Network Devices

Okay, so I was talking to a few friends today about networking, and I decided to introduce them to it.
After explaining the general concept behind computer networking, I felt there was a need to show them a few devices and explain what those devices do.

Well, networking is made possible by connecting devices together, and these devices are simply called network devices.

Examples of network devices are: Hubs, Switches, Routers, Access Points, Firewalls, etc.

Let me briefly talk about each of the above mentioned devices.

Hubs: Think of a hub like a cable with ports on it. Hubs really don't do anything apart from broadcasting whatever they receive to everyone connected to it. A hub is NOT intelligent, since it can not make decisions on whether or not to forward the data it receives; it just sends it to everyone.

Switches: A switch can sometimes be called an intelligent hub. This device is still one of the most widely used network devices today. A switch has three main functions:

1. Address Learning - This is usually the first thing a switch does before it can perform its other functions. Switches learn addresses called MAC (Media Access Control) Addresses, which is really a unique address for every network capable device. Once a switch has learnt addresses connected to it through its ports, then it is easy to forward data to only the intended recipient, as opposed to forwarding data to everyone (like a hub does)

2. Forward & filter frames - A switch can filter frames, as well as forward it if no filtering is required. Meanwhile, a frame is what data is called at the point where it encounters a device such as a switch. More details about that later.

3. Loop avoidance - A switch has a way of making sure that there are no loops in data transfer. This characteristic makes it a much more preferable device than a hub, since certain things (which will be talked about later) can be done to determine what is sent, and where it should be sent to.


Routers: A router is a device that connects various networks together. It has 4 main functions:

1. Packet Switching - A router can easily switch a packet from one point to another.

2. Packet Filtering - A router can filter packets, and decide whether or not to forward them.

3. Path selection - A router can weigh various options, and determine the best path through which a packet should be sent in order to get to its destination safely.
*Meanwhile, a packet is what data is called at the point where it encounters a device such as a router*

4. Internetwork communication - Once a router is connected to more than one network, it can allow users on different networks to communicate and share resources.

Access Points: An access point, widely known as Wireless Access Point, is a device that allows users to connect to a network wirelessly. This means that users do not need to connect through network cables in order to access the resources that are being shared on a network.

Firewalls: A firewall is a security device that either permits or denies data traffic to a network. A firewall can be configured to accept/deny traffic based on different criteria; and this is usually dependent on the security policy of the organization involved.


So, you can see how interesting it is just knowing about some of these devices. After talking about these to my friends, I could see smiles on their faces, and I'm sure you've gained enough to put one on your face too.

Feel free to ask questions and make contributions.