CCNA Lab III: Sifting Through the Router Model Series

Going from Nothing to Getting in the Right Ballpark

If you go to EBay, and search on "Cisco router", you get a lot of hits (over 7000 just a few minutes ago.) It can be quite daunting if you're early into your CCENT or CCNA study, three chapters into the ICND1 book, and trying to figure out what router to buy. You don't want to spend all your time learning the entire Cisco product line, but you don't want to waste your money. In today's post, I'll start the process of sifting through what you have to think about by looking at the big picture: finding router models that are old enough so that the used prices are low, but new enough so they are still useful for studying.

As a brief reminder, we're making some assumptions in this series. First, you, or someone you know, has decided to go for CCNA. You want to use real gear instead of the other options. I'm assuming that you are at least thinking about buying this stuff on auction sites, rather than asking one company to just sell you the whole package. (It's reasonable to buy from resellers, but you'd probably start by asking them for recommendations, rather than reading through this series.)  And I'm assuming that you already read the other links in this post (see links at the end of the post, or just look at nww.com/odom.)

Also, note that I'm purposefully focusing on the basics here, assuming you really are in that first week or two of CCENT/CCNA study. Those of you who've been there/done that, jump in here and tell us your thoughts related to what you wish you'd known when you first started buying gear.

The Big Picture

I could start by just telling you to buy 3 or 4 2501's, max RAM and Flash, a few serial cables, a few Ethernet transceivers, and a few Ethernet cables. And you know what? You could learn a lot of the CCNA topics just with those routers. And even if you later decided that you wish you'd bought something else, and you end up replacing those routers, well, guess what: you'll probably still be using those 2501's occasionally 3-4 years from now, assuming you're still pursuing Cisco certs.

On the other hand, as soon as I made that bold pronouncement, you'd see some comment from someone else, saying that they'd rather get a 2610. Or a 3640. Or a 1721. Or you read comments on the Cisco Learning Network telling you not get get those old 2501s. Or worse yet, you might read about what some people bought, but they don't say why. Or, you talk to a company that sells packages of gear for CCNA study, and they're offering some different model. Now what?

There is no one answer. The choices are a bit messy. But at some point, you need to choose, buy some gear. So, what's a reasonable goal? If you can go from knowing nothing about Cisco routers, and buy a lab with which you can do 75-90% of what you need to practice for CCNA, that's a great start. If you can get 100% of what you need, fantastic.

Cisco Router History

Oh boy, a history lesson! Well, I'll make it brief at least. The goal: give you some context to figure out what you read about Cisco routers.

Cisco has created lots of specific models of router over its 25 years or so of existence. Often times, they create a model series, with the routers having some major similarities, and some smaller differences. For example, back in the early 1990s, Cisco created the 2500 series. All the specific models of routers started with "25", with two digits other than "00" to designated the specific model. One popular model from that series, which we'll talk about a few times in this series, is the 2501: a router with 2 serial interfaces, 1 Ethernet AUI interface, and no expansion slots. For perspective, the 2502 router was the same thing, but with 1 Token Ring LAN interface instead of Ethernet. Another model had both Ethernet and Token Ring, some had more serial interfaces, and so on.

When first learning to sift through the options, the first thing to do is to figure out the model series that are old enough to be cheap in the used markets, but new enough to be useful for study. To do that, we'll make some generalizations. Of course, the instant you generalize, exceptions start showing up, but you have to start getting your head around this idea somewhere. So in Today's post, I'll give a broad brush description of the series, and list a couple of models that are likely good candidates these days.

2500's

These things are old. They were old 10 years ago. So, are they too old? Well, did I tell you that they're cheap? And they're not too old. You can do maybe 75% of the router features for CCNA on 2500s. And they're cheap. If you're on a tight budget, but still want real gear, and say $20-30 per router matters to you, then it's worth a hard look.

As for models, you just look for the ones with an Ethernet interface. Most come with two serial interfaces. As long as the 2500 comes with 2 serial and 1 Ethernet, you can use them to create all the topologies we discussed last post, except that one four-router topo that is really only needed to test one particular feature of OSPF.

Quick hits:

  • The oldest reasonable option.
  • Typically fixed interfaces, i.e., you buy the router, no expansion slots, and no interface cards to remove/replace.
  • The most recent IOS version is 12.2 mainline (more on that in a later post)
  • No 802.1Q, period
  • Cheap!!!!

2600's - Non-XM and XM

Once the 2500 series started to age a bit, Cisco (somewhere in the mid-to-late 1990s) introduced the 1600, 2600, and 3600 series. Let's focus first on the 2600 series.

First, today, the 2600s actually fit into two different mode series. Initially, Cisco came out with a model series called 2600s. Then, Cisco improved the hardware enough to matter for real networks, and instead of doing something clever, like creating a new model series 2700s or something, Cisco called the new routers 2600XM. Both series are old and not sold any more as new by Cisco today.

