[SR-Users] branches usage

[Carsten Bock]

Hi,

you need the "append_branch" only, if you modify the request URI in
your config (e.g. by doing a lookup()) and you want to have another
branch (e.g. parallel forking to voicebox).

Carsten

2012/3/28 Uri Shacked <ushacked at gmail.com>:
> OK...
> It worked great... and, no append_branch() was needed... only t_on_branch
> with the main branch route.
> When will i need to use the append_branch?
> BR,
> Uri
>
> On Wed, Mar 28, 2012 at 4:00 PM, Uri Shacked <ushacked at gmail.com> wrote:
>>
>> Hi,
>>
>> Thanks, this was very helpful for understanding.
>>
>> Still let’s see if i got it right:
>>
>> I get the INVITE.
>>
>> Do whatever I do on the main route.
>>
>> Then do:
>>
>> “append_branch();”
>>
>> “changes….changes…..;”
>>
>>  Now before the t_relay do t_on_branch(name of branch).
>>
>> Get the reply (301 in my case)
>>
>> And from here I am back to the original request?
>>
>> maybe a stupid question now but - I must use the append_branch()  right
>> :-)?
>>
>> BR,
>>
>> Uri
>>
>>
>>
>> Hi,
>>
>> On 03/27/2012 04:46 PM, Uri Shacked wrote:
>> > In my case i need to change the header and then send it.
>> >
>> > Here the case works if i make the changes after i sent the invite and
>> > got the reply. As i know the t_on_branch will work after the invite is
>> > sent... am i wrong?
>> >
>> > There are many questions to ask about the branches... when do they work
>> > > in a serial manner, when parallel... where can i find it documented best?
>>
>> Actually it's quite simple. If a request comes in and you modify it in a
>> normal route (e.g. calling rtpproxy_offer(), uac_replace_from(), adding
>> additional headers and stuff like that) and you send it out using e.g.
>> t_relay(), then in a serial scenario when you re-enter via a
>> failure-route, these changes will still be there (which is not always
>> what you want).
>>
>> On the other hand, if you register a branch route via t_on_branch() and
>> do your changes there instead of prior to calling t_relay(), then these
>> changes from branch route will be rolled back, and you can do your
>> changes easily again in the same or another branch route starting with
>> your original message. This is important for example in serial call
>> forward scenarios, where the first destination might require an
>> rtpproxy, but the second doesn't, or when the first destination requires
>> different custom headers compare to the second.
>>
>> Basically the same applies to parallel scenarios. If you modify your
>> message before calling lookup() and you've multiple contacts registered
>> for your destination, then your changes will apply for all branches
>> which are created by that. However if you move your modifications to a
>> branch route, then you can work on your messages individually, depending
>> on the branch.
>>
>> Hope this clarifies it a bit.
>>
>> Andreas
>>
>
>
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