Subject: [SIP] Questions on Figure 11 of RFC2543bis

From: "Ajay Chitturi" <[email-masked]>
Date: Mon, 19 Jun 2000 19:41:21 -0700

In this diagram does "give up" mean the caller gave up and hung 
up the call or that the state machine gave up ?

Since there is another arrow from the "Calling" state showing 
"7 INVITE sent", I assume the arrow to the right of "Calling" state 
happens when the user hangs up. In this case shouldn't the state machine
wait for the response to INVITE and send an ACK ?

The arrow to the right of "Call Proceeding" state could happen if either
the caller hangs up or the state machine hangs up. Is the timeout for
when 
the state machine will give up in this state specified in the draft or
left 
to the implementation. If the user hangs up, shouldn't the state machine
wait for the response to INVITE and send an ACK ?

Also section 4.2.4 states :
   A BYE request from either called or calling party terminates any 
   pending INVITE, but the INVITE request transaction MUST be completed 
   with a final response. 

Does this mean that the ACK also needs to be sent after getting 
the response ? 

Thanks
Ajay.

---

From: Jonathan Rosenberg <[email-masked]>
Date: Thu, 22 Jun 2000 17:29:12 -0400

> Ajay Chitturi wrote:

I believe it means that the caller gives up.

> wait for the response to INVITE and send an ACK ?

I believe it should. This is reflected in the server state machine on
the pages following. In fact, hanging up has no effect on the
transaction at all (its termination should be sped up, since the far
side will send a final response to the INVITE).

> wait for the response to INVITE and send an ACK ?

I don't think you can usefully distinguish between the "state machine"
giving up, and the user giving up. In any case, yes, you should wait for
the response and send the ACK. Of course, from a UI perspective, the
call is hung up and that should be reflected; the transaction kind of
hangs around (much like TCP state for closed connections) to clean up.

> Does this mean that the ACK also needs to be sent after getting

Once again, yes.

Transactions are independent entities that should always complete by
themselves.

-Jonathan R.

-- 
Jonathan D. Rosenberg                       72 Eagle Rock Ave.
Chief Scientist                             First Floor
dynamicsoft                                 East Hanover, NJ 07936
[email-masked]                     FAX:   (973) 952-5050
http://www.cs.columbia.edu/~jdrosen         PHONE: (732) 741-7244
http://www.dynamicsoft.com

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