[Freeswitch-dev] call forward howto

kokoska rokoska kokoska.rokoska at post.cz
Mon Apr 7 08:27:53 EDT 2008

Michael Jerris napsal(a):
> On Apr 7, 2008, at 3:45 AM, kokoska rokoska wrote:
>>> We already kill the call if the Max-Forwards makes it to zero.
>> No, unfotunately, Max-Forwards is not for the same thing.
>> X-HopCounter we (I and lot of VoIP providers around me) use for  
>> overall
>> "hops" (visited call-routers) counting - ISUP and SIP.
>> This variable comes from SS7 world (ISUP) and is mandatory for good
>> interconnection (helps against loops etc. - similary as MaxForwards
>> does) especialy if RNPDB comes into the game :-)
>> First router sets HopCounter to 31, every next router should decrement
>> the value on every single processing attempt (i.e. if call goes thru 5
>> extensions in Freeswitch dialplan it should be decremented by 5) and  
>> on
>> 0 or lower values router should stop routing and reject the call...
> I think we would probably convert this to a Max-Forwards when doing a  
> sip interconnect, I need to see if we decrement it in a transfer  
> within the switch, I believe we already do.  But like all the other  
> headers, we can get it with variables, and create the other header,  
> but we only auto decrement the Max-Forwards.  That being said, it is  
> not required that we start Max-Forwards at 70.  I have in the past  
> passed this along from ss7 by either passing the value directly from  
> ss7 or using a ratio calculation similar to how cisco does it.
> Mike

Thank you very much, Michael, for your comment!

Converting HopCounter to Max-Forwards may do the job, but I still need 
to append special header X-HopCounter, because operators look for it.
But i can simply "copy" content of Max-Forwards or do the math by myself :-)



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