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Bulletproofing a wide area network might not sound easy, but there are a number of ways to fortify the links in the chain that
keeps your WAN connected.
Remember the chain letter, that cryptic correspondence recipients are urged to pass on to others lest they suffer ill fortune? A wAr is not unlike a chain letter: When a link is broken, bad luck is sure to follow.
One way to fortify these links is to ensure that your WAN is fault-tolerant. Many associate fault tolerance with the local area network, but it's equally crucial on the WAN.
In this article, I'll detail some design, implementation, and service options that can help you construct the most resilient WAN possible, or improve the fault tolerance of your existing one.
THE COST OF CONNECTIVITY
Problems can occur at various links in the chain of systems and services that make up a WAN. As WANS become more complex, there are more nooks and crannies in which these problems can hide.
Whether you're starting from scratch or upgrading, the key to fault tolerance on the WAN is ensuring that each link in the chain is strong, flexible, and, if possible, duplicated. Doing your homework is the only way to eliminate snafus such as single points of failure.
Part of this homework involves economics. Susan Almeida, vice president of consulting services at Strategic Networks (Boston), compares assessing WAN connectivity to peeling an onion. "There are many layers where you [need to decide] whether a further investment in redundancy for a given component, or `layer,' is worth it," she says.
Cost issues can also become political issues, in the quest to meet a company's technological and financial needs.
You need to consider several factors when determining how much redundancy you can afford for your WAN. To begin with, you must determine the exact value of the applications you plan to run over the wAN, and how crucial they are to your business. You must also assess the cost of the equipment and services you need to create an effective, redundant configuration.
The most basic components you need to factor in to your wAN budget are commonsense safeguards such as hot failover, dual power supplies, and backup NICS, all of which...