When planning your Wide Area Network, resiliency or backup options are something to consider. Depending on the resultant impact that a network failure might cause, your options are different. As well, your budget will affect your decision on this subject.
1. Backup via internet VPN is one cost effective option, depending on your company size and resultant manageability.
2. Single Router and access line, with ISDN dial-up, will provide redundancy should the local loop or any portion of the access connection other then the customer router fail. This also provided automatic re-routing, a more robust (and expensive) solution.
3. Dual Router with single or dual Access Lines, protects you if a router failure occurs. With a second access line providing an additional degree of protection. Dual diversity is important, to require that the loop follow a different pole path to a different central office.
4. Microwave internet VPN: this surprisingly affordable service is great in areas where it is offered since it eliminates the local loop issue.
5. Cellular Access Points: another redundancy option that eliminates the physical risk of the local loop. This option obviously requires that cellular data access be available at the specified location.
