Reinforcing WiFi Redundancy

Redundancy is routine in the constant scramble to keep a conventional enterprise network functioning. But the wireless infrastructure is often ignored, leaving enterprises vulnerable to malicious attacks and network failure.

No longer a hot-spot sideshow, wireless is on track to become the primary enterprise network sooner than you might think. "Although the all-wireless enterprise, such as Intel's, is not yet the norm, it is expected to be by mid- to late-2008 and into early 2009," says Chris Silva, an analyst with the Forrester research group based in Cambridge, Mass. Redundancy neglect now will only cause greater problems in the future.

Wired + Wireless = One Network
The impending move from wired to wireless is prodding IT professionals to shift gears and build a bulwark of safeguards. Successful transition, however, requires more than simply duplicating key parts of wireless hardware. "A redundant infrastructure means anticipating points of failure for the network and creating ways of preventing the network from failing, no matter what nightmare scenario takes place," advises Stan Schatt, VP of ABI Research in New York, N.Y.

Among the points of potential failures are the hidden recesses of the physical plant. "Redundancy efforts must ensure 100 percent coverage of the building as much as it must ensure constant reliability of the network. You have to account for new obstacles such as building materials, walls, stairwells and corner dead zones," advises Silva.

Paradoxically, despite intensified scrutiny of the wireless infrastructure, IT departments cannot afford to ignore the wired network. (article continues)


"Even though these networks are separate, wireless users often connect to a wire-line network. A network manager has to be aware of issues associated with the WiFi device and network that could bring down the wire-line network," observes Schatt.

In short, the entire network system -- both wired and wireless -- is mission critical.  Yet too many enterprises are missing the message, warns San Jose, Calif. -based Rachna Ahlawat, research director of Gartner's Wireless Networking. "There's not much difference in redundancy for wired and wireless. Both must be covered."

Eight Secrets to Achieving Redundancy
How can IT departments super-size their redundancy plans? Consider these eight ways to reinforce your entire network:

  • Intelligent switches (controller) As the wireless LAN (WLAN) industry moves toward a model with the real intelligence centered in the switch or controller, a resilient WiFi network should have additional unused switches to permit active failover. 
  • Battery backup for the switch In the event of a power failure, backup power is needed for the switch and for access points that rely on power over Ethernet (POE).
  • Hot-swappable spares for the switch Most switches now permit hot-swapping of failed circuit boards, allowing quick replacement of components without the need to shut down the entire network segment.
  • Dense access point configuration Today's access points can direct their traffic to replacements if one fails, but if the access points are out of radio range for users, they are useless. Make sure there are sufficient access points for the system. (article continues)


  • Load balancing Increasing use of voice-over-wireless LAN (VOWLAN) is pushing demand for an industry standard for load balancing. Until voice-over WiFi calls can be recognized and equally distributed among access points, a user could get a busy signal when trying to make a call. To avoid this unacceptable condition, IT departments may need to design their own load balancing solutions.
  • Roaming Users need to be able to roam between subnets without having their connections dropped. The IEEE 802.11r standard that supports this function has not yet been ratified, but most equipment vendors are offering their own proprietary solutions in the interim and promise to upgrade to the final standard when it is approved.
  • Battery-saving features To avoid dropped network connections if a handheld WiFi device, such as a scanner or a WiFi phone runs out of battery power, most equipment manufacturers offer some version of WMM battery saving.
  • Intrusion detection and prevention Network managers must design their WiFi networks to have adequate sensors to identify hackers and knock them off before they bring down the WiFi network.

Make sure your enterprise is prepared for the future surge to an all-wireless network. The steps toward achieving wireless redundancy may differ from normal redundancy efforts, but the end goal remains the same. "Most network managers are looking for network resiliency; that means creating a network that is resilient enough not to fail should a component fail or should a hacker attack the network," says Schatt.