ROUTERS and, SWITCHES and, HUBS Oh My…

Did you ever wonder what the differences in routers, switches or hubs were? Well, even if you didn’t, I’m about to tell you. All of these devices are elements essential to networking your computers. First what’s a network? A network allows computer users to share each other’s files, printers and other resources including Internet access. You may also have a server in your network that will allow you to share files, and other resources on the server. If you don’t have a server your network is a peer-to-peer network (all computers are peers or equal in status). If you have a server in your network you are in a client/server network. The networks we’re going to discuss are Local Area Networks (LAN) e.g., the local users, Wide Area Network (WAN) e.g., remote users and/or the World Wide Web (Internet). I won’t be covering wireless network, but with few exceptions, the basics are the same (obviously there is no wire). So here we go.

Router: A router connects two networks together allowing them to pass data between the networks. The main use of a router in a SOHO environment is to allow the LAN users to access the WAN and/or access the network from home or while out of the office. A simple router will connect to your local network via a switch or hub (this could be built into the router) and to your Internet Service Provider (ISP) through a DSL, cable or analog phone line allowing all users on the network access to the Internet. Some routers may also have added features such as a built in firewall, hub or switch.

Hub: A hub, while giving multiple users access, also controls the traffic across the network. Hubs come in various configurations 4 to 48 user models. With all those users sending and receiving data (packets) from each other and from the server you would think there would be conflicts, and there is, they are called collisions (most hubs will have a collision light to make you aware of this) data packets “bumping” into each other. When this happens the user’s computer is requested to resend the data packet. Of course this happens at 10mbs, 100mbs, 1000mbs (mbs=megabits per second) depending on the speed of your network. But if you waiting on that spreadsheet to recalculate or that large file to copy it can seem like an eternity on a busy network. Fear not there is a solution. Read on!

Switch: A switch is a hub on steroids. Switches function like hubs but have store and forward buffers (memory). This simply means if you send a data packet (remember this is the information you are transmitting over the network) to the switch and another user beats you there, his/her data gets a green light and your data gets a red light. But instead of going back and starting over your data just waits in the store and forward buffer until they pass and you get the green light. All this takes place in very small increments of time that I don’t understand and makes the overall performance much faster.

WAN

LAN

In the simple peer to peer network shown above (access rights not withstanding) all computers could…

1. Access the Internet.

2. Print on the Laser Printer.

3. Print on the ASCII Printer.

4. Access data on each other’s computer.

5. Note I’ve used a hub in this example but I could have used a switch in its place.

So - this won’t make you a Network Engineer but may keep the sales/repair person from selling you something you don’t need or doesn’t do your job.

I welcome topic suggestions. Email them to soho@russell-gray.com.

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Paul Gray

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