Re: [Sip] Need opinion

["Kevin P. Fleming" <[e-mail]>]

On 09/30/2010 10:46 AM, Worley, Dale R (Dale) wrote:
> ________________________________________
> From: [e-mail] [[e-mail]] On Behalf Of [e-mail] [[e-mail]]
> 
> I am some doubt regarding the RFC4566.
> 
> If you see the red marked attribute this same attribute is getting repeated in the SDP.
> I just want to confirm, is this  acceptable behavior?
> ________________________________________
> 
> According to the principle of "Be strict in what you send and lenient in what you accept", sending two lines that say "a=rtpmap:98 AMR/8000/1" should not be done, but the receiver should accept them and interpret them to mean that payload type number 98 is "AMR/8000/1".

To add to what Dale said... if the sender had sent two "a=rtpmap:98"
lines that did not have the same contents, the behavior of the receiver
is undefined, as the sender is not RFC compliant. The receiver could
choose to accept the first one, the second one, or neither, or even
reject the entire request.

This does not mean, though, that the receiver is obligated to watch for
duplicated "a=rtpmap" lines and verify that they match. It *can* do so,
but it can also treat the second one the same as it would if the
contents did not match the first one. As Dale said, though, it's not
costly to confirm that the second one does in fact match the first one,
and accepting the duplicate line is not harmful.

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
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