Network Crash Course – Routers and Switches

If servers are like the brains of your network then the switches and routers are the backbone, carrying all the information on your network and making sure it gets to where it is supposed to go. In my time as an IT Pro I have seen this equipment grow from a simple ring of cable chaining a group of devices together to sophisticated equipment that moves data at high speeds and prioritizes traffic based on the type of data that is being sent. Today without routers and switches there would be no networks and no Internet.

Let’s talk about what a switch does. Basic un-managed switches receive packets of data from a device like a server, printer, or computer then using a list it keeps in its memory shoots that packet of data out the port that the intended target of the data is on. Sometimes there are multiple switches between where a packet starts and where it is destined to end up. In this case the switches have to also keep track of if the device is somewhere beyond another switch. Smart switches and managed switches have a host of features that allow a network pro or engineer manage and improve the quality of service on the network or secure groups of traffic and separate them from each other. The latter is important both for security and performance. One example of how using a smart or managed switch can improve security is this: You have a network with your workstations and your server on it and you have financial data for clients on that network. A contractor like an accountant or other business consultant comes in to do some work for your company and they need access to the internet. You have an extra desk and a cable for them to plug their computer into. They do so but their computer is infected with a virus that is able to collect data from your server and computers. It is relatively easy for the virus to do its work because it is directly connected to all the other devices on your network. With a smart switch or managed switch you can wall this one port off from the rest of the network and only allow access to the internet protecting your clients’ valuable data. This is just one of the benefits and features of using a smart or managed switch. Another is that generally they use better components and have faster internal speeds than a basic switch. If you have outside parties accessing your network either wired or wirelessly I highly recommend at least using smart switches in your network. Also if you are thinking about making the switch to VOIP phones a smart switch can allow you separate the voice traffic from your regular data traffic helping to prevent slowdowns on your network. Smart and managed switches require some configuration so like any other device it is a good idea to back up that configuration and back it up again any time it changes. The software on these smarter devices can and should be updated when the manufacturer releases updates. These updates are usually to fix issues or glitches in the software, security or otherwise but can also give the switch access to new features.

A router allows you to take multiple networks that are separated either physically or by software (like I discussed above in the example I gave for smart switches) and pass data between them. Most small and medium sized businesses only have one router on their network and it generally allows their network to connect to the internet. Routers can be set up to only allow certain traffic to go from one network to another and block everything else. Similar to switches routers keep a list, but instead of devices it is a list of networks. This list allows the router to keep track of what port it should send data out in order for it to reach its destination. Keeping with the previous example the router knows about the separate network your guest is on, the internet, and the network all of your devices are on. The router is configured to allow data from the guest network to get to the internet but not to your network. The router also lets your internal network access the internet but nothing from the internet is allowed to come into either network unless it was requested by a device on that network. You can think of a router like a border patrol checkpoint where multiple countries meet. It asks where are you going, why are you going there, and are you carrying anything you shouldn’t. That reminds me — routers have also taken on the role of integrating with firewalls and other next gen security tools. This means that they don’t just ask what is in your digital trunk; they search it, test it, and seize it before sending you on your way. This inspection helps to protect your network from viruses and attackers before the infected data ever gets to your computers. Like the smart and managed switches the software on routers gets updated several times throughout the device’s life. You should keep this software up to date and back up the configuration. Keeping the software up to date is especially important if you are using the advanced firewall features because that could mean the difference between something bad getting in and it being blocked.

Routers and switches can last a long time in your network because the only moving part is the fan. Heat and dust are the 2 major reasons these devices break so they need to be installed in a cool dust free location. Just because the switch is still working though doesn’t mean it should still be in your network. Most routers and switches go out of support or EOL (End-Of-Life) at some point. This is when the manufacturer will no longer provide support or software updates for the device. If your router or switch has been EOL for a year or more it is way past time to replace it. Like Windows XP, when hardware reaches its EOL it becomes a liability. If you have had a switch or router for 5 or 6 years and it is still supported by the manufacturer you might still want to begin planning on replacing it with newer hardware. The electronics in the device after running several years non-stop are likely to experience degraded performance and are, in my experience, more likely to fail. After 5 or 6 years the technology in new switches and routers has changed enough that you are likely to also get substantial benefits in speed, quality, and improved features by replacing your routers or switches. Don’t wait for your routers or switches to fail — this only leads to lost productivity. Have a plan in place for proactively maintaining your network hardware and replacing it as features and performance improve in newer equipment.

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