[SIPForum-discussion] whats special in 202 Accepted

[Robert Sparks]

Folks are right here describing the intended difference between 202  
and 200.

200, in the abstract, says a mix of things about the transaction and  
perhaps some concept like a subscription or call above the transaction  
- it says "success"
202, again in the abstract, says the transaction succeeded, some mix  
of things above the transaction may have succeeded, but there's still  
some piece of work to do before "success" can be declared and that  
message will come through some other path.

That said, those abstractions have not been particularly useful in  
practice, and if I had a time machine, I would go back and argue 202  
out of the specs.

We ended up there while we were developing SIP Events and thought the  
client needed to learn from the SUBSCRIBE response whether its  
subscription was authenticated. By the time the engineering settled  
down and 3265 was produced, all of that data moved to the initial  
notify (in the Subscription-State
header field), leaving the 202 with no substantive meaning that was  
different than 200.

Effectively, there's no reason for an implementation to treat a  
received 200 and 202 as different. They should cause exactly the same  
things to happen.
To maximize interop, an implementation should always _send_ exactly  
what the specs say to send, but you should accept either response as  
meaning
the same thing.

RjS

On Dec 16, 2008, at 2:47 AM, Andro wrote:

> Hello Mark.
>
> I understand the difference. But if the server has not processed it  
> yet, why does it sometimes return 488 Not Acceptable Here to a REFER  
> request?
> I think that the server processes the request and check its  
> validity, but the request (e.g. a call transfer) has not been  
> completed yet. this can be the difference.
>
> Do you agree?
>
> Andrea
>
> 2008/12/15 Mark Holloway <mh at markholloway.com>
> 200 OK equates to a successful completion of a request by a SIP  
> server.  202 Accepted means the server has received the request but  
> has not processed it yet.
>
>
>
> From: discussion-bounces at sipforum.org [mailto:discussion-bounces at sipforum.org 
> ] On Behalf Of Ayyanar PK
> Sent: Sunday, December 14, 2008 6:50 AM
> To: discussion
> Subject: [SIPForum-discussion] whats special in 202 Accepted
>
>
> Hi Everybody,
>
> I want to know why REFER is always accompanied by 202 Accepted, why  
> not 200 OK. what is special in 202 Accepted message. Please explain.  
> I went thro the RFC but didn't get a good explanation.
>
> Regards,
> Ayyanar
>
>
> Dear discussion ! Get Yourself a cool, short @in.com Email ID now!
>
>
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