Case Study: Dial Backup with Two Routers

Dial backup using a single router at the remote site still leaves a single point of failure—the router at the remote site. The obvious solution is to install two routers at the remote site, as illustrated in Figure 3-18.

Figure 3-18. Dial Backup with Two Routers

There are two problems with this solution; the first is that hosts on the 172.16.9.0/24 network must set their default gateways to either Router B's or Router D's Ethernet IP address to reach the rest of the network. No matter which one is used, if that router fails completely, all connectivity to this segment will effectively be lost.

The second ...

Get Advanced IP Network Design (CCIE Professional Development) now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.