An ounce of prevention could cure the health of your network

Insightful analysis by consultants Steve Taylor and Jim Metzler, plus links to the latest WAN news headlines

The proverbial "ounce of prevention" being worth a "pound of cure" extends beyond your own health to the health of your network as well. And one of the areas in which this ounce of prevention can be especially useful is routing.

It’s no secret that this has been an issue for as long as we’ve had “automatic rerouting.” Even back in the days of X.25 and T-1/E-1 multiplexer networks, re-optimization was an issue. For instance, imagine there's a break in a flaky link between two points. At some point, the network “decided” to take an alternate path between the two points. But, especially if the link was “automagically” restored somehow, then when did the network re-optimize and revert to the original path?

Contrary to some beliefs, the fact that IP has the destination address in every packet does not imply that a routing decision is made on a packet-by-packet basis. In fact, the contrary is true. Unless there is a stimulus for a switch/router to make a change to a routing table, the packets will continue to follow the same path.

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The proverbial "ounce of prevention" being worth a "pound of cure" extends beyond your own health to the health of your network as well. And one of the areas in which this ounce of prevention can be especially useful is routing.

It’s no secret that this has been an issue for as long as we’ve had “automatic rerouting.” Even back in the days of X.25 and T-1/E-1 multiplexer networks, re-optimization was an issue. For instance, imagine there's a break in a flaky link between two points. At some point, the network “decided” to take an alternate path between the two points. But, especially if the link was “automagically” restored somehow, then when did the network re-optimize and revert to the original path?

Contrary to some beliefs, the fact that IP has the destination address in every packet does not imply that a routing decision is made on a packet-by-packet basis. In fact, the contrary is true. Unless there is a stimulus for a switch/router to make a change to a routing table, the packets will continue to follow the same path.

As pointed out in a recent paper by Packet Design, titled “Proactive Routing Health Audits with Route Analytics” (available at Webtorials), route analytics products and technology can go a long way in providing proactive network health monitoring. For instance, as the paper points out, there can be hidden problems from configuration and from logical network misconfiguration, incorrectly configured redundant links, security breaches, loss of application data, and degraded services. In many of these cases, the problem could go undetected for a long period of time because it did not trigger an active network “failure.”

The bottom line is that now that the tools are available for proactive rather than just reactive maintenance, that ounce of prevention will go a long way toward making your network more stable, resulting in increased availability and higher performance.

Read more about lans & wans in Network World's LANs & WANs section.

Steve Taylor is president of Distributed Networking Associates and publisher/editor-in-chief of Webtorials. Jim Metzler is vice president of Ashton, Metzler & Associates.