Networking and Wireless Networking

Networking allows computers to share resources. A computer resource is something that a computer has, like a file or printer. For example, you can upload your pictures from your digital camera on one PC and then view them from any PC attached to your network. Or a business can have a Word or Excel file shared by several staff members that can be viewed or updated as necessary.

What makes a network?

There are many network layouts, referred to as topologies in computer-speak, that have been used through the years. By far the most common topology used today is the star topology. In a star topology all the computers have a connection to a central point, which acts like a switchboard, passing information from one computer to the other.

There are three types of devices that can be this central point: a hub, a switch, or a router (the differences between these three aren’t important to this discussion). Today, the most commonly used device for the central point in homes and small businesses is a router, so that’s the term that will be used throughout the rest of this page.

Your router talks to an adapter on your PC called a NIC – Network Interface Card. Your NIC and your router are connected via a cable or, in the case of wireless networking, via radio waves.

So if you have a router, and you have computers connected to it, you have a network.

The Client / Server Model

Once a connection exists between the router and all of the other devices (computers, printers, etc.) data can be passed back and forth between the devices by passing the data through the router. How does one computer know what data to send, and when to send it, to another computer? Today, especially with the internet, most networking is based on the client-server model, which means you have one device that is sharing something (that’s the server) and another device that asks to use that shared something (that’s the client).

Probably the best known example of this is the World Wide Web. Let’s take the webpage that you’re reading right now. This webpage is actually a file sitting on a PC connected to the internet. That PC is doing two things, it’s willing to share this particular file and it’s running some server software. These two things make that PC a server.

Your PC is connected to the internet and is running a browser (which is a type of client software), something like Internet Explorer, Firefox or Chrome. When you click on the link that leads to this webpage, your browser (the client) sends a request over the internet to the web server (the server) that holds the page, asking for the page to be sent back. The server sends the page back over the internet to the client, which then displays the page in its window.

The client in the client / server model isn’t always the one getting the data. The client can also be the sender of the data. Let’s say you have a computer that’s sharing a printer, making it a print server. When you want to print from another PC to that printer, your client sends the data to the print server to be handled. Remember, it’s not which way the data travels that distinguishes a client from a server (since most of the time there’s data traveling in both directions) but which device is sharing a resource (the server) and which is using the resource (the client).

One final, common example is a file server. One computer on the network shares at least one folder. The rest of the computers on the network can access and update the files in that folder. An example of this in a business where several staff members may be working on a the same report. Another example is a home network where the folder that music files have been saved in is shared, potentially allowing any other computer on the network to play those music files.

Network security

Unfortunately, there are people out there who, for whatever reason, can’t be trusted. So even though there’s a great deal of convenience when you share things over a network, you have to be thinking about security. Luckily, building a secure network isn’t that hard to do, but if you’d like our assistance making your network more secure, contact us today for a free estimate.

Firewalls

The first step in securing a network is a firewall. Understanding how a firewall works is easier if you compare a firewall to people using cell phones in a magic room.

Imagine that you take your cell phone to a room where, once you are inside, you cannot receive incoming phone calls from outside the room, but you can make outgoing calls. Once you dial someone outside the room and they answer you can carry on a conversation just like any other phone call, but since they are outside the room you have to call them, they can’t call you. Now let’s imagine that if more than one person is in this room with their cell phones they can call each other, and they can call to anyone outside the room also. In other words, nobody outside the room can call a phone inside the room, but the people inside the room can call anybody whether they are inside or outside the room The room doesn’t block phone calls, it only blocks incoming phone calls.

This is exactly how a firewall works. Let’s run through an example. Say you have two computers attached to a router. The router is also connected to the internet via either a DSL or cable connection. Your router probably has a built in firewall that works (if you’ve connected everything together correctly) like the magic room described above. The two computers are “inside” the firewall (like two cell phones in the magic room) and the internet is “outside” the firewall (like all the cell phones outside of the magic room). Now you open a web browser on one of your computers. It initiates a session (makes a phone call from inside the room) with a web server on the internet (a phone outside the room) and data flows in both directions.

Let’s say, further, that you have a shared folder containing music files on one of the computers, making it a file server The other computer can bring up a client and play those music files because both computers are inside the firewall, just like people inside our magic room can call each other.

