[SIPForum-discussion] Doubts in SIP

[Spencer Dawkins]

I'm not sure I'd agree with the description of SDP as a "session protocol" - it's a session DESCRIPTION protocol, and Internet "sessions" really don't have much in common with ISO sessions (that do things like recover from transport layer failures, which SDP certainly does not do.

SIP must be one of the most successful layer violations in protocol history, but people like Dean Willis will tell you that SIP was designed by people who didn't understand layering until it was too late - so SIP has application-level retransmissions that duplicate transport-level retransmissions, etc. 

Spencer
  ----- Original Message ----- 
  From: Nitin Kapoor 
  To: Sathya 
  Cc: discussion at sipforum.org 
  Sent: Wednesday, January 27, 2010 12:10 PM
  Subject: Re: [SIPForum-discussion] Doubts in SIP


  Sathya,



  SIP definitely follows OSI reference model. SIP is said to be “Application layer” protocol because it closely resembles the semantics of application layer protocols like HTTP.



  SIP: combination of application and session layers

  SDP: session and presentation

  TCP/USP: Transport

  IP: Network



  Apart from please go through the below link to check out the codec detail.



  http://www.voipthink.com/codec/codecs.php



  Thanks,

  Nitin Kapoor




  2010/1/26 Sathya <thinksathya at gmail.com>

    Hello Everybody .....

     As i am new to SIP kindly clear my below doubts ...

    1. What layer of OSI belongs to SIP and the reason for it.
    2. Different types of codecs and their bandwidth usages and the type of environment it can be used .


    Thanks

    Sathya.


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