[SIPForum-discussion] What's the info contained in the SDP?

[Clint Perry]

Technically 183 can carry SDP as well...

SDP is the Audio Setup for the device sending the SDP....

That defines the ports and IPaddress for the SIP "Speaker" to send the audio.

A will send to B its codecs, IP and Ports that he is "going" to use
for that session


B does the same


-CP

On Tue, Jul 14, 2009 at 9:01 AM, devibalas
sdevibala<msg4devibala at gmail.com> wrote:
>
> Hi Mike,
>    As far as ur call is concerned the SDP info can either be carried in 180
> ringing or in 200OK. The SIP server will send back the SDP info of the
> called party(B) to the calling party(A). The server either has this info
> stored(Purely IP) or if the called party  is connected to a CODEC/GW then it
> uses MEGACO protocol to create a session get the SDP info & passes it on to
> the calling Side.
>
> Rgds,
> DBS
>
>
> On Mon, Jul 13, 2009 at 9:43 PM, Mike Jiang <mike.jiang at andersontaylor.com>
> wrote:
>>
>>  Hi, All
>>
>>       I have a quick question: when I make a call from a SIP phone, the
>> SIP server sends 183 Session Process, 180 Ringing, and 200 OK msgs
>> sequentially back
>>
>>  to the phone. Usually at least one of three above has the SDP as the
>> body. The SDP contains the info about the IP, port, and audio codecs of the
>> target. My question is: is the IP/port that of the SIP Server or the
>> callee’s phone? The reason why I ask this is: the SIP phone only talks with
>> the SIP server directly, then the SIP server manages to relay voice packets
>> to the callee. As for how the SIP server routes the call to the callee,
>> that’s not the business the SIP phone cares.  So I think the IP/Port in SDP
>> is that of the SIP server rather than the callee’s phone. The SIP server
>> provider told me it’s the callee’s. I got confused.
>>
>>
>>
>>       Thanks for any input,
>>
>>
>>
>>       Mike J.
>>
>>
>>
>>
>>
>> __________ Information from ESET NOD32 Antivirus, version of virus
>> signature database 3832 (20090206) __________
>>
>> The message was checked by ESET NOD32 Antivirus.
>>
>> http://www.eset.com
>>
>> _______________________________________________
>> This is the SIP Forum discussion mailing list
>> TO UNSUBSCRIBE, or edit your delivery options, please visit
>> http://sipforum.org/mailman/listinfo/discussion
>> Post to the list at discussion at sipforum.org
>>
>
>
> _______________________________________________
> This is the SIP Forum discussion mailing list
> TO UNSUBSCRIBE, or edit your delivery options, please visit
> http://sipforum.org/mailman/listinfo/discussion
> Post to the list at discussion at sipforum.org
>
>