[Freeswitch-dev] call forward howto

Michael Jerris mike at jerris.com
Mon Apr 7 07:51:37 EDT 2008

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.


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