Learn about routers, switches, and network hardware
Today we take a look at home networking hardware: what the parts do, when they're needed, and how best to deploy them. Read on to gain a clearer understanding of what you need to optimize your home network.
When do you need a switch? hub? What exactly does a router do? Do you need a router if you only have one computer? Networking technology can be a rather obscure field of study, but as long as you have the right terminology and a general overview of how devices operate on your home network, you can deploy your network with confidence.
Understand your home network with a network diagram
Rather than start with a glossary of networking terms, attacking you with technical terms with no easy reference point along the way, let's go straight to the network diagram. This is the simplest network configuration available: a computer connected directly to the modem, which in turn is connected to the individual's internet service provider via a phone line/cable/fiber uplink.
Nothing is simpler than this arrangement, but this ultra-simple setup comes at a price. The user cannot access the Internet using a Wi-Fi device (and therefore cannot use a smartphone, tablet, or other wireless device), and they lose the benefit of using a router between their computer and the larger Internet. Let's introduce routers and highlight the benefits of using them. In the image below, we introduce two elements to the network: a wireless router and a laptop connected to the network via a wireless connection.
When should I use a router? Given the low cost of a home router and the benefits of having one on your network, you should always use a router (it almost always includes firewall functionality).
A home router is actually a combination of three network components: a router, a firewall, and a switch. In a commercial environment, the three pieces of hardware are separate, but consumer routers are almost always a combination of routing and switching components, with firewalls added for good measure. First let's see what the router function does.
At the most basic level, a router connects two networks together, one inside your home (no matter how big or small) and the other outside your home (in this case, the internet). The broadband modem that your ISP gives you is only good for connecting a single computer to the internet and usually doesn't include any routing or switching capabilities. Routers perform the following functions:
- IP Sharing: Your ISP assigns you an IP address. If you have a desktop, a laptop, a TV media box, and an iPad, one IP address is obviously not enough. Routers manage these multiple connections and make sure the right packets get to the right places. Without this feature, people on desktops and laptops would not be able to browse the web at the same time, because there is no way to distinguish which computer is requesting what.
- Network Address Translation (NAT): Related to the IP sharing feature, NAT modifies the headers in packets entering and leaving the network in order to route them to the correct device. Think of NAT as a very useful receptionist in a router that knows exactly where each incoming/outgoing packet should go, and labels them department accordingly.
- Dynamic Host Configuration: Without DHCP, you would have to manually configure and add all hosts to your network. This means that every time a new computer enters the network, you must manually assign it a network address. DHCP does this for you automatically, so when you plug your XBOX into your router, your friends into your wireless network, or you add a new computer, an address can be assigned without human intervention.
- Firewall: Routers act as basic firewalls in a number of ways, including automatically denying incoming data that is not part of an ongoing exchange between computers within the network and the outside world. For example, if you request a music stream from Pandora, your router will say, "We're waiting for you, come in," and the stream will be directed to the requesting device. On the other hand, if the sudden burst of port probes comes from an unknown address, your router acts like a bodyguard, denying requests, effectively disguising your computer. Even for a user with just one computer, a simple $50 router just for firewall functionality is worth it.
In addition to the internal-to-external networking functions outlined above, a home router also acts as a network switch. A network switch is a piece of hardware that facilitates communication between computers on an internal network. Without switching, devices can communicate with the larger internet via the router, but not with each other - something as simple as copying an MP3 from a laptop to a desktop over the network is impossible.
Most routers have four Ethernet ports, allowing you to plug in four devices and have them communicate via the switch function. If you need more than four ethernet connections, you'll need to upgrade to a router with a larger port group (this is a rather expensive proposition, usually only giving you up to eight ports), or you can opt for a dedicated switch. NOTE: An upgrade is only required when the hardwired physical ports are used up. If you only have one computer and one networked printer plugged into your four-port router (and everything else on the network is Wi-Fi based), there's no need to upgrade to get physical ports. That said, let's look at a network with a dedicated switch.
While the four-port limit of the vast majority of home routers is more than enough for most home users, the number of internet-connected devices in the home has grown significantly over the past 10 years. It's not uncommon to have multiple computers, multiple game consoles, media centers, printers, file servers, etc. all connected to an Ethernet LAN (whereas you might put your Wii on a Wi-Fi network, such as dedicated video streaming and media server access, preferably with a hardwired connection). Once device saturation is reached, it's time to add a switch with 8, 16, or more ports to properly support your growing home network.
As a side note, historically people have often relied on hubs because they were so much cheaper than expensive switches. A hub is a simple network device that doesn't inspect or manage any traffic passing through it - it's a "dumb" network device - in contrast, a switch actually interacts with packets and actively directs them. Since the hub has no management components, there are frequent conflicts between packages, resulting in overall performance degradation. Hubs have a number of technical drawbacks, which you can read about here. In the past 10 years, the price of consumer-grade networking switches has dropped so dramatically that very few hubs have been produced (Netgear, one of the largest consumer-grade hub makers, doesn't even make hubs anymore). Due to the disadvantages of network hubs and the low price of high-quality consumer-grade network switches, we do not recommend the use of hubs. When you can get a really good high-speed 8-port switch for $25, there's no reason to use an outdated hub on your home network -- if you're curious why network administrators deploy hubs, you can read about it here.
