Re: [MMUSIC] Connection Data Capability (ccap) and IP-addresses (draft-ietf-mmusic-sdp-miscellaneous-caps-04)

Hadriel Kaplan <> Sun, 24 March 2013 17:00 UTC

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Thread-Topic: [MMUSIC] Connection Data Capability (ccap) and IP-addresses (draft-ietf-mmusic-sdp-miscellaneous-caps-04)
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Subject: Re: [MMUSIC] Connection Data Capability (ccap) and IP-addresses (draft-ietf-mmusic-sdp-miscellaneous-caps-04)
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On Mar 20, 2013, at 5:56 AM, wrote:

> The ccap attribute should be able to carry either an IP or PSTN address; that way either a PSTN or an IP bearer could be offered as the highest priority configuration (in the "m=" line).  However, if we want to clarify the intended use of ccap, we could modify the first sentence to read:
> <quote>
>   The 'ccap' capability attribute is intended for offering
>   alternative connection addresses where the <nettype>
>   is "IN" or "PSTN", i.e. selecting between an IP based
>   bearer or a circuit-switched bearer.
> </quote>

That is not technically possible, in practice.  If a ccap were to contain an IN for an IP Address family, there is no port number indicated anywhere for that IP address.  Therefore it can't be used to indicate an IP Address alternate in practice, since one couldn't use the address alone.

So... either we re-introduce the port number so that a ccap can actually be used to indicate an IP Address, or we make ccap only usable for PSTN and not IN.