Narrowing Your Router Search Based on IOS Version

 In 200-301 V1 CCC No Category on Purpose, CCENT-OLD, LabGear

Turn your #CCENT and #CCNA home lab search upside down for today’s post. Instead of thinking “I need routers”, think about routers as simply a place to run router IOS. Then, think about what router IOS version you want to run in your lab. The routers are just a place where you can run instances of Cisco IOS software for routers.

Today, I’ll explore routers for your home lab, but focus on the IOS version. I’ll list some of the common routers used in home labs, the latest IOS mainline or T-train version supported, along with Wendell’s opinion of where you want to be with the IOS version.

Earlier posts in this series:

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Breakdown: Best IOS Version for Common Used Routers

As someone new to Cisco, a typical CCNA candidate cannot possibly understand all the router model series, and specific router models, in Cisco’s long history. If you look long enough, you can find routers for sale online that Cisco quit actively selling 20 years ago or longer. These routers still power on, still run IOS, and can still be used to learn about some CCENT and CCNA topics. So, it’s hard to just search a site with “Cisco router” and sift through the detail to find the right router.

When Cisco quits supporting an old router model, Cisco simply no longer compiles IOS images for that router model. So, there is a literal IOS version that is the most recent IOS version that can be used on that router. From an exam prep perspective, that IOS is the best IOS to have, because the more recent the IOS, the more new features supported.

Figure 1 shows some of the numbers of the more popularly used router models for Cisco home labs, plus the most recent IOS version supported on that router.

Figure 1: Common Used Router Models and Most Recent IOS



If you just look at Figure 1, and had no other constraints, then using the routers at the bottom, with the most recent IOS possible, would be the best choice. But you always have to introduce reality to the decision, and pricing of course is a big part of that reality.

My co-worker Chris is working hard at collecting some real data to update my price estimates for my web site. In the near future, I’ll have some updates on those prices. For now, I’ll use some general estimates to give us a general idea of prices when thinking through whether you would spend a little more to get a little better IOS version.

For the sake of discussion, I have created a price estimate for a router in each of four categories: ancient, really old, old, and not-that-old. Just like the prices posted at, the price is for a router with one Ethernet plus two serial interfaces. For example, if a router has built-in LAN and WAN interfaces, nothing is added, but for a router that has 1 LAN interface but no WAN interfaces, price estimate includes a serial WIC-2T.

Figure 2: VERY General Price Estimate Just for Comparison Purposes

Now image that, after reading the first post in this series, you expected to buy three routers. Have you already blown your budget even with the ancient routers? Could you possibly afford the not-so-old? Those questions are important. However, today’s post focuses on one other important question:

What better IOS version could I get with a more recent/better router?


Wendell’s Opinion: Try to Afford a Platform for at Least 12.4T

In the previous post, I worked through some of the issues surrounding whether you needed IOS 15.something, or not. Personally, I think IