Hi Nitin,
Please find the explanation below which states that the increament is always
done by 1 as per RFC.
RFC 4566:
5.2.
Origin ("o=")
o=<username>
<sess-id> <sess-version> <nettype> <addrtype>
<unicast-address>
<sess-version> is a version number for this
session description. Its usage is up to the creating tool, so long
as <sess-version> is
increased when a modification is made to the
session data. Again, it is RECOMMENDED that an NTP format timestamp
is used.
According to another spec RFC 3264, this incrementing of version
implies new offer:
RFC 3264:
When
issuing an offer that modifies the session, the
"o=" line of the new SDP MUST be identical to that in
the previous SDP, except that the version in the origin field
MUST
increment by one from the previous SDP. If the version in the
origin line does not increment, the SDP MUST be identical to the SDP
with that version number.
Regards
Sampat
On Tuesday, 15 July 2014 4:36 AM, NK <[email protected]> wrote:
Hi Paul,
Thanks!!. Yes i checked 3264 and it says it should be increment by 1.
However i am more concerned that if there is re invite and in 200 OK SDP(in
the correspondence of re-invite) there is no change as compare to previous
SDP then also <session-version> should increment by 1?
Regards,
Nitin Kapoor
On Mon, Jul 14, 2014 at 7:02 PM, Paul Kyzivat <[email protected]> wrote:
> On 7/14/14 6:14 PM, NK wrote:
>
>> Dear All,
>>
>> I have query regarding the Session version in SDP. I know if we are making
>> any changes in SDP then from 183 to 200OK with SDP then there will be
>> increment in session version from 183 <session version = 1> to 200 OK
>> <session-version=2>. However i have 2 doubt as below. Can you please help
>> me on this.
>>
>> 1) Is that Value should be increment by 1 only? I mean suppose in 183
>> w/SDP we have Session Version =1 , then is that mandatory that we should
>> have "session-version=2" or it can be 3 directly. OR
>>
>> 2) if in 183 w/SDP and 200 Ok we had the same value but when "re-invite
>> happened then SDP was same but "session-version" value incremented from 1
>> ==>3 directly. I feel it should be 2 (i mean increment by 1 only). Please
>> advise if my understanding is correct.
>>
>
> RFC 3264 requires that it be incremented by 1. But if you are on the
> receiving side I suggest you be lenient about this.
>
> Thanks,
> Paul
>
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