Cisco billed these more for medium size remote offices, or WAN edge routers for central sites for medium sized companies. That is, not the biggest/fastest routers, but not the smallest/slowest/cheapest Enterprise routers, either. However, comparing non-XM and XM, the XM routers indeed had better performance in production networks when the load was higher, which doesn't matter for learning CCNA today. The XMs also had 10/100 Fast Ethernet interfaces generally, rather than the non-XMs generally having 10 Mbps Ethernet. Finally, because the XMs came out later, and Cisco quit selling non-XMs as new years before they did the same with the XM models. For us today, that means that the XMs generally support better IOS versions.

Like most modern routers sold as Enterprise routers (rather than consumer routers), the non-XM and XM 2600s are modular. That is, they have card slots similar in concept to a PC's expansion slots. These slots support cards that have interfaces connected to them, e.g., the WIC-2T card has 2 serial interfaces that you can use to create point-to-point WAN links or Frame Relay links. Most of the 2600s (both flavors) have 1 or 2 built-in Ethernet interfaces, and other slots for small interface cards ("WIC" slots) and slots for larger cards called "Network Modules".

Quick hits: non-XM

  • 1 generation newer than 2500s
  • Better IOS (12.3 mainline)
  • modular
  • Can support 802.1Q with the right IOS version

Quick hits: XM

  • 1 Generation better than non-XMs
  • Better IOS (12.4T)
  • modular
  • FastEthernet interfaces, with 802.1Q trunking

1700s

While the 2600s were more for a robust branch office, Cisco sold the 1600 series routers for small branches and remote sites. Over time, to offer a better performing option, Cisco introduced similar but faster routers called... 1600XMs. Not really. In this case, Cisco made the 1700 series. (OK, older/more experienced folks, throw in your own recollection here, but that's how I remember it...)

Both series - the original 1600 series, and later the 1700 series, were meant more for small branch offices. These routers usually had 1 LAN interface, and a WIC slot to add some WAN connection, like a single or dual serial link (WIC-1T or WIC-2T, for instance).

For a lab, you typically don't care if the router can forward 20 zillion packets per second (pps) or not. What you care about is whether you can configure the same commands, see the same show command output, etc. So, these routers meant for smaller sites still work fine.

As a practical matter, for labs with old used gear, I've pretty much ignored the 1600s. But the 1700 series includes several models that support all the right stuff, and are somewhat cheap. Some 1700s use the same 19" wide form factor for easy addition to a rack, but others have to be placed on a shelf. They're modular, just with fewer slots available than the larger 2600 models. Most 1700s come with Fast Ethernet as a built-in interface, with the slots used for WICs.

Quick hits, 1700s:

  • Similar age to 2600XMs
  • Good IOS support (12.4T)
  • Great price vs feature support tradeoff today
  • FastE with 802.1Q

3640s

So, 1600/1700s for smaller branches, 2600/2600XM for larger branches, so the 3600 series must have been much beefier, and they were. Literally bigger - from having 2 Network Module (NM) slots in the 3620, to the 4 NM slot 3640, and the 6 NM slot 3660, you get everything you'd expect on the larger/faster/more expensive series.

As with all these model series, Cisco does not announce one day that the entire model series is no longer sold as new (called the End of Sales, or EOS, date). They announce EOS for some of the models in the series, then others. Sometimes Cisco keeps adding new models to the same series, which really messes up newbies that look at 20 years worth of old EOS models in the used router market.

Cisco happened to keep a few 3600 series models around, delaying the EOS for those models, which results in some help for us - the 3640 in particular. Cisco supports a relatively recent IOS (12.4 mainline) on this router. And oddly enough, it can be somewhat cheap in the used market, although you should keep an eye out for the shipping cost, since these things do weigh more than the others.

So, what do you get? The router itself includes no interfaces at all; just NM slots. So, to even have an Ethernet interface, you need a NM that has some form of Ethernet on it. And an NM that supports slots to add WIC cards. End of the day, though, it's still a somewhat reasonable cost for these once you add all the cards.

Quick hits:

  • Bigger
  • Reasonably good IOS (12.4)
  • Takes a little more knowledge to buy (NMs)
  • Supports some features others don't that could help for CCNP

800s

Many of the other router model series listed above were created in a world for which WAN connectivity meant serial links. Those were either point-to-point, or Frame Relay, and on rarer occasion, ATM. At the same time, by the mid to late 1990s, people considered Internet VPNs as a reasonable alternative.

The Cisco 800 series essentially created a lower-end router for remote Enterprise sites, but with some of the same features you see in consumer routers today. Most do not even support a serial link. Instead, they have cable modems, DSL, or Ethernet interfaces to be used as WAN connections to external cable/DSL modems. They often include hardware to accelerate VPN connections. In some cases, they include integrated LAN switches, to provide a small number on LAN ports for a small remote site.

These routers, as Enterprise-class routers, still run the same old IOS, which is good for study purposes. But most models do not have serial interfaces. They can be part of a reasonable overall strategy for what to put in your lab.

Finally, the 800 series has had a long history. It's hard to tell which models are still sold, which are a little old, and which are really old.

Quick hits:

  • Most have LAN interfaces only
  • Often have VPN hardware
  • Good old IOS
  • IOS support varies on model, but can be 12.4 or 12.4T
Related Posts:

CCNA Lab Series 2011: Overview

CCNA Lab II: How Topologies Drive Device Choices

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