Cable & wireless networks

When it comes to home networking, there's a soup of technical terms, LAN, WAN, broadband, Wi-Fi, CAT5e, just to name a few. If you're having a hard time with these basic terms, you're reading the right post. Here I'll (try to) explain them all so that you can have a better understanding of your home network and hopefully a better control of your online life. There's a lot to explain so this long post is just the first of an evolving series.

Advanced and experienced users likely won't need this, but for the rest, I'd recommend reading the whole thing. So take your time, but in case you want to jump to a quick answer, feel free to search for what you want to know and chances are you will find it within this post.

1. Wired networking

A wired local network is basically a group of devices connected to one another using network cables, more often than not with the help of a router, which brings us to the very first thing you should know about your network.

Router: This is the central device of a home network into which you can plug one end of a network cable. The other end of the cable goes into a networking device that has a network port. If you want to add more network devices to a router, you'll need more cables and more ports on the router. These ports, both on the router and on the end devices, are called Local Area Network (LAN) ports. They are also known as RJ45 ports or Ethernet ports. The moment you plug a device into a router, you have yourself a wired network. Networking devices that come with an RJ45 network port are called Ethernet-ready devices. More on this below.


Note: Technically, you can skip the router and connect two computers directly together using one network cable to form a network of two. However, this requires manually configuring the IP addresses, or using a special crossover cable, for the connection to work. You don't really want to do that.


The back of a typical router; the WAN (internet) port is clearly distinguished from the LANs.

 

LAN ports: A home router usually has four LAN ports, meaning that, straight out of the box, it can host a network of up to four wired networking devices. If you want to have a larger network, you will need to resort to a switch (or a hub), which adds more LAN ports to the router. Generally a home router can connect up to about 250 networking devices, and the majority of homes and even small businesses don't need more than that.

There are currently two main speed standards for LAN ports: Ethernet (also called Fast Ethernet,) which caps at 100 megabits per second (or about 13 megabytes per second), and Gigabit Ethernet, which caps at 1 gigabit per second (or about 150 MBps). In other words, it takes about a minute to transfer a CD's worth of data (around 700 MB or about 250 digital songs) over an Ethernet connection. With Gigabit Ethernet, the same job takes about five seconds. In real life, the average speed of an Ethernet connection is about 8 MBps, and of a Gigabit Ethernet connection is somewhere between 45 and 100 MBps. The actual speed of a network connection depends on many factors, such as the end devices being used, the quality of the cable and the amount of traffic.

Home networking explained

Rule of thumbThe speed of a single network connection is determined by the slowest speed of any party involved.

For example, in order to have a wired Gigabit Ethernet connection between two computers, both computers, the router they are connected to and the cables used to link them together all need to support Gigabit Ethernet (or a faster standard). If you plug a Gigabit Ethernet device and an regular Ethernet device into a router, the connection between the two will be capped at the speed of Ethernet, which is 100 Mbps.


In short, LAN ports on a router allow Ethernet-ready devices to connect to one another and share data.

In order for them to also access the internet, the router needs to have a Wide Area Network (WAN) port. On many routers, this port may also be labeled the internetport.

A typical CAT5e network cable.
A typical CAT5e network cable.

Switch vs. hub: A hub and a switch both add more LAN ports to an existing network. They help increase the number of Ethernet-ready clients that a network can host. The main difference between hubs and switches is a hub uses one shared channel for all of its ports, while a switch has a dedicated channel for each one. This means the more clients you connect to a hub, the slower the data rate gets for each client, whereas with a switch the speed doesn't change according to the number of connected clients. For this reason, hubs are much cheaper than switches with the samenumber of ports.

However, hubs are largely obsolete now, since the cost of switches has come down significantly. The price of a switch generally varies based on its standard (regular Ethernet or Gigabit Ethernet, with the latter being more expensive), and the number of ports (the more ports, the higher the price).

You can find a switch with just four or up to 48 ports (or even more). Note that the total of extra wired clients you can add to a network is equal to the switch's total number of ports minus one. For example, a four-port switch will add another three clients to the network. This is because you need to use one of the ports to connect the switch itself to the network, which, by the way, also uses another port of the existing network. With this in mind, make sure you buy a switch with significantly more ports than the number of clients you intend to add to the network.

Wide-area network (WAN) port: Also known as the internet port. Generally, a router has just one WAN port. (Some business routers come with dual WAN ports, so one can use two separate internet services at a time.) On any router, the WAN port will be separated from the LAN ports, and is often distinguished by being a different color. A WAN port is used to connect to an internet source, such as a broadband modem. The WAN allows the router to connect to the internet and share that connection with all the Ethernet-ready devices connected to it.

