With a WAN in place, employees at the LANs in any of your offices, regardless of how geographically distant they may be, can freely exchange files and data with each other as if they were physically connected to one network.

What Are the Key Components of a WAN?

Basically, a wide area network (WAN) consists of three components.

There are access routers, which are the gateway devices connected to the local area networks (LAN) . Each access router links a LAN to the WAN connection.

There are the WAN connections, which are the actual connectivity between sites. Common WAN links are public networks like the Internet, private networks such as lines leased from service providers, and the public phone system. When you use a V.90 analog modem to dial into a LAN, for example, you are using the public phone system.

The speed of a WAN connection depends on its capacity and characteristics. Analog and ISDN (Integrated Services Digital Network) links are common and inexpensive, but lack the performance of faster technologies and require a dial-up connection between sites. In other words, the link is temporary and must be re-established every time information is sent. DSL (digital subscriber line) and cable modem links are much faster and always on; these links are permanent and don’t require one modem to dial into another.

Finally, there are security strategies to prevent any unauthorized people from accessing communications between sites, particularly when they travel over public networks like the Internet.

Access Router

To connect two or more LANs together, each LAN needs a device called an access router. The access router connects to a switch or hub on the local network and serves as a gateway to the WAN. The access routers establish LAN-to-LAN connections and forward network traffic between users at the remote sites.

WAN connections

WAN traffic can travel via the Internet, the public telephone network or a private network. Internet service providers (ISPs), telephone companies and many other alternate exchange carriers provide private network connections, which are dedicated lines that your business can lease. Private networks operate independently of the public telephone infrastructure and the Internet and therefore offer the highest securit.

Connectivity over a public infrastructure is simpler to operate and less costly. Moreover, today’s security techniques can adequately protect your business information from prying eyes. A foremost security solution is VPNs (virtual private networks). VPNs create protective virtual “tunnels” through which data can travel between two locations. They safeguard business communications over a public network like the Internet.

The WAN connection you choose depends on your needs, your budget, the kinds of services you want and the types of connectivity services that are available in your region. The most common is V.90 56K analog service, which is affordable and available wherever there are public telephone lines. ISDN services are faster, but they may not be available in your area and, like analog connectivity, requires dial-in every time a link needs to be established. Broadband DSL and cable modem services offer very high performance and permanent connections, but they are not yet available everywhere. Broadband connections also require security precautions because they provide always-on access to business networks.

For low-cost, lower speed connectivity that is effective for many small organizations, deploy 56 Kbps (kilobits per second) analog access routers (actual speeds may vary, with the maximum speed limited to 53K for downloads and 31K for uploads) or 128 Kbps ISDN access routers. Install one or the other at every business office to link users on each LAN. Both solutions automatically make the dial-up connection whenever a user sends e-mail or a file, or wants to access information from a server at a remote location. Dial-up access is a common strategy among small businesses because it is reliable, inexpensive and simple to deploy.

For organizations with robust office-to-office communications needs, dial-up access lacks the faster speeds of other strategies. Moreover, since there is added delay while the integrated modems in the access router establish the connection, dial-up is less efficient when communications between offices are frequent. For these reasons, we recommend DSL for robust, enterprise-wide communications.

DSL

DSL delivers reliable, high-speed office-to-office connectivity over traditional copper wires and is available in most regions from ISPs, local phone companies or alternative exchange carriers. While a bit more expensive than 56 Kbps or ISDN access, DSL is affordable to most small businesses.

DSL is an excellent connectivity choice for WANs. In addition to delivering truly outstanding performance over existing telephone lines, DSL is an always on, or open, connection. Employees no longer have to dial-up to make a modem connection to another site (usually a router does this automatically depending on the location of the recipient). As long as their computers are connected to their LANs and their LANs are connected to each other via DSL connections, workers have instant access to the entire network. Additionally, DSL can support network telephone services.

DSL provides speeds up to a very fast 1.54 Mbps (megabits per second). There are various kinds, or “flavors” of DSL; the type you choose depends on what your ISP or phone company offers. But even the slowest DSL speed is much faster than ISDN (To learn more about DSL, take the free tutorial entitled “Understanding High Speed Internet Access Options for Business” at the 3Com Learning Center).

DSL permits you to:

• eliminate the hassle of dial-up connections
• speed the transfer of everything from e-mail and Web pages to multimedia files
• enable remote users to rapidly access and use applications at the main office
• respond to your customers’ needs more quickly
• support new users as your company grows
• and position your business to conduct e-commerce.

How does DSL provide WAN connectivity?

The most common and cost-effective way for small businesses to build DSL-powered WANs is over public networks, such as the Internet or the public telephone system. Install a DSL router at each of your offices and establish an enterprise-wide account with an ISP. Employees will have instant and easy access to the WAN.

Security

Enabling geographically-dispersed sites to freely exchange information and messages is a boon to business productivity. But you need to ensure that only your employees can access your data. Relying on a public infrastructure for office-to-office WAN communications poses a security risk for your business. Your data is traveling unprotected over an open network where it is vulnerable to hackers and others. To safeguard your proprietary, sensitive or business-critical communications, you need to deploy a VPN solution. A viable, affordable strategy for small businesses, VPNs enable data to travel in encrypted virtual “tunnels” between sites and offer very high levels of protection.

You can deploy VPNs through the use of VPN-enabled firewalls. A typical firewall is a stand-alone device linked between your access router and a switch or hub on your office network that guards your LAN. Using password and authentication techniques, it permits only those you designate to enter the network. Small business firewalls are affordable, simple to install and easy to maintain. VPN-enabled firewalls create a point-to-point VPN connection for every transmission of data sent over the WAN.