Stacking M32x & line fail over to second PBX

[jloeken]

HI
NOW another hairy question.... "Stacking PBX"
if i have a 1800 number coming in over SIP into the first M32x and it has reached capacity, How do i share the load to the next M32x in the stack?

Assuming the capacity is sip 64 calls on the QuadroM32x.

Thanks

[hrant]

If the capacity limit is reached then Quadro rejects the inbound call sending appropriate SIP message back to SIP server. Regular stacking will not help in this situation. The simplest solution is to register the same 1800 number/account from two or many Quadros on the same ITSP. Hopefully your ITSP will allow that and when making the call to 1800 number, send the INVITE to all Quadros registered with the same 1800 number. As soon as the first Quadro accepts the call (it should be the Quadro which doesnt hit the limit), the SIP server will cancel all other invites. You can consider this method as some kind of stacking but actually it is SIP forking capability of SIP server.

[jloeken]

hi
so SIP forking? has anyone done it with engin and a quadro unit?
Is it the correct way to do things?

My theory on haw to achieve this correctly would be to register another engin (sip) account on the second Quadro, then with the first engin account or 1800 provider set up a busy call divert to the second number.
This would only work if the quadro sent a busy signal when it reached it's maximum sip capacity.??? Is this correct?

Thank You