Secondary public IPs in a BGP configuration

[rainingrose]

We have dual service entrances to our building, connecting to GigEth 0/2 and 0/3 (differing Public IPs on both) on our NetVanta3140.  We have BGP configured between those two connections so that traffic will auto re-route should one of the connection go down.  GigEth0/1 connects to our local LAN (Private IP).  I have a PBX on private side which has a specific secondary public IP configured on it needing to communicate with carrier SBX on public side.  This public IP on my PBX needs to be defined as a secondary Public IP within the NetVanta.  I can't define same secondary IP on both GigEth 0/2 and 0/3, how do I configure this so that PBX will communicate properly, no matter which service entrance happens to be the functioning circuit at the time?

[jayh]

If your two public IP blocks are from different ISPs and you do not have your own IP space advertised to both, then BGP won't help in this situation. ISP A won't route public space belonging to ISP B. You could try to see if your carrier can assign two public IP addresses to your PBX in a failover scenario. Or use a hostname for the PBX with SRV records.