But if a computer from the internet, outside the firewall, tries to access those music files, they can’t. The file server is still sharing the files, but computers on the internet outside the firewall are blocked from initiating a session with a computer inside the firewall, just like phones outside the magic room were blocked from making phone calls into the room.

There’s a lot more to firewalls, but the above gives you a basic understanding of how things work. One last point about firewalls: there are two places where you’ll probably encounter them. One is in the router as we’ve been discussing, and the other is a software firewall inside your computer. All of the recent versions of Windows come with a firewall, and if you have any antivirus software running it might have replaced the Windows firewall with its own. These software firewalls work exactly like the firewall within your router.

Wireless Networking

Wireless networking is exactly what its name implies – networking that doesn’t use wires but instead uses radio waves. Just like wired networks, most wireless networks have devices that speak to each other through a central device called an access point. In a home or small business an access point is usually built into a router, making it a wireless router. On the PC side you also need a wireless connection (referred to as a wireless NIC). Most newer laptops come with an integrated wireless NIC, but older laptop and non-laptop PCs might need to have an adapter added, usually a USB device or a PCMCIA card.

Just because it’s called wireless networking doesn’t mean they are exclusively wireless. Usually a wireless router has wired network connections and an antenna for wireless networking, and both the wired and wireless networking occur simultaneously.

One confusing area of wireless networking is the compatibility of the many standards that exist. Wireless networking is governed by the 802.11 set of computer standards, each standard being given a different letter suffix, so you have the 802.11a standard, the 802.11b standard, and so on. When you purchase a wireless router or NIC they will be labeled with which standard they support. Many times the standard will only be referred to with the suffix letter, so you’ll see something labeled as “wireless G” meaning the 802.11g standard.

Wireless devices that support the same standard are compatible with each other.  For example, if you have a router and a table that both support wireless N, they can communicate with each other.

You can mix and match some wireless standards but not others.  An example of cross standard compatibility is wireless B devices and wireless G devices – they can communicate with each other.  An example of cross standard incompatibility is wireless A devices and wireless B devices – they cannot communicate with each other.

One important note when you mix devices from different standards is you’ll get the performance of the slower standard. So, for example, 802.11b devices have a maximum speed of 11 Mbps, and 802.11g devices have a maximum speed of 54 Mbps. If you have a wireless router that is 802.11b and a wireless NIC that is 802.11g (or vice versa) you’ll only get 802.11b speeds, or a maximum of 11Mbps.

If you’d like our assistance with wireless networking, contact us today for a free estimate.

Wireless security

The appeal of wireless networking is in its convenience – you can have your laptop anywhere within range of your wireless router and still access the internet. The problem with wireless networking lies it this same fact. More than likely you can connect to your wireless router by sitting in your car parked in front of your house or outside your office, and if you can do that somebody else can do the same thing. And, by accessing your wireless router they are inside your router’s firewall and therefore can potentially get to any shared files you have on other computers inside your firewall. If you’re going to have a wireless network you need to implement some wireless security by using some form of encryption.

There are four levels of wireless encryption for homes and small businesses:

  • Unsecured
  • WEP: Wired Equivalent Privacy
  • WPA: Wi-Fi Protected Access
  • WPA2: Wi-Fi Protected Access 2

Here’s what each means:

Unsecured: No encryption is enabled. Anybody can connect to your network as long as they are within range of your wireless router.

WEP: WEP was the original wireless encryption industry standard. Unfortunately, is was based on a simple algorithm and can be cracked easily by anybody who wants to spend a few hours learning how. While WEP is better than an unsecured network, it’s not better by much.

WPA: After WEP was cracked, there was a move to create another industry standard that was more robust. Industry standards, however, take a while to get ratified and there was an immediate need. WPA is an unofficial, de facto standard for wireless encryption and is significantly better than WEP.

WPA2: The official industry standard for wireless encryption, it is stronger than WPA.

Most newer wireless hardware will support all four options. Some older hardware will only support WEP or WPA.

One more note: WPA2 uses a more intense encryption algorithm than WEP or WPA, so some older wireless hardware slows down if you use WPA2.

There’s more to wireless security than what’s been covered here, but encryption is the first step for securing any wireless network. Don’t leave your wireless network unsecured, and don’t kid yourself by securing your network with WEP, use WPA or WPA2.

If you’d like our assistance in making sure that your wireless network is secure, contact us today for a free estimate.