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problem.

But i have doubt it solves the problem in all scenarios.

The list of dialed interfaces has two purposes:
1. Avoid calling the same interface twice within the same call 
(imagine huge dialplan logic involving local channels, call forwards from
a database and stuff: with call waiting (=on) you could end up ringing the
same device multiple times within the same call)
2. Avoid the forwarding loop which goes round and round when two
extensions setup a static forward (SIP 302) in the device / SIP UA
directly. 
(as described above)

We have a few different scenarios to keep in mind, hopefully i didn't
oversee something:

1. user answers (directly or via pickup) call and then transfers the
caller either attended or unattended
(should clear the list of dialed interfaces, fixed with your patch)
2. user has a static forward set up as described above 
(i.e. via call forward menu, executed as SIP 302 on snom)
(here the list of dialed interfaces is important to avoid endless
looping)
3. user does NOT answer but forwards the call manually 
(i.e. via transfer button, executed as SIP 302 on snom)

Note that scenario 2 and 3 are not (easily) distinguishable from each
other.
In scenario 2 we really want to avoid looping.
In scenario 3 this is not optimal, imagine two users in the same room. 
A forwards to B, then says "please send the call back to me".
(-> call drops)

I assume with your patch, the scenario 3 will not work, so a user that
manually forwarded a call cannot receive it again.

Locally, we have a patch in place (for testing) that removes a specific
interface from the list of dialed interfaces when two conditions are true:
1. interface is already in ringing state -> shows that device doesnt
directly forward and could receive the call.
2. call forward is set up.

This works pretty well here, all above scenarios work fine. 
Pity is, the patch is against a 1.4.30 which already has several custom
modifications applied and i didn't have time yet, to write and test this
again with a vanilla 1.4.33.

Also look at cmaj's comment above. He says all of these scenarios work
fine with 1.8.2-rc. Again, didn't find time yet to confirm that it works
well in 1.8.2. 

Issue History 
Date Modified    Username       Field                    Change               
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2011-01-14 04:51 kaii           Note Added: 0130488                          
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