Demystifying the WAN

Sangoma’s WAN EduKit puts experience in your hands.

• By James Carrion
• 02/01/2003

Many of you may feel comfortable supporting and troubleshooting local area networks (LANs) but cringe when it comes time to support wide area networks (WANs). Because Ethernet is such a ubiquitous LAN technology, most network admins understand the lingo of hubs, switches, NICs, 10BaseT and so on; but throw around terms such as CSU/DSU, DTE, DCE, CIR, X.25 and the average network admin, short of those who are CCNA-certified, look as though you were speaking K-PAXian. Although the Sangoma WAN EduKit isn’t a primer on learning WAN basics, it provides lab hardware that will help you get hands-on experience while you’re learning how to set up and troubleshoot X.25 or frame relay-based WANs.

Sangoma Technologies makes an interesting line of products that combines, into one card, all the physical layer technology you need to get a WAN connection up and running and turn your PC into a WAN router. Normally, to set up an X.25 or frame relay-based WAN requires purchasing components such as a CSU/DSU, a router with a serial interface and cables to connect them together. With the all-in-one card, simply install it in a PC, and the operating system sees it as another network card to which it can route packets that can then be transmitted by the integrated CSU/DSU out to the frame relay or X.25 network.

The EduKit comes with an S5142 card with a secondary mounting clip, one V.35 back-to-back cable, and drivers for Windows 98 and Windows 2000. There’s also support for Linux, FreeBSD and OpenBSD but you’ll have to download those drivers from ftp.sabgoma.com/pub. Install the card in an available PCI slot; install the secondary mounting clip, which is attached to the S5142 card by a ribbon cable; and plug the V.35 cable between the card and the mounting clip to create a pseudo loopback testing environment. At this point, you’re simulating a Data Terminal Equipment (DTE) connection to a CSU/DSU, which, in turn, is serial-connected to a Data Circuit-Terminating Equipment (DCE) via the loopback connection to the card itself.

When you run the software, you can choose to configure and test an X.25 or frame-relay connection. If you choose frame relay, two windows open: one for the DCE (called the Customer Premises Equipment or CPE) and one for the DTE (called the Access Node). You can then configure the pertinent parameters—like DLCIs, signaling, transmission rate and so on—to create a frame relay permanent virtual connection (PVC).

When running the X.25 labs, two windows also pop up, one for the DTE and one for the DCE. You have the same configuration and troubleshooting abilities, including being able to run a line trace. Although the interface may be straightforward to the WAN expert, online help is nonexistent so you’ll have to rely on reading the online lab manuals to familiarize yourself with running lab tests.

You’ll need a good solid background in WAN theory in order to understand and maximize the use of this kit. If you’re a WAN newbie, you may want to check out the excellent free WAN educational materials available on the Internet, for example, at www.marconi.com/html/education/webbasedwantheory.htm.

Getting a grasp of WAN concepts is no easy task—especially if you don’t have the opportunity to perform hands-on configuration at your workplace. Sangoma offers a unique product that will help you reinforce the WAN theory you’ve learned in the classroom environment. Put the lab exercises through the paces and soon you’ll be spouting off WAN terminology that will make others notice your technical prowess.

WAN EduKit, $549 for U.S.-certified educational institutions, $849 for all others; Sangoma Technologies, (905) 474-1990, www.sangoma.com.