On 3/25/13 7:21 PM, Brett Tate wrote:
> Hi,
>
> The following RFC 3311 snippets indicate why re-INVITE is recommended instead
> of UPDATE. Some of the common UPDATE failures are 504, 491, 481, 488, and
> 500 (with Retry-After); see RFC 3311 for more details. You may also be
> interested in RFC 6141, RFC 6337, and RFC 3264.
>
> "Although UPDATE can be used on confirmed dialogs, it is
> RECOMMENDED that a re-INVITE be used instead. This is
> because an UPDATE needs to be answered immediately, ruling
> out the possibility of user approval."
>
> "If the UAS cannot change the session parameters without prompting
> the user, it SHOULD reject the request with a 504 response."
While this is true for the general case, the original question was about
HOLD. You don't expect any user interaction for hold, and failure to go
on hold isn't a big deal.
Also, presumably you wouldn't use UPDATE unless the other end has
already signaled support for UPDATE, so failure there is also unlikely.
So I don't see much problem with using UPDATE given those constraints.
OTOH, an implementer is likely to want to minimize the number of
different code paths that must be implemented. You likely must implement
use of reINVITE for those cases where the other end does *not* support
UPDATE. And if so, why not use it in all cases.
So in practice I would think using UPDATE here would only make sense in
an environment where all your calls are known to involve a peer that
supports UPDATE.
Thanks,
Paul
>> -----Original Message-----
>> From: [email protected] [mailto:sip-
>> [email protected]] On Behalf Of Tarun2 Gupta
>> Sent: Monday, March 25, 2013 12:41 AM
>> To: Tamjid Ali; Sip-implementors
>> Subject: Re: [Sip-implementors] UPDATE instead of re-INVITE
>>
>> Hi
>>
>> 1 thing that I can think of is that the UAS might not support Update
>> (the UAS can indicate its support of Update through an Allow header in
>> 200 OK of Invite)
>>
>> Regards
>> Tarun Gupta
>> Aricent
>>
>> -----Original Message-----
>> From: [email protected] [mailto:sip-
>> [email protected]] On Behalf Of Tamjid Ali
>> Sent: Saturday, March 23, 2013 11:11 PM
>> To: Sip-implementors
>> Subject: [Sip-implementors] UPDATE instead of re-INVITE
>>
>> Hi All,
>> Can anyone please explain if we are using UPDATE instead of re-INVITE
>> for call hold what are the problem may occurred?
>> thanks to all in advance.
>
>
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