Subnetting to Increase Performance

Subnetting to Increase Performance

Donald Shipman

Strayer University

There comes a time when a network becomes too big and performance begins to suffer as a result of too much traffic. When that happens, one of the ways that you can solve the problem is by breaking the network into smaller pieces. There are several techniques for splitting a network, but one of the most effective techniques is called subnetting. (Posey, 2005)

Subnetting allows a larger network to be split into smaller, more manageable pieces. This allows for control over increased network traffic which can degrade network performance by slowing data speeds rates. Subnetting is splitting an interconnected network in such a way that network traffic is isolated to the subnet of origination.

The main purpose of subnetting is to help relieve network congestion. Congestion used to be a bigger problem than it is today because it was more common for networks to use hubs than switches. When nodes on a network are connected through a hub, the entire network acts as a single collision domain. What this means is that if one PC sends a packet to another PC, every PC on the entire network sees the packet. Each machine looks at the packet header, but ignores the packet if it isn’t the intended recipient. Keep in mind that a switch only helps performance when a packet is destined for a specific PC. Broadcast traffic is still sent to every machine on the network. If you’re running a switched network, then subnetting will help you if you have a lot of broadcast network. Subnetting is also important if you have branch offices that are connected by a slow WAN link. (Posey, 2005)

Another consideration might be the concentration of users within a department. For example, I used to work in an office in which thousands of users all worked in a single building. For a long time, there were no external facilities. In an environment like this, you can implement subnets, but the locations for those...