Re: [MMUSIC] draft-ietf-mmusic-sctp-sdp-07 SCTP SDP syntax question

Paul Kyzivat <pkyzivat@alum.mit.edu> Wed, 01 October 2014 14:05 UTC

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Subject: Re: [MMUSIC] draft-ietf-mmusic-sctp-sdp-07 SCTP SDP syntax question
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On 9/30/14 8:12 AM, Christian Groves wrote:

> 2) Cl. 4.1.1 sctp-port: The syntax for sctp-port indicates the dual use
> of "=", i.e.
>
> sctp-port-attr = "a=sctp-port=" portnumber
> port-number = port
>
> That doesn't appear to be consistent with the example in clause 4 which
> has:
> a=sctp-port 4060
>
> To match that the syntax needs to be updated, something like:
>
> sctp-port-attr = "a=sctp-port" SP portnumber
> port-number = port
> I'm not sure why "portnumber" is used when "port" is commonly used in
> clause 4.1?
>
> The syntax could be simplified to:
> sctp-port-attr = "a=sctp-port" SP port

The above is not a valid syntax for an SDP attribute. The value of an 
attribute must be separated from the name by a ":".

Please take a look at draft-ietf-mmusic-rfc4566bis-12 for more on this.

That includes my proposal for cleaning up how attributes are defined. I 
suggest using that style in this draft.

In a similar vein, I suggest that when defining the new fmtp usage, just 
provide the new syntax for format-specific-params, not for the whole 
attribute.

(While writing this I'm realizing that the new text defining the fmtp 
parameter in 4566bis should specify *how* this should be done.)

	Thanks,
	Paul