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Re: [MMUSIC] Progressing draft-garcia-mmusic-sdp-cs-01



The problem with using "-" for the port number is that it isn't allowed by the syntax of SDP. From 4566:

   media-descriptions =  *( media-field
                         information-field
                         *connection-field
                         bandwidth-fields
                         key-field
                         attribute-fields )

   media-field =         %x6d "=" media SP port ["/" integer]
                         SP proto 1*(SP fmt) CRLF

   port =                1*DIGIT

So unless you want to ammend 4566 you can't use "-" in the port field.

While 9 doesn't mean "not applicable", it is still a good choice in a case where the port number is irrelevant, because it doesn't conflict with any "real" port. This is the same logic that led to it being used in comedia.

	Thanks,
	Paul

Miguel A. Garcia wrote:
Take a look at the IANA registry of port numbers, port number 9:

discard           9/tcp    Discard
discard           9/udp    Discard
#                          Jon Postel <postel&isi.edu>
discard           9/sctp   Discard


Discard does not mean "not applicable" in my opinion.

/Miguel

Christer Holmberg wrote:
Well, I would say that port 9 means "do not care about this port" :) But, I guess it is a matter of taste.
Im my understanding, port 9 means port 9, as transport protocol port number 0x0009. In the one particular case of COMEDIA, _if_ the setup is _passive_, then the port number is ignored, and value 9 is used as a syntactical placeholder.

No?

If you say so :) I guess you're right.

Regards,

Christer
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The problem with using "-" for the port number is that it isn't allowed by the syntax of SDP. From 4566:

   media-descriptions =  *( media-field
                         information-field
                         *connection-field
                         bandwidth-fields
                         key-field
                         attribute-fields )

   media-field =         %x6d "=" media SP port ["/" integer]
                         SP proto 1*(SP fmt) CRLF

   port =                1*DIGIT

So unless you want to ammend 4566 you can't use "-" in the port field.

While 9 doesn't mean "not applicable", it is still a good choice in a case where the port number is irrelevant, because it doesn't conflict with any "real" port. This is the same logic that led to it being used in comedia.

	Thanks,
	Paul

Miguel A. Garcia wrote:
Take a look at the IANA registry of port numbers, port number 9:

discard           9/tcp    Discard
discard           9/udp    Discard
#                          Jon Postel <postel&isi.edu>
discard           9/sctp   Discard


Discard does not mean "not applicable" in my opinion.

/Miguel

Christer Holmberg wrote:
Well, I would say that port 9 means "do not care about this port" :) But, I guess it is a matter of taste.
Im my understanding, port 9 means port 9, as transport protocol port number 0x0009. In the one particular case of COMEDIA, _if_ the setup is _passive_, then the port number is ignored, and value 9 is used as a syntactical placeholder.

No?

If you say so :) I guess you're right.

Regards,

Christer
_______________________________________________
mmusic mailing list
mmusic at ietf.org
https://www.ietf.org/mailman/listinfo/mmusic


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mmusic mailing list
mmusic at ietf.org
https://www.ietf.org/mailman/listinfo/mmusic