CCNA Lab Part 7: Choosing the Right Switch Models

Moving on From the Router Discussions

After working through a longish discussion about Cisco routers for your CCNA lab, it will be nice to discuss switches. Thankfully, the choice of switches is a lot easier to figure out than the choice of routers.  Switches have less software clutter to sift through, and the used prices for the likely candidates converge down to two families: 2900XM and 2950. Today I'll give you a big picture look at these families, enough so that you can make sense of what you see when searching for these products on used gear auction sites. Also, I'll make a quick public service announcement for a Cisco virtual event about certifications that applies to newbies and oldies.

Quick Link and Announcement:

Cisco is hosting an online Talent Development Fair. It looks like about a 6 hour event, Thursday, June 23rd, starting at 8:30 Pacific time. FREE, but you have to register. If you've read this far into my post, then you're close enough to the audience to be worth a click and a read of this page.

Now, on to our show!

Brief Historical Perspectives on CCNA

Before looking at the 2900XL and 2950 series, first let's consider a few short historical perspectives. Any time you're considering buying used gear, some of which may be over 10 years old, it helps to think about some of the history.

First, Cisco doesn't tell us what model of hardware to use, either for routers or switches. They assess our knowledge and skills of router and switch features. But, over time, software changes, and Cisco adds and removes model series from what they offer to sell, so some changes indirectly impact what we ought to study.

Focusing on routers for a moment, most of the change over time, relative to CCNA, has occurred with command output. Cisco might update or add info in the output of a command, or change a keyword, or change the syntax of the command. So, if you look at CCNA's history from 1998 until now, the hardware has changed, but those changes have not really changed the details of what Cisco asks us on the tests. The software changes have subtly changed the details of what they test, which is one reason why I spent so much time talking about router IOS in earlier posts in this series.

Focusing on switches, both the hardware and software have changed, but two factors mean that those changes have had a bigger impact on CCNA. First, when CCNA started in 1998, switches varied quite a bit in command syntax and output. For instance, all switches supported 802.1d Spanning Tree, but they might use different commands, with different output, to display the current status. Those commands and output have converged to be much more consistent today. Plus, switch hardware has changed quite a bit as well.

So what does this mean to a newbie to CCENT or CCNA? Well, officially, you should be able to get any Cisco switch and learn from it, and learn things useful for CCENT and CCNA. I agree. But if you're spending the $, let's get the best match for today's CCNA exam. To that end, let's first discuss what not to buy (in my opinion, at least).

What not to Buy: Linksys

Cisco sells routers and switches in the consumer market under the Cisco brand today. Back a few years, Cisco bought a company called Linksys, which was already well established as a consumer networking products vendor. As you might imagine, the product line has grown and melded over the years since that acquisition, but the short version is that many of us may well have a Cisco switch sitting in our house or apartment.

That's not what you need to study with for CCNA. Most of these devices have only a web interface, do not run IOS (at least outwardly), and do not have a CLI. Can you learn from playing with the features and interface on a Linksys/Cisco switch? Sure. It's just not optimal for what you would need to do for CCAN preparation.

What not to Buy: 1900s

About a million technology years ago, Cisco sold switches in the 1900 model series. (There's a router model series called 1900 today; be warned!) When Cisco first introduced CCNA in 1998, 1900 series switches were already old enough so that Cisco didn't try to sell them much, instead selling newer/better switches. However, the Cisco authorized CCNA course at the time included details about 1900 series hardware (just a little), and some details of the software specific to the 1900s, so the CCNA world sort of latched on to the 1900 series models as a good model to own. And for good reason - 1900's were already reasonably low priced in the used market, given their age, and they worked, and they matched the course books, so it made sense to buy 1900s.

Today, the differences between the command output, the command syntax, how the switches store config, etc, all tell me that you really should avoid the 1900 series switches. Some may disagree, but I think they're just too old. And if you're just trying to save $...

What to Consider: 2900XL

The 2900XL series is a set of switch models meant for wiring closets that reached End of Sale (EoS) and End of Life (EoL) in the 2001 to 2004 timeframe.  As with most switches series, the different models had different numbers of physical ports or interfaces. With this series, and unlike the newer 2950 and 2960 series, the product number changes based on the number of ports. For example, a 12-port model might be called a 2912 for short. The full product name might be WS-C2912-XL-EN, which is a model with 12 10/100 ports, and Enterprise software.

Most importantly for us, these were some of the first access switches (over time) that were more IOS-like. They were mostly similar to router IOS CLI, follow the same navigation into and out of config mode, stored the configuration with mostly the same rules, used the same help features, and so on. They were much closer to "normal" router IOS, at least compared to 1900s. So, as tools for exam prep, they are a good fit.

As for software, the only thing to watch is to make sure and get a model with Enterprise Edition software; these models end with "-EN" in the formal model numbers. That's typically not a problem in the used market. You can double check the product numbers from this document:

What to Consider: 2950 Standard Image

Cisco announced the 4th major version of CCNA in 2003, and the 5th in 2007. (Cisco doesn't put version numbers on the exams; that's just counting them.) The authorized Cisco courses that came out in 2003 used, in a few examples, the then-best access switches from Cisco: 2950. In 2007, the courses used a few examples with the then-best access switches from Cisco: 2960.

To be honest, the authorized Cisco courses had nothing that tied the material to one model series, so you could use any model with which to study. However, for perspective, think about the big picture. In the 1990s, Cisco has switches with a wide variety in command syntax and output for the same feature. Over time, the switch IOS has converged to use the same syntax and command output. If you compare some of these generations:

 But let me make a few points of comparison that matter to our choice of what to use for CCNA:

1900 to 2900XL: significant changes

2900XL to 2950: Minor changes

2950 and 2960: insignificant changes

Now, ponder those points versus our reality of wanting to buy used gear for a CCNA lab. You want to buy something that's useful, but spend as little as required. It's a balancing act between being too new, and therefore still too expensive in the used market, and too old, because it's too different from today's exam. The 2950s give you a great compromise: commands and output practically identical to the current 2960 models, but lower prices.

2950: Standard vs. Enhanced Image

As for software, the 2950s originally had two software trains: a standard image and an enhanced image. However, the model of switch dictates the image. You cannot just buy a standard image 2950, get a copy of the enhanced image software, and load it on that standard image 2950. So, when before you buy a 2950, first consider whether the switch is a standard image switch or enhanced image.

Link to a list of 2950 standard image

Link to a list of 2950 enhanced image

That said, the standard image, for CCNA, should work just fine. Finally, you might think that you want the better "enhanced" image, but for CCNA, the standard image should work fine. In fact, best I can tell, you miss nothing for CCNA with the standard image compared to the enhanced image. (Check out the feature table at my web site; as usual, all info is accurate as best I can tell, but no guarantees.)

Related Posts:

CCNA Lab Series 2011: Overview

CCNA Lab II: How Topologies Drive Device Choices

CCNA Lab III: Sifting Through the Router Model Series

CCNA Lab IV: Choosing the IOS Version and Feature Set

CCNA Lab V: Ruling Out (or In) 2500 and 2600

CCNA Lab 6: The Best Router for CCNA, 2011

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