Networking: Switching to a New Design for Intelligent LAN

By Jim Metzler

August 1, 2008 —  (Page 1 of 3)

My last few columns have focused on wide area networking. One reason is that, for more than a decade, LAN design has not changed much. Since the late 1990s, LAN design has been focused on providing high-speed connectivity and very little else. Another reason for that focus on the WAN is that IT organizations tend to spend more on their WAN than they do on their LAN. That follows because the majority of LAN costs occur only once; when the LAN switches, wireless access points and wiring are installed.

In contrast, WAN costs recur monthly, and the cost of WAN connectivity increases somewhat linearly as the size of the bandwidth increases. For example, a common WAN circuit is referred to as a T1 link. A T1 link runs at 1.544 Mb/sec. If a company has a T1 link at one of its branch offices, and if it outgrows the capacity of that link and decides to add a second T1, their monthly WAN costs will double.

Given the cost of WAN circuits, when network engineers design their company’s WAN, they typically place a heavy emphasis on minimizing cost. The last few years, however, have also seen the deployment of WAN designs that incorporate additional intelligence into the WAN. For example, a number of IT organizations have deployed network optimization solutions that are designed to both reduce the cost of the WAN and to make it perform better. Future columns will discuss these solutions in detail.

In contrast to the WAN, LAN design has historically been about two things: availability and performance. However, as I mentioned in my first column, we are possibly at an inflection point relative to LAN design. In particular, many vendors are now making the claim that, similar to what has been happening in the WAN, that more intelligence must be added to the LAN to support new demands such as enhanced security.
 
At the Interop conference held in Las Vegas in April, I moderated a session that touched on the need to add intelligence to the LAN. That session was titled “Implementing Policy and Control,” and it looked at the need to implement control functions in the IT infrastructure to both improve application performance and to provide enhanced security.

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