Re: [Sip] re: WGLC: resource priority (3)

[Rohan Mahy <[e-mail]>]

Ken,

Just because you normally don't send the value "off" doesn't mean it 
doesn't exist.

thx,
-r



On Friday, January 16, 2004, at 05:19  AM, Ken Carlberg wrote:

>> [MAP] You're going to have to explain how that could work, considering
>
>> that the draft states:
>>
>> Every namespace must have a default level.
>> The default is assumed in the absence of a priority level (in a
>> message).
>>
>> That means that, if there is only one priority value in the
>> namespace (such as "on") registered with IANA, it must be the
>> default, and any INVITE that does not contain an RP-header is
>> treated as if it contained the default value ("on").
>
> You've just explained your own request.
>
>> How would it be possible to signal the "off" value?
>
> "off" = absence of message/signal, ie, the SIP Invite msg is the same 
> as
> if the R-P header didn't exist.  If I'm forced to have an "off" R-P
> header value, than I'll need to write more code to recognize this, and
> I'll do more processing for the label and the subsequent 
> authentication.
> And what did I gain in doing this added work compared to not sending 
> the
> R-P header Invite?  Nothing.  I'm going to have a fun time explaining
> that to my guy who has written code to support the previous versions of
> the draft that he is going to write additional code that amounts to no
> gain.
>
> In fact, in thinking about this, it will be code that will never be 
> used
> in our client using a namespace to support the NS/EP codepoint.  The
> trigger for our SIP R-P client is a particular phone number sequence.
> Absence of that sequence means that all other calls from that client 
> are
> regular SIP messages.
>
>> I think the age old practice of being conservative in what you send
>> applies to what we say to each other, not what signaling is sent by
>> telecommunications devices :>}
>
> agreed on the former, but Postel applied it to the latter and drilled 
> it
> into many a head, who in turn continued the drilling :-). (note, the
> full quote is be liberal in what you accept, and conservative in what
> you send, see rfc-760)
>
>> Explain how one would signal the NS/EP codepoint case with only one
>> value (which is the default).
>
> You already have.  And I've added a case in point where the "off" value
> will never see light of day.
>
> As a side note, this issue has been discussed in the past on a 
> different
> list, so there is a reason why the draft has taken the position not
> requiring at least 2 values per namespace.  My desire is to defend the
> current position, but the issue is not critical, so I will not add any
> other comments on the matter on the list.
>
> Regards,
>
> -ken
>
> ps, it would be nice to see plain text messages rather than html marked
> ones.
>
>


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