Back to the topic of switches: Switches are an excellent, inexpensive way to increase the size of your home network. If the 4 ports behind your router exceed your capacity, the easiest thing you can do is buy a switch with the appropriate number of ports to expand your network. Unplug the device from the router, plug everything into the switch, and then plug the switch into the router. Note: The switch has absolutely no routing function and cannot replace the router. Your router most likely has a four-port switch built into it, but that doesn't mean your new eight-port dedicated switch can replace your router -- you'll still need the router to coordinate between the modem and the switch.
Decode network speed flags
Now that you have a clear idea of how your network should be physically configured, let's talk about network speed. There are two main names that interest us: Ethernet and Wi-Fi. Let's take a look at Ethernet first.
Ethernet connection speed is measured in 10BASE. The original Ethernet protocol is now 30 years old and has a maximum speed of 10 Mbit/s. Fast Ethernet, introduced in 1995, increased the speed to 100 Mbit/s. Gigabit Ethernet was introduced in 1998, but only recently has gained much traction in the consumer market. As the name suggests, Gigabit Ethernet is capable of 1000 Mbit/s. You'll usually see these names on network gear and its packaging, like 10/100 or 10/100/1000, indicating which ethernet version the device is compatible with.
In order to take full advantage of the maximum speed, all devices in the transmission chain need to meet or exceed the rated speed you want. For example, let's say you have a media server with a gigabit ethernet card installed in the basement and a media console with a gigabit ethernet card installed in the living room, but you use a 10/100 switch to connect the two devices together. Both devices will be limited by the 100 Mbit/s cap on the switch. In this case, upgrading the switch will greatly improve your network performance.
Aside from transferring large files and streaming HD video content over your home network, there's little need to go out and upgrade everything to gigabit. 10/100 is very satisfactory if your main computer network usage includes browsing the web and light file transfers.
Understanding Wi-Fi Speeds
Wi-Fi speeds are indicated by letters rather than numbers. Unlike the simple method of converting numbers to network speeds that we find in Ethernet, the Wi-Fi name actually refers to a draft version of the IEEE 802.11 networking standard, which specifies the parameters of the Wi-Fi protocol.
802.11b was the first version to be widely adopted by consumers. 802.11b devices have a maximum transfer speed of 11 Mbit/s, but the speed depends a lot on signal strength and quality - in practice users should expect 1-5 Mbit/s. Devices using 802.11b can experience interference from baby monitors, Bluetooth devices, cordless phones, and other devices in the 2.4GHz band.
802.11g was the next major consumer upgrade, increasing the maximum transfer speed to 54 Mbit/s (actually about 22 Mbit/s, taking into account error correction and signal strength). 802.11g suffers from the same 2.4GHz band interference as 802.11b.
802.11n is a major upgrade to the Wi-Fi standard—devices use multiple-input multiple-output antennas (MIMO) to operate on the 2.4GHz and relatively free 5GHz bands. 802.11n has a theoretical maximum of 300 Mbit/s, but with error correction and less-than-ideal conditions you can expect speeds in the 100-150 Mbit/s range.
802.11ac was a huge upgrade that brought wider channels (80 or 160 MHz vs. 40 MHz), more spatial streams (up to 8) and things like beamforming, which sent waves directly Sending to your device instead of bouncing around makes things a lot faster. How fast? There are models that can handle 1 GB per second. It's very fast.
Like Ethernet, Wi-Fi speeds are limited by the weakest link in the direct network. If you have an 802.11n-capable Wi-Fi router, but your netbook only has an 802.11g-capable Wi-Fi module, you'll hit top speeds at 802.11g speeds. Aside from speed limits, there's a very pressing reason to drop 802.11b, the oldest popular Wi-Fi protocol. You must use the same level of encryption on every device in the network, and the encryption schemes available to 802.11b devices are weak and broken (for example, WEP encryption can be broken by a moderately skilled kid in minutes). Upgrade Your Wi-Fi router and wireless devices allow you to upgrade wireless encryption and enjoy faster speeds. If you haven't done anything to protect your router right now, now is a good time to read our guide to locking down your Wi-Fi network from intrusions.
As with Ethernet, upgrading to the highest speed (802.11n in this case) is best for people moving large files and streaming HD video. Upgrading to 802.11n will have a negligible impact on your web browsing speed, but a huge impact on your ability to wirelessly stream HD content around your home.
By now, you have a grasp of how your home network is laid out, and you understand what network speeds mean and how they affect you and your network. It's time to upgrade your switch, roll out some new Wi-Fi bandwidth, and enjoy a more optimized home network.