Switching grows up: 10 tips for successful switching

OK, so you're sold on switching and you want to start deploying. Here are some tips to keep you on the right track from network professionals who have already taken the plunge: George Ellis, manager of network services at Cognos, Inc., a developer of database technology in Ottawa; Jaimin Patel, regional director of Predictive Systems, Inc., a network integrator in New York; and Paul Mueller, director of networking services at Schneider National, Inc., a transportation services firm in Green Bay, Wis.

Back to basics

Remember, for want of a nail, the kingdom was lost. In the realm of mission-critical computer equipment, power supplies are nails that you dare not overlook. Without power, switches are just very expensive boat anchors, so check for redundant power supplies when you evaluate them.

Hedging bets

When it comes to network capacity, users and applications are insatiable. Overprovision when you buy new equipment, and not just in terms of aggregate bandwidth. Hedge your bets, and buy more features than you need. For example, make sure you get at least four levels of queuing in core switches and at least two in the wiring closet.

Scaling limits

Don't confuse expandability with scalability. Because of the price of Manhattan real estate, some New York-based companies are finding it cost-effective to locate their server farms across the Hudson River in New Jersey. An OC-48 link provides the New York desktops with LAN-speed access. Does the technology you're considering scale to such a level? It may have to.

Skills upgrade

Switching solves some problems for you but can introduce others. The network goes a lot faster when things are working, but troubleshooting takes a lot longer when they aren't. You can't just plug a sniffer into your network and get a quick answer, so the days of using drones who just follow procedures are gone. It's a pretty safe bet you'll need to upgrade the skills of your network staff considerably.

Bigger isn't always better

Don't be overly impressed by vendors that boast about having the biggest, fastest backplane. Some of the really big platforms are missing a lot of features. Manageability, functionality and reliability are as important as speed.

Trunking traps

There is no trunking standard yet, so the Layer 3 switch manufacturers are creating their own trunking protocols in order to avoid spanning tree problems. This can result in serious compatibility problems and may even preclude multivendor configurations. If you don't want to get locked in to a single-vendor solution, ask about interoperability testing.

Uplink bottlenecks

Be sure to get enough uplink capacity. It doesn't do much good to have a massive backplane that can handle huge applications if you've got a piece of dental floss connecting the switch to your server farm. You may need 5G to 10G bit/sec of bandwidth on these trunks.

Knowledge is power

When planning an upgrade, know your environment, and know it well. Routing and bridging are fairly simple concepts that can get fuzzy when there are too many unknowns. And do a good job of baselining up front. If you want to be able to justify upgrade investments with performance improvements, such baselining is critical.

Information overload

Don't be fooled by management capabilities that extract a lot of network statistics. They may simply bury you in mountains of meaningless data. Make sure there are tools that can reduce the data to meaningful information. Don't buy switches that don't support roving port analyzers, and be wary of vendor claims about being able to manage everything from your desktop. Physical location is still very important.

Pilot first and pilot well

Conduct a thorough pilot study before embarking on any major network upgrade. Don't deploy new technology until you and your staff thoroughly understand each feature, including what it does, how it is enabled, what to expect once it is deployed and how to troubleshoot it.

Intro and What's in a Name
Prospects for ATM and Wrong Assumptions
Winners & Losers and The next Cisco? Over the Horizon and Eliminating Layer 2?