Automating Google Workspace (GWS) & more with Apps Script
Session Initiation Protocol - In depth analysis
1. CMPE 208 FALL 2008 PROJECT
Chinmay Padhye
Amit More
Abhishek Sharma
Nihar Dandekar
SIP: SESSION INITIATION PROTOCOL
2. INTRODUCTION
Developed originally as MULTIPARTY MULTIMEDIA
SESSION CONTROL IN 1999 -- RFC 2543 (SIPv1)
Latest revision RFC 3261 thru 3265 in June 2002 (SIPv2)
A powerful alternative to H.323 protocol
Is used for:
Initiating SESSIONS of multimedia over the Internet
transport session description from caller to callees
Change of parameters in mid-session
Terminate the session
3. INTRODUCTION
LINEAGE :
OSI Model – Layer 6 (Session Layer)
TCP/IP Model – Layer 5 (Application Layer)
Protocols supported:
RSVP
RTP
RTCP
RTSP
SAP
SDP
4. INTRODUCTION
Applications:
IP PBX
IP TELEPHONEY
INSTANT MESSEGING
INTERNET CONFERENCING
Features:
Uses the client – server model
Both the client and server can be on the same platform
Uses the concept of intelligent endpoint
5. DISTRIBUTED FUNCTIONALITY
De-centralization permits more functionality within each component.
Changes made to specific components have a minor impact on the rest
of the system. It is possible to connect one SIP phone to another with an
Ethernet cable & make calls between the sets without the aid of any
other server modules.
The other system components become useful when the network
requires more than two phones.
6. SIP - ENTITIES
SIP uses the following main Entities:
USER AGENT CLIENT
USER AGENT SERVER
PROXY SERVER
REDIRECT SERVER
REGISTRAR / LOCATION SERVER
10. SIP - METHODS
INVITE initiate call
ACK confirm final response
BYE terminate (and transfer) call
CANCEL cancel searches and “ringing”
OPTIONS features support by other side
REGISTER register with location service
INFO mid-call information (ISUP)
PRACK provisional acknowledgement
SUBSCRIBE subscribe to event
NOTIFY notify subscribers
REFER ask recipient to issue SIP request (call transfer)
11. SIP – REQUEST & RESPONSES
In text format
Look very similar to HTTP/1.1
Requests and responses are similar except for first line
Requests and responses can contain in there message
bodies
ASCII
HTML
SESSION DESCRIPTION
13. AUTHENTICATION & ENCRYPTION
SIP supports a variety of approaches:
End to end encryption
Hop by hop encryption
End to end encryption implemented using proxy servers that
form a tunnel between peers after authentication
Responds to INVITEs with 407 Proxy-Authentication Required
14. TEST BED
User Agent Client (UAC)
- Xlite
- 3CX
- SJphone
User Agent Server
- 3CX
- Hamachi
Packet analyzer
- Wireshark
15. TEST CASES
Soft-phone registration
Simple call setup
Call accepted
Call ignored
Soft-phone unregistered
Call forwarding
To voice mail
To extension
Call forking
2 way parallel call forking
3 way parallel call forking
Secure call connection via HAMACHI server
41. CONCLUSION
SIP is:
Relatively easy to implement
Gaining vendor and carrier acceptance
Very flexible in service creation
Extensible and scalable
Appearing in products right now
SIP provides its own reliability mechanism & is therefore
independent of the packet layer and only requires an
unreliable datagram service
42. REFRENCES
[1] http://faq.programmerworld.net/voip/voip.htm
[2] http://groups.google.com/group/SJSUee284/files
[3] http://ezinearticles.com/?The-SIP-Advantage&id=270970
[4] Internet Telephony based on SIP
SMU - Dallas
April 28, May 1, 2000
Henry Sinnreich, MCI WorldCom
Alan Johnston, MCI WorldCom
[5]http://books.google.com/books?hl=en&lr=&id=VMP6gCBazzIC&oi=fnd&pg=PR17&dq=project+on+call+flow+using+SIP+protocol&ots=EtmKee0_M3&sig=bjqG
[6] Evaluating SIP Proxy Server Performance
Erich M. Nahum, John Tracey, and Charles P. Wright
IBM T.J. Watson Research Center
Hawthorne, NY, 10532
fnahum,traceyj,cpwrightg@us.ibm.com
[7] Session Initiation Protocol (SIP) and other Voice over IP (VoIP) protocols and applications Henrik Ingo1
[8] http://www.3cx.com/phone-system/
[9] http://en.wikipedia.org/wiki/Session_Initiation_Protocol
[10] http://tools.ietf.org/html/rfc3261
[11] http://www.counterpath.com/x-lite.html
[12] http://www.counterpath.com/assets/files/191/X-Lite3.0_UserGuide.pdf
[13] http://www.qgpop.net/2003fukuoka/papers/A7-3.pdf
[14] http://en.wikipedia.org/wiki/Session_Initiation_Protocol
[15] Carrier Grade VoIP - Daniel Collins – McGraw-Hill – NETWORKING eBOOK
[16]http://www.radvision.com/NR/rdonlyres/0AFA30DF-DAD6-461D-943C-ED33F3E7ABD8/0/SIPServerTechnicalOverviewWhitepaper.pdf
[17] http://en.wikipedia.org/wiki/Hamachi
[18] http://www.cmpe.sjsu.edu/~fclin/
