Exam Network+ (NK-N10-001) Vendor CompTIA Status Live (Note: Beta version was reviewed for this article.) Reviewer's Rating "You still need to know your stuff, but this is a very practical exam on network fundamentals." Test Information 65 questions, 90 minute time limit, $185. Who Should Take This Exam? Anyone interested in obtaining a non-vendor networking certification. Some vendors, such as Novell, accept the exam in place of other vendor-specific tests. What Classes Prepare You? No CompTIA classes available, but various training centers and programs offer their own classes. Test Objectives URL www.comptia.org/ certification/networkplus/ objectives.asp

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, including:

• addressing
• subnetting
• standard ports
• configuration
• standard applications
• troubleshooting tools

The good news is that unlike Novell's comparable Network Technologies exam (part of the company's CNE program, which can now be replaced by this exam), you don't have to know hundreds of obscure acronyms. In this article I'll highlight the main areas you need to master in your preparation for the Network+ test.

Knowledge of Networking Technology
How well do you understand each of the seven layers of the OSI Reference model, and what each 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.

Test Tip: Layers As well as these layers, a network professional should understand the different 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.

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

• 802.2--Logical Link Control (LLC): 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

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. See Table 1 for details.

Table 1: TCP/IP Address Ranges Address Class Address Range for First Octet Subnet Mask A 0 - 127 255.0.0.0 B 128 - 191 255.255.0.0 C 192 - 239 255.255.255.0

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.

Table 2: Ports Used by TCP/IP Apps Port # Application Name 20 FTP (data) 21 FTP 23 Telnet 25 SMTP 80 HTTP 110 POP3

Given the practical nature of the exam, you also need to understand how you actually configure TCP/IP on a client as well as 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);
• 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; and,
• 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 adapter and the network IPX address.

Test Tip: PING 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.

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 objectives include an understanding of star, bus, 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.

Test Tip: Hardware 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.

Use this approach in the exam when asked which problem-solving step should come next in the situation presented.

There are also very specific details that the exam wants you to 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 maximum length of cable that can be laid 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 more 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.
• TCP/IP is key: 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 some useful product-independent certification that will be of great use for employers and participants alike. Good luck!

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