Re: [MMUSIC] I-D Action: draft-ietf-mmusic-sdp-miscellaneous-caps-04.txt

On 3/15/13 2:11 AM, Hadriel Kaplan wrote:
> Sorry, I didn't notice there was a lengthy email chain about this topic.  Ignore my email below.  It appears from the later emails that others were also confused by the wording of that section, but they know what they meant it to say.
>
> Although I still have one simple question: when is it ok to use a 'ccap' attribute containing either an IP4 or IP6 address?
Based on the thread, that seems to be a discussion that needs to happen.

> For example, how is this useful:
>
>      m=audio 9 PSTN -
>      c=PSTN E164 +15555556666
>      a=ccap:1 IN IP4 198.51.100.7
>      a=tcap:2 RTP/AVP
>      a=omcap:1 0
>
> Since there is no port number being offered for the IPv4 ccap, and the number 9 is being used for PSTN, how would this actually work??
It wouldn't; you could only do it in the other direction (i.e. start 
with "IN" and then offer "PSTN" as an alternative configuration) - not a 
terribly generic connection data capability.

-- Flemming

> -hadriel
>
>
> On Mar 15, 2013, at 1:38 AM, Hadriel Kaplan <HKaplan@acmepacket.com>
>   wrote:
>
>> For section 3.1.2, page 9:
>>   The 'ccap' attribute MUST NOT be used in
>>   situations where an existing mechanism (such as Interactive
>>   Connectivity Establishment (ICE) [RFC5245]) can be used to select
>>   between different connection addresses (e.g.  "IP4" and "IP6" or
>>   different IP addresses within the same IP address family).
>>
>> What does that sentence actually mean??  What's a "situation" where an existing mechanism *can* be used?
>>
>> Does it mean 'ccap' MUST NOT be used if ICE is also used - i.e., they cannot both be in an offer?
>> Does it mean 'ccap' MUST NOT be used if it's technically possible to accomplish using ICE, even if the device in question doesn't support ICE?
>>
>> When is it ok to use a ccap containing an IP4 or IP6 address?
>>
>> -hadriel
>>
>>
>> On Mar 13, 2013, at 11:08 AM, Simo.Veikkolainen@nokia.com wrote:
>>
>>> Hello,
>>>
>>> We just submitted a new version of the miscellaneous-caps draft, with text that states that if the connection data capability attribute (a=ccap) is used the port number in the resulting SDP MUST be the same as in the original "m=" line, except for PSTN type bearers (when the port number used is 9).
>>>
>>> Regards,
>>> Simo
>>>
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