Broadband modem: Often called a DSL modem or cable modem, a broadband modem is a device that bridges the internet connection from a service provider to a computer or to a router, making the internet available to consumers. Generally, a modem has one LAN port (to connect to a router's WAN port, or to an Ethernet-ready device) and one service-related port, such as a telephone port (DSL modems) or a coaxial port (cable modems), that connects to the service line. If you have just a modem, you'll be able to connect just one Ethernet-ready device, such as a computer, to the internet. To hook up more than one device to the internet, you will need a router. Providers tend to offer a combo device that's a combination of a modem and a router or wireless router, all in one.

Network cables: These are the cables used to connect network devices to a router or a switch. They are also known as Category 5 cables, or CAT5 cables. Currently, most CAT5 cables on the market are actually CAT5e, which are capable of delivering Gigabit Ethernet data speeds (1,000 Mbps). The latest network cabling standard currently in use is CAT6, which is designed to be faster and more reliable than CAT5e. The difference between the two is the wiring inside the cable and at both ends of it. CAT5e and CAT6 cables can be used interchangeably, and in my personal experience their performance is essentially the same. For most home usage, what CAT5e has to offer is more than enough. In fact, you probably won't notice any difference if you switch to CAT6, but it doesn't hurt to use CAT6 if you can afford it to be future-proof. Also, network cables are the same, no matter how they shape, round or flat.

Now that we're clear on wired networks, let's move on to a wireless network.

2. Wireless networking

A wireless network is very similar to a wired network with one big difference: Devices don't use cables to connect to the router and one another. Instead, they use radio wireless connections called Wi-Fi (Wireless Fidelity), which is a friendly name for the 802.11 networking standards supported by the Institute of Electrical and Electronics Engineers (IEEE). Wireless networking devices don't need to have ports, just antennas, which are sometimes hidden inside the device itself. In a typical home network, there are generally both wired and wireless devices, and they can all talk to one another. In order to have a Wi-Fi connection, there needs to be an access point and a Wi-Fi client.

Basic terms

basic terms

Each of the Wi-Fi networks that a client, such as an iPhone, detects generally belongs to one access point.


Access point: An access point (AP) is a central device that broadcasts a Wi-Fi signal for Wi-Fi clients to connect to. Generally, each wireless network, like those you see popping up on your phone's screen as you walk around a big city, belongs to one access point. You can buy an AP separately and connect it to a router or a switch to add Wi-Fi support to a wired network, but generally, you want to buy a wireless router, which is a regular router (one WAN port, multiple LAN ports and so on) with a built-in access point. Some routers even come with more than one access point (see discussion of dual-band and tri-band routers below).

Wi-Fi client: A Wi-Fi client or WLAN client is a device that can detect the signal broadcast by an access point, connect to it and maintain the connection. All recent laptops, phones and tablets on the market come with built-in Wi-Fi capability. Older devices and desktop computers that don't can be upgraded to that via a USB or PCIe Wi-Fi adapter. Think of a Wi-Fi client as a device that has an invisible network port and an invisible network cable. This metaphorical cable is as long as the range of a Wi-Fi signal broadcast by an access point.


Note: The type of Wi-Fi connection mentioned above is established in the Infrastructure mode, which is the most popular mode in real-life usage. Technically, you can skip an access point and make two Wi-Fi clients connect directly to each other, in the Adhoc mode. However, as with using a crossover network cable, this is rather complicated and inefficient.


Wi-Fi range: This is the radius an access point's Wi-Fi signal can reach. Typically, a good Wi-Fi network is most viable within about 150 feet from the access point. This distance, however, changes based on the power of the devices involved, the environment and (most importantly) the Wi-Fi standard. The Wi-Fi standard also determines how fast a wireless connection can be and is the reason Wi-Fi gets complicated and confusing, especially when considering the fact there are multiple Wi-Fi frequency bands.

Frequency bands: These bands are the radio frequencies used by the Wi-Fi standards: 2.4 GHz and 5 GHz. The 2.4 GHz and 5 Ghz bands are currently the most popular, collectively being used in all existing network devices. Generally, the 5 Ghz band delivers faster data rates but a little less range than the 2.4 Ghz band. Note that a 60 GHz band is also used but only by the 802.11ad standard, which is not yet commercially available.

Depending on the standard, some Wi-Fi devices use either the 2.4 GHz or the 5 GHz band, while others that use both of these are called dual-band devices.