Introduction to routers – electricity and circuits test


In a nutshell: A router is a networking device (a box) that allows multiple computers/phones/tablets/etc. to share a single Internet connection. In the old days the sharing was only via wired Ethernet cables, now, every consumer router offers both Ethernet and wireless Wi-Fi access.

A router does not talk to an Internet Service Provider (ISP), that job is handled by a modem. Different types of Internet connections (DSL, cable, optical (such as FIOS), dial-up and Satellite for example) require different types of modems. While the (logical) front end of these different types of modems varies drastically, they all offer an Ethernet connection on the (logical) back end. This Ethernet port serves as the input to a router. Thus any router can work with any type of Internet connection.

While you can plug a computer into the Ethernet port of a modem, it’s a waste. A high speed connection wants to be shared :-). The only time we would do this is when there is a problem with the Internet connection and we are trying to figure out if the problem is with the modem or the router. It is also a bit dangerous.

A router also provides a firewall to prevent computers on the Internet from making unsolicited connections in to any of your computing devices. With a good router this firewall will offer full protection. On a bad router there will be some holes poked in the firewall. The Test Your Router page offers many ways to kick the tires on the firewall in your router.

A typical router will offer four Ethernet ports for your computers. As Wi-Fi has become more popular, some consumer routers have only one Ethernet port. High end routers offer more than four ports. The number of Ethernet ports can be expanded with a device called a switch. A switch does for computer networks what a power strip does for electricity. Just as you plug a power strip into an electric wall socket, you plug a switch into an Ethernet port of the router. The smallest, cheapest switches have four Ethernet ports, more expensive units offer many more ports.

All routers sold to consumers offer Wi-Fi, the only models without Wi-Fi are for business use. A router can create a varying number of wireless networks, each with its own name (SSID) and security profile. Pretty much every router can create at least two wireless networks, one for private use and one for Guests. Asus routers can create eight wireless networks. My favorite router can create three networks. If need be, the wireless feature can be disabled in a router.

I talk about routers and modems being separate and independent devices. Sometimes they are, sometimes they are not. ISPs often ship their customers a single box which functions as both the modem and the router. The official term for this is a " gateway" but, very often, a gateway is incorrectly called a router or a modem. Even techies make this mistake in terminology. Sometimes they are referred to as "Modem Routers".

From a Defensive Computing standpoint, you are better off with separate devices for a number of reasons. For one, having two devices lets you update or replace either one without impacting the other. And, it lets you chose the best of breed for each device. If nothing else, it lets you opt for a more up-to-date device, or, a more secure one. It also makes debugging easier when things go wrong. Finally, buying your own modem and/or router can save you money in the long run.

The term modem derives from modulating and demodulating, something that modems don’t actually do. When the Internet first became popular, computers dialed the telephone to get online. The hardware that handled this communication was called a modem. Modulating refers to translating digital ones and zeros into tones that a telephone line can transmit. Demodulating is the reverse. When newer technology, offering faster connections, came out, we needed a term for the box in your home/office that handled these newer types of communication. Thus "modem" came to mean the device that talks to your ISP, regardless of the technology it uses.

You may also hear the term access point. This refers to a box that does Wi-Fi and nothing but Wi-Fi. An access point has to be connected to a router, usually by Ethernet. High end networking equipment allows for many access points to connect to a single router. The term is often abbreviated to just AP. They are also known as Wireless Access Points or WAPs.

Starting in early 2016 we saw new devices – mesh router systems. These were routers sold as a set of three boxes. One box connects to the modem via Ethernet and the other two offer a much expanded Wi-Fi range. The two satellite Wi-Fi devices connect to the base station either by Wi-Fi or Ethernet. Some of the mesh systems are designed to replace a router, others are more flexible, and will work with an existing router to expand its Wi-Fi range. While the first wave of mesh router systems were all three-packs, some now are two devices and others support four or more devices.

There are typically five Ethernet ports on a router. Four are LAN ports — LAN means Local Area Network. In English, LAN refers to the network in the same location as the router. If the router is in your home, the LAN refers to the network in your home. The other Ethernet port is the WAN port. WAN means Internet, although it stands for Wide Area Network. If you have a separate modem and router, the (one and only) Ethernet port from the modem is connected to the WAN port on the router.

The LAN ports are normally numbered 1 through 4 and they are all the same. That is, it makes no difference which LAN port anything is plugged into. There may be an exception to this rule, if you use QOS (Quality of Service) to give one port a higher priority than the others. But that’s not a security issue.

Most routers do not have an on/off switch. Many of those that do, position it such that its just as easy to pull the electric plug as it is to hit the button. Almost all have lots of pretty blinking lights, but the number of lights and what they indicate vary greatly. Some routers let you disable the blinking lights.

the most expensive, at $350 as of early May 2016. Then the Linksys EA9500 was released in late May 2016 at $400 (its tri-band, 5.3Gbps MU-MIMO). The Netgear Nighthawk X10, a single router, was released in October 2016 for $500. The Eero mesh network system of three devices was released in early 2016 for $500 and

Apple routers can only be configured from an Apple device (iOS or OS X) running the Apple AirPort utility. Technically, Apple does support Windows, in that there is an edition of the AirPort utility that runs on Windows, but it has not been updated for a very long time. In the old days Apple routers could talk to network software via SNMP (Simple Network Management Protocol), but no more.

Some routers have a touch screen interface. Amped Wireless was, I believe, the first to market with this. Their TAP-R2, TAP-R3 and Securifi Almond+ all feature touch screens. So too, does the Starry station router and the Ubiquiti AmpliFi series, shown here at the right. The AmpliFi has been adding new features to its touch screen. You can even use it to upgrade the firmware.

No doubt, smarphone apps are the wave of the future when it comes to communicating with a router. As noted above, Google exclusively uses a smartphone app to communicate with its router, as do Eero and others. The aforementioned Netgear Genie software, also runs on iOS and Android. Peplink has smartphone apps for iOS and Android, but they are not nearly as full featured as the web interface of their routers.

Eero routers, after plugging them into a modem, pair up with a smartphone over Bluetooth for the initial setup procedure. This is becoming more common. Luma does it too and the upcoming Portal router (expected later in 2016) will also work this way.