I've setup 2 UC500 with site to site vpn over the internet. Can I configure an ISDN backup for the crypto tunnel ? If yes, can I find a sample config ?
The Multi-site feature links a maximum of five small offices with IPSEC VPN connections to a Cisco UC500, one at each site, which is connected in full-mesh topology. PBX functionality is configured on each Cisco UC500 with a coordinated dial plan.