ments document, there was literally no page for us to be on. Port Layout Spreadsheets The first step I take when designing any network is to compile a list of all the devices that will be accessing the network. In the case of LANs, here are some things to think about: How many users will the network need to support? How many servers will the network need to support? How many printers will be attached to the network, and what will their loca- tions be? What are the applications running on the network? How will users interact with these applications (HTTP, client software, terminals, Citrix)? What type of security do you need? Is high availability desired and/or affordable? What percentage of growth should we assume? Do all interfaces need to be gigabit? Documentation Will the network need to support VoIP? Will you be supporting one physical location, or many (including multiple floors in a single building)? Your goal is to come up with a target number of each interface type for each loca- tion. Once you have these numbers in mind, you can decide what sort of equipment you need to order. Gigabit Ethernet switches come in multiples of 48 at the highest port densities currently available. To determine how many 48-port switches or mod- ules you need, divide the total number of gigabit interfaces required by 48. For example, if you need 340 gigabit interfaces in one location, you'll need 340 / 48 = 7.08 (in other words, eight modules). When figuring out how many ports you need, don't forget servers that offer high availability. Many servers today will allow multiple Ether- net interfaces to be connected to one of two switches in a failover pair. Talk with your systems people, and find out what they're doing, SO you don't come up short. You should also plan for a certain amount of growth. A good rule of thumb for capacity planning is to plan for a minimum of 15 percent growth: 340 * .15 = 51. Add this to the number of interfaces currently required, then divide this number by 48 to see how many modules you'll need if you