Switches can be a valuable asset to networking. Overall, they can increase the capacity and speed of your network. However, switching should not be seen as a cure-all for network issues.
Before incorporating switching into your network, you must first ask yourself two important questions: First, how can you tell if your network will benefit from switching? Second, how do you add switches to your network design to provide the most benefit?
This tutorial is written to answer these questions. Along the way, we'll describe how switches work, and how they can both harm and benefit your networking strategy. We’ll also discuss different network types, so you can profile your network and gauge the potential benefit of switching for your environment.
What is a Switch?
Switches occupy the same place in the network as hubs. Unlike hubs, switches examine each packet and process it accordingly rather than simply repeating the signal to all ports. Switches map the Ethernet addresses of the nodes residing on each network segment and then allow only the necessary traffic to pass through the switch. When a packet is received by the switch, the switch examines the destination and source hardware addresses and compares them to a table of network segments and addresses. If the segments are the same, the packet is dropped or "filtered"; if the segments are different, then the packet is "forwarded" to the proper segment. Additionally, switches prevent bad or misaligned packets from spreading by not forwarding them.
Filtering packets and regenerating forwarded packets enables switching technology to split a network into separate collision domains. The regeneration of packets allows for greater distances and more nodes to be used in the total network design, and dramatically lowers the overall collision rates. In switched networks, each segment is an independent collision domain. This also allows for parallelism, meaning up to one-half...