送效能研究
adviser ： Quincy Wu speaker ： Wenping Zhangdate ： 2008.03.13
2
Outline Introduction Messaging Schemes
Page-mode SIP/SDP
Session-mode MSRP
SIP Server Message syntax Method
SDP Structure
Drawback MSRP
Method Future Work Reference
3
Introduction 1/2
4
Introduction 2/2
5
Messaging Schemes 1/2 Page-mode messaging
That track only individual messages can be described. Uses the SIP Method MESSAGE for transmitting data.
User 1 User 2
6
Messaging Schemes 2/2 Session-mode messaging
Messaging that is part of a "session" with a definite start and end. The new proposed model by SIMPLE work group using MSRP
Protocol.
MSRP
Proxy
User 1 User 2
SIP SIP
7
Session Initiation Protocol (SIP) A signaling protocol
The setup, modification, and tear-down of multimedia sessions
SIP + SDP Describe the session characteristics
Separate signaling and media streams
8
SIP Server
Proxy servers Handle requests or forward requests to other serv
ers Can be used for call forwarding, time-of-day routin
g, or follow-me services
9
UA 1<sip:[email protected]>
UA 2<sip:[email protected]>
Proxy Serversip:server.work.com
(1) [email protected] (2) INVITE
(3) 100 Trying(4) 180 Ringing
(5) 180 Ringing
(6) 200 OK(7) 200 OK
(8) [email protected] (9) ACK
Connection (Media Stream)
(10) [email protected] (11) BYE
(12) 200 OK(13) 200 OK
10
SIP Messaging Syntax
Text-based Similar to HTTP Disadvantage – more bandwidth consumption
SIP messages Message = start-line
*message-header CRLF [message-body]
11
12
SIP for Instant Messaging
The IETF working group – SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE)
A new SIP method –MESSAGE (RFC 3428) This request carries the actual message in a
message body. A MESSAGE request does not establish a SIP
dialog.
13
UA 1 UA 2Proxy Server
(1) MESSAGE(2) MESSAGE
(3) 200 OK(4) 200 OK
(5) MESSAGE(6) MESSAGE
(7) 200 OK(8) 200 OK
14
The Session Description Protocol (SDP) The Most Common Message Body
Be session information describing the media to be exchanged between the parties
SDP, RFC 2327 (initial publication) SIP uses SDP in an answer/offer mode
An agreement between the two parties as to the types of media they are willing to share
RFC 3264 (An Offer/Answer Model with SDP) To describe how SDP and SIP should be used together
15
The Structure of SDP SDP simply provides a format for describing session
information to potential session participants. Text-based Protocol The Structure of SDP
Session Level Info Name of the session Originator of the session Time that the session is to be active
Media Level Info Media type Port number Transport protocol Media format
16
17
Drawback 1/2
Proxy server
Bob
Mary
18
Drawback 2/2
19
The Message Session Relay Protocol (MSRP) MSRP is a text-based, connection-oriented protocol
for exchanging arbitrary (binary) MIME content, especially instant messages.
The exchange is carried by some signaling protocol, such as the Session Initiation Protocol (SIP). This allows a communication user agent to offer a messaging session as one of the possible media-types in a session.
SIP can use an offer/answer model to transport the MSRP URIs for the media in SDP.
20
Alice Bob
INVITEINVITE sip:[email protected] SIP/2.0To: <sip:[email protected]>From: <sip:[email protected]>;tag=786Call-ID: 3413an89KUContent-Type: application/sdp
c=IN IP4 atlanta.example.comm=message 7654 TCP/MSRP *a=accept-types:text/plaina=path:msrp://atlanta.example.com:7654/jshA7weztas;tcp
200 OKSIP/2.0 200 OKTo: <sip:[email protected]>;tag=087jsFrom: <sip:[email protected]>;tag=786Call-ID: 3413an89KUContent-Type: application/sdp
c=IN IP4 biloxi.example.comm=message 12763 TCP/MSRP *a=accept-types:text/plaina=path:msrp://biloxi.example.com:12763/kjhd37s2s20w2a;tcp
ACK
MSRP Session
21
MSRP communication primitives 1/2 SEND Method
Be used to deliver a complete message or a chunk (a portion of a complete message).
src: www.cs.columbia.edu/~hgs/teaching/ais/slides/sip-suthan.ppt
22
MSRP communication primitives 2/2 REPORT Method
It report on the status of a previously sent message, or a range of bytes inside a message.
23
UA 1 UA 2Proxy Server
(SIP) INVITE(SIP) INVITE
(SIP) 200 OK(SIP) 200 OK
(SIP) ACK(SIP) ACK
(MSRP) SEND(MSRP) 200 OK
(MSRP) SEND(MSRP) 200 OK
(SIP) BYE(SIP) BYE
(SIP) 200 OK(SIP) 200 OK
24
Future Work
Joins the MSRP mechanism in existing SIP phone (Linux – Linphone).
How solves MSRP passes through NAT the question?
25
Reference RFC 3261 - SIP: Session Initiation Protocol
http://www.ietf.org/rfc/rfc3261.txt
RFC 3428 - Session Initiation Protocol (SIP) Extension for Instant Messaging http://www.ietf.org/rfc/rfc3428.txt
RFC 2327 - SDP: Session Description Protocol http://www.ietf.org/rfc/rfc2327.txt
RFC 3264 - An Offer/Answer Model with the Session Description Protocol (SDP) http://www.ietf.org/rfc/rfc3264.txt
The Message Session Relay Protocol http://www.ietf.org/rfc/rfc4975.txt