Dvir Oren ([EMAIL PROTECTED]):
> Are the tags in 'to' and 'from' plus the call-id sufficient to find a
> call-leg? It appears from the replaces draft that this is all is
> needed. However, at least in my implementation, I also need the 'to'
> and 'from' themselves, and not only the tags.
It's unclear to my why you feel so strongly about needing the full to
and from headers.
In almost all cases, the call-id alone should be sufficient to
identify an active call. For Replaces, the only cases I can think of
where the call-id might be insufficient are:
a) Two UAs answer the same call and both are accepted. When an INVITE
arrives with a replaces, there is a possibility that both UAs
receive the INVITE (some transparent proxy may have decided to fork
it). In this case, the UAs each check to see who's tags are
listed to determine if they should honour the Replaces.
b) Some broken UA makes many calls under the same call-id. In this
case, checking the tags is a cheap way of identifying which call
was intended.
Clearly in these cases, having the tags is useful, and having the full
to and from would be more 'correct' (but AFAICT not, as you claim,
required). My reason for just using the tags is a practical one: if
the full to and from are used, the escaping and unescaping gets much
worse for very little gain, and we've also greatly increased the length
of the header.
I worry about:
Replaces: [EMAIL PROTECTED];[EMAIL PROTECTED]%3bmobileid%3d9775
;to-tag=88f787f
from:
Refer-To: sip:[EMAIL PROTECTED]?
[EMAIL PROTECTED][EMAIL PROTECTED]
%253bmobileid%253d9775%3dto-tag%3d88f787f
Where double-escape code decoding is required.
--
Billy Biggs [EMAIL PROTECTED]
http://www.billybiggs.com/ [EMAIL PROTECTED]
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