5.4 Network Hardware: Routers

Basics​

You’ll control the traffic on your network and data packets going to and from your network using routers and switches. The most common job of a router is to manage traffic between networks, such as forwarding data from your internal local area network (LAN) to a wide area network (WAN), like to your ISP (Internet Service Provider). Some large networks may have multiple LANs that connect to form its own WAN which would then require multiple routers, one for each LAN.

You should know the following terms:

  • Local area network (LAN)
  • Wide area network (WAN)
  • Routing
  • Switch
  • Router
  • Default gateway
  • Routing tables
  • Load balancing
  • Dynamic versus static routing

Routing determines the path packets of data will take as they are transferred across one or more networks. Routing uses addressing protocols to identify where to send data when it is received. 

Local data transfer within your LAN (Local-Area Network) occurs through a switch or multiple switches. Data packets cannot go beyond your LAN through a switch. That requires a router. A router connects two or more IP networks or subnetworks so that data can be transferred out of or into your LAN from a larger network, like the Internet. Routers are very often used to host the default gateway on your network, which is the beginning and ending point of your LAN. Because routers are the gateway to your network, they are susceptible to malware attacks. Their firmware should be updated regularly to the most current version and you may rely on external services to mitigate attacks like denial-of-service (DDoS) attacks.

Routers determine the most efficient path to transfer information to its final host destination using internal routing tables. The most efficient path is not always the shortest path, if that path has more traffic than other options. By managing network data traffic, routing can transfer data more quickly and can help prevent server crashes due to too many users following the same path. 

Sometimes routers may send copies of data packets on different paths to try to reduce errors due to data losses and to manage traffic volume. This is referred to as load balancing. Routers can forward millions of data packets millions of times per second.

Dynamic routing allows the software on the router to determine the best path to deliver data packets. The software is able to monitor network traffic and adjust the route if there are any issues with traffic, such as slow downs or breaks between links. Just as with DHCP, using dynamic routing is preferred over static routing in which a technician manually determines and configures network routes. They must also monitor and update routes in the case of broken links or excessive traffic. Static routing requires less computing power and may be preferred on small networks, but the size of school networks would most likely benefit from dynamic routing.

Here are additional resources you may find useful:

Complete the following task or self-assessment:

  • Become familiar with the basic operations of the router(s) on your network.
  • Identify vendor manuals or websites that show how to configure and troubleshoot routers.
  • Determine how to update the firmware of your routers. 

Your access to the routers on your network may be limited, but at some point you should feel comfortable maintaining and troubleshooting them.