Need you all opinion..
Site A, site B, site C, site D is connected using leased line each other. We are using Cisco 1800, 2800 and 2900.
Each site also have Internet connection using ADSL connected to firewall, we are using pix 501 and ASA 5510.
My question is, can i use the existing ADSL line to be use as a backup line if the leased line is down on any of the site??
And i want it to trigger itself, once the leased line is down, the firewall UP the backup line? something like that..
Thats a quite common setup:
You build IPSec-Tunnels (best to use VTI in this case) between the routers through the ADSL and run a routing-protocol through your tunnels and your leased lines. Make the routing prefer the LL and if that connection breaks, it converges to the VPN.
No, all these routers come with onboard acceleration for IPSec. You only need a Security-Image (1800, 2800) or a security license (2900).
Btw: Your PIX 501 should be dumped as there is no support and no security-fixes any more.