[sr-dev] SIP-I ?

Javi Gallart jgallart at systemonenoc.com
Fri Mar 22 16:17:18 CET 2013


Hi

this is really a common practice among carriers. Actually the SS7 case 
is easier because, unlike in SIP with the To, From..., in a regular ISUP 
call the details of the initiating call are not sent in the backwards 
direction: an ANM message indicating the call was answered doesn't carry 
the numbers in the IAM that initiates the call. So it's a matter of 
billing properly and accurately.

Javi
On 03/22/2013 03:27 PM, Alex Balashov wrote:
> Yes, but what happens when those modifications, or responses based on those modifications, are returned to the sender? Much as with most SIP headers, the sending SS7 gateway can well say, "I didn't send that."
>
>
> Javi Gallart <jgallart at systemonenoc.com> wrote:
>
>> Thanks Alex
>>
>> the first thing that came to my mind is performing some number
>> manipulation. Imagine kamailio acting as a router for several carriers.
>>
>> One of them demands an international NOA with a weird prefix, whereas
>> the other one, for the same destination, requires a pound (#) at the
>> end, and so on. I agree with you in disliking idea of being too
>> "invasive" in the body of the sip message, but it's something already
>> doable for instance with SDP.
>>
>> Javi
>> On 03/22/2013 02:50 PM, Alex Balashov wrote:
>>> Hi Javi,
>>>
>>> The first question to ask is: if Kamailio could understand ISUP
>>> parameters, what would it do with them?
>>>
>>> If the answer is "not a whole lot", chances are it is something that
>>> only needs to be understood by the endpoints, and which Kamailio
>> would
>>> continue to be agnostic to, as it is now.  Kamailio is, above all
>>> else, a message relay.
>>>
>>> -- Alex
>>>
>>>
>>
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