There are three basic devices that are utilized to run a network. Depending on the size of your network these devices may be combined into one device. In most small networks this is the case. For example, if you utilize a DSL or FiOS connection it is likely that you will have an integrated device. Let’s talk about the three different types of devices:

Routers

Routers are used to communicate between networks. A router has intelligence in that it is able to read IP addresses and direct network traffic (packets) to the correct location. Generally your router is provided by your Internet Service Provider (ISP). It is the last device that is “yours” before you reach the internet.

If you are buying a router, Cisco is well-known for their routers. Vyatta is a newer company offering open source routers and Untangle is a combination device that is open source and can handle routing.

Switches

Switches generally are small devices that have lots of ports that accept network cables. It is the backbone of any network as it provides a central place of connection for all the different devices on the network. While one can use archaic devices such as hubs, there is very little reason to do so. Switches offer advantages such as isolating traffic – rather than sending the traffic to every computer on the network. Numerous companies offer switches. At the small business level you can purchase these from NetGear, Linksys, or Belkin. At the larger corporate level where performance and redundancy are paramount you can purchase them from companies such as Cisco and HP.

Firewalls

Firewalls provide a method of allowing or preventing devices from sending any or certain communications to your LAN. This is important in preventing data compromise by individuals such as hackers who attempt to exploit the communicative nature of the internet. The standard firewall (are you seeing a pattern here?) would be Cisco’s ASA series. Alternatively, you might consider an open source option such as Untangle.

Generally speaking your router will plug into your ISP’s connection. Your firewall will plug in to your router and your switch will plug into your firewall. All other devices will plug into the switch.

Further Reading

• Book: Ethernet Switches (Charles E. Spurgeon and Joann Zimmerman).
• Book: Packet Guide to Routing and Switching (Bruce Hartpence).
• Book: Packet Guide to Core Network Protocols (Bruce Harpence).
• Book: Network Warrior 2nd Ed. (Gary A. Donahue).