[asterisk-dev] decrease Max-Forwards header

[Johansson Olle E]

17 sep 2008 kl. 16.06 skrev Raj Jain:

> On Wed, Sep 17, 2008 at 9:50 AM, Benny Amorsen <benny+usenet at amorsen.dk 
> > wrote:
>> "Raj Jain" <rj2807 at gmail.com> writes:
>>
>>> IMHO, this makes some sense but not a whole lot because in the
>>> scenario you mentioned Asterisk is acting as a B2BUA not a proxy. It
>>> is a proxy's job to detect loops and not B2BUA's.
>>
>> This is true, but it is rather easy to make a loop with Asterisk. If
>> we could use a piece of proxy technology to mitigate that problem,
>> then I am all for it. As long as it doesn't break anything, of  
>> course.
>>
>> It wouldn't solve everything; I have made call loops on PRI circuits
>> several times, and Max-Forwards couldn't do anything about that.
>> Still, better than nothing.
>
> Fine. I guess this can be viewed as a "policy" implemented in the
> B2BUA, where the Max-Forwards is decremented as a call traverses
> through the B2BUA. That way, we are not breaking any rules of the
> protocol. As long as this is not Asterisk's default behavior, I guess
> it makes practical sense to implement this.
>
Well, Max-Forwards is by default only decremented in a proxy,
UA's should not bother with it at all.

To clarify: We would not decrement it, but we would start the new
call on the other side with a Max-Forwards setting that is lower
than the incoming call. That makes sense. Right now we're
resetting it, regardless of value.

This has to be configurable.

/O