CompTIA’s product-neutral Network+ exam tests your skills outside the Microsoft mold. Here’s your guide to preparation.

Network Detailing

CompTIA’s product-neutral Network+ exam tests your skills outside the Microsoft mold. Here’s your guide to preparation.

• By Greg Neilson
• 11/01/2000

Whether you’re an experienced network professional or somebody new to the IT biz, the Network+ test from CompTIA, released last year, offers an excellent jumpstart to your certification efforts. CompTIA is a high-tech vendor consortium that offers non-product-specific exams. The organization cut its teeth on the A+ test, which is aimed at proving the expertise of help desk technicians. Network+ does the same thing for those in the networking profession. And some vendors—including Microsoft—consider it a great foundation for continuing onto premium certifications, such as the MCSE. I recently tried the beta version of this exam. Why a beta version, you ask? By testing new questions, CompTIA can seed its live exam with new items or come out with a new version altogether.

The certification is intended to test the working knowledge of a networking professional with 18 to 24 months of experience. As well as some basic theory—the OSI reference model layers and the 802.x standards—much of the exam is practical in nature. You’ll need to be conversant in all aspects of TCP/IP: addressing, subnetting, standard ports, configuration, standard applications, and also trou-bleshooting tools. In the article I highlight the main areas you need to master in your preparation for the Network+ test.

Knowledge of Networking Technology

How well do you understand what each of the seven layers of the OSI Reference model does? Let’s review them.

• Physical. Defines the electrical characteristics of network communication.
• Data Link. Defines the standard frame layouts.
• Network. Breaks the network up into logical network segments, through which data can be routed to reach other segments.
• Transport. Ensures the reliability of data; it handles flow control, acknowledgments, and sequence numbering.
• Session. Establishes and maintains the dialog between two communicating systems. RPCs reside here.
• Presentation. Works with the data formats, for example, character-set conversions, compression, expansion, and encryption/decryption.
• Application. The interface with the user.

One other theoretical area you need some understanding of is the Institute of Electrical and Electronic Engineers (IEEE) 802.x specifications, which covers the Physical and Data Link layers. There are many of these that cover things such as voice/data integration and wireless networking, but the three most important are:

• 802.2, Logical Link Control (LLC), which subdivides the Data Link layer in two: LLC and the lower MAC (Media Access Control) sub-layer. This means that the LLC functionality can be shared regardless of the underlying topology such as Ethernet or Token-Ring.
• 802.3, Ethernet.
• 802.5, Token-Ring.

Tip: As well as these layers, a network professional should understand the options available for network connectivity and the layers of the model these operate within. For example, a bridge operates at the data link layer whereas a router operates at the network layer. A brouter is a combination bridge and router; it can operate at both the data link and network layers.

Another technical topic we all hold dear to our hearts: the different classes of IP addressing and the default subnet mask each has. Table 1 shows the details you should know. The subnet mask tells you which parts of the IP address in the x.x.x.x dotted decimal notation represent the network address and which represent the node address. The rule is that when the subnet is converted to binary, the network address is in ones and the node address is in zeros. So you can see that a class A address uses the first octet, or byte, for the network address, with the remainder being the node address. Similarly, a class C address uses three bytes for the network address and leaves one byte for the node address.

The TCP/IP protocol suite has a number of standard ports assigned to applications, many of which you should know. A common problem that can occur in practice is that these ports are blocked by a router, preventing a user from getting to a given application. Table 2 shows the main ports you need to be aware of.

Also make sure you know how to work with the main TCP/IP utilities: ARP, NBTSTAT, TRACERT, NETSTAT, IPCONFIG/WINIPCFG, and PING. Spend time reviewing what these commands do, when to use them, and the purpose for the various optional parameters for each command.

Tip: It can be useful sometimes to continuously PING a host, since the default PING behavior is to only send four packets and stop and report the results. I use this often when performing remote reboots of servers since this lets me know when the server has actually finished shutdown (it stops responding to PING) and when the operating system has started again (it starts responding again to a PING). In order to do this, you use the -t option with PING. In this case, you use Ctrl-C to stop sending PINGs.

Given the practical nature of the exam, you need to understand how you actually configure TCP/IP on a client and what each of the main configuration parameters actually means—the IP address, the subnet mask, and the default gateway. For example, the client sends to the default gateway all packets not on the same network for which it doesn’t have an explicit route already configured.

You also need to know about other common network protocols: NetBEUI, IPX/SPX, and Appletalk. For example, NetBEUI uses names to identify resources on the network, and it can’t be routed—it can only be bridged. In a manner analogous to DNS and HOSTS files, WINS and the LMHOSTS files map NetBIOS names to IP addresses.

You’ll need a working knowledge of Windows NT and Novell NetWare concepts. You aren’t expected to be an expert, but you should understand the way these operate on a network. For example, NT 4.0 can use TCP/IP, IPX (which it calls NWLink), and NetBEUI. IPX is traditionally associated with NetWare, but now NetWare 5.x can use TCP/IP natively. IPX can be routed, and each network segment is given an IPX address. Servers have a unique internal IPX address, and clients have an individual station address created by the combination of the burnt-in MAC address from their network adaptor and the network IPX address.

After I took the exam, I realized that there were a number of areas in the exam objectives that were covered lightly, if at all. However, these may well be part of the exam you take so you can’t afford to ignore them. These include an understanding of star, bush, mesh, and ring topologies and also high-availability/fault-tolerance options such as mirroring, duplexing, striping, volume (sets), and tape backup.

Knowledge of Networking Practices

How good are you at troubleshooting? If you were presented with a short scenario and then asked what steps should be taken next, would you feel confident in your choices?

Much of troubleshooting is common sense—you eliminate the possibilities in a logical fashion. For example, if a user has a network problem, you need to determine whether other users have the same problem or whether it’s limited to that user, or perhaps limited to users on the network segment.

If you read carefully through the exam objectives for the Troubleshooting the Network section, it guides you through the processes the test creators want you to follow when answering the questions. For some of us who have been doing this for a while, this will be old news, but if you’re just starting out, listen up. Learning how to find the source of a problem systematically could be a more useful professional skill than any of the technical content in the exam. For example, I’ll quote objective 11.3.3 to illustrate this:

Identify the following steps as a systematic approach to determining whether a problem is attributable to the operator or the system, and given a problem scenario, select the appropriate next step based on this approach.

1. Have a second operator perform the same task on an equivalent workstation.
2. Have a second operator perform the same task on the original operator’s workstation.
3. See whether operators are following standard operating procedure. Use this approach when asked in the exam which problem-solving step should come next in the situation presented.

Tip: Check through the exam objectives for the list of hardware that you’re supposed to be able to recognize. You may have seen many of these already in your work as a network professional, but some may be pieces of equipment you’re not familiar with.

There are also very specific details you should know—I’m assuming those who put the exam together found these all too common in practice. These are listed in the exam objectives in section 11.1.4. For example, you need to know that plugging an analog modem in a digital jack in the wall will damage the modem, so you need to check first. Similarly, you need to understand that the length of patch cables contributes to the length of the cabling segment. That is, in a typical 100-meter maximum lobe length, to meet specifications we might need to include the 10-meter length of patch cable—meaning that the maximum length of cable that can be layed in this case is actually 90m, not the 100m length that we assume can be used.

A Promising Pursuit

I’ve taken a number of certification exams and found that this was probably among the most practical and useful. The emphasis isn’t on memorizing meaningless details but in ensuring you really have a practical understanding of the material and can actually do the job.

Here are three tips for taking this exam. Follow them and you’ll pass with flying colors:

• Focus on the exam objectives. Not only will this guide you through your preparation and ensure you have everything covered, but—as we’ve seen already—they prescribe the methods to use to solve problems within the exam.
• You will need to be very conversant with TCP/IP configuration and troubleshooting to pass this exam.
• Don’t try to just memorize this stuff—ensure you really understand the content. Much of it you’ll come across regularly in your day-to-day work. Get plenty of hands-on experience where appropriate. (Some of the better study guides have practice exercises to ensure you’re familiar with the material.)

Industry certification that cuts across the technologies of multiple vendors is still in its infancy. Yet, if this is a guide, it offers us the promise of valuable product-independent certification that will be of great use for employers and participants alike. Good luck!