-----Original Message----- From: Juha Heinanen [mailto:jh@tutpro.com] Sent: Tuesday, December 21, 2004 9:25 PM To: Richard Cc: serusers@lists.iptel.org Subject: [Serusers] call log and accounting for forwarded and referred calls

Richard writes:

...

When a SIP call is blind-transferred with REFER and forwarded with "302 moved temporarily", UA would start a brand new call. The problem is how

to

...

log and account for their calls. For example, A calls B, B sends 302

and

...

uses C's number as contact. The new call is made from A to C. The call

log

...

would show it is from A to C. The call log should at least have an indication of B forwarding the call. Also B is supposed to pay the

bill.

It

...

is not A although the call log shows it is A to C. A has no knowledge

that a

...

toll call is made when calling B.

richard,

i disagree that in case of 302, b should pay the bill. 302 means "b has moved to c and it is up to you if you want to try this new uri".

if you want b to pay the bill, then b should configure ser to FORWARD the call to c, not to REDIRECT a to c.

The issue is that A has no choice to be forwarded or not. When a 302 is received by A, there is no option for A to continue or reject the call. In this example, B (an IP phone) sets his phone forwarding to C which is a long distance number. A is from PSTN. When A makes a call to B, B sends 302 to the PSTN gateway. The gateway forwards the call to ser which routes it back to C via the PSTN gatway. So in ser's call log, I see a call from A to C. Apparently I can't charge A or C. Only B is in my domain. But B is not even in the second call log. In my understanding, if B sets the forward setting on his phone to a toll number, he should be the one paying the bill.

This also applies even if A is in my domain.

Cheers, Richard

Atle Samuelsen writes:

At the moment SER does'nt do recursion on 302. If ser had done this, The world would be a bether place for all us.

it can be made to recurse on 302. in fact, i once patched ser to do so by turning 302 into a new invite. but then i started to think that the called user MUST have the choice of not paying for the forwarding and 302 is meant for that very purpose. if the user wishes to pay, then (as i said earlier) you instructs ser to FORWARD the call. if the called user does not want to pay, but wants to give the caller the choice, the user replies with 302.

so both options are and should be possible. talk to your SIP UA vendors if they don't properly support 302.

-- juha

...

In this example, B (an IP phone) sets his phone forwarding to C which is a

long

...

distance number. A is from PSTN. When A makes a call to B, B sends 302

to

...

the PSTN gateway. The gateway forwards the call to ser which routes it

back

...

to C via the PSTN gatway. So in ser's call log, I see a call from A to

C.

...

Apparently I can't charge A or C. Only B is in my domain. But B is not

even

...

in the second call log. In my understanding, if B sets the forward

setting

...

on his phone to a toll number, he should be the one paying the bill.

regarding pstn gws, i recommend that you turn off 302 processing, since otherwise your gw may end up paying for the forwarded (expensive) leg of the call, since, as you say, you cannot charge the PSTN caller.

Since logging and accounting is a problem, I want to only allow local numbers in the forward field. Is there any function available to match and modify the contact field. For example, if it is "Contact: sip:18085551212@mydomain.com", I should change it to "Contact: vm+(original-callee-number)@mydomain.com" which goes to voicemail. Are search() and append_urihf() good for this?

I think the same issue applies to REFER. However I won't be able to disallow a toll call on REFER. It is possible a secretary makes a toll call, then REFREs to the boss. So I have to find some way to log and account this.

Thanks, Richard