With wide area network (WAN) or LAN disaster recovery, certain criteria must be identified and satisfied before choosing an approach.

For WANs, the key criteria for network recovery are:

• Physical diversity at the local and wide-area levels
• Availability of multiple service providers
• Scalable bandwidth that can adapt to emergency disaster recovery (DR) requirements in real time with no penalty fees

You should also develop an accurate map of the network to identify any single points of failure. If using WAN optimization software or an appliance, take advantage of the backup and recovery capabilities it may offer.

For LANs, the key network recovery criteria are:

• Network cabling with sufficient bandwidth
• Backup servers, switches, routers and hubs
• Backup power supplies
• Cable pathways that run vertically in the building risers and horizontally across the floors

For WANs, loss of or damage to in-building network connectivity devices will disrupt service. Loss of connectivity to the building from the carrier’s LAN (e.g., a cable cut) will also shut down the network. Carrier service outages in the WAN “cloud” may have far-reaching implications to your organization and many others.

For LANs, damage to servers, switches, routers, hubs and internal wiring will disrupt service. The best way to address a LAN outage is to have a detailed network map of all LAN components. This can be generated by a network scanning tool, which can be obtained from commercial and open source products. The baseline network map will help determine which devices should be in an inventory of spare LAN components, such as servers, switches, routers, hubs, and a supply of cable and connectors. Configuration details for every device on the LAN are essential for recovering a device.

Backups of configuration data, network maps and device inventories must be processed in advance so critical IT information can be accessed in a disaster. Documented network recovery plans with detailed procedures for recovering WAN and LAN assets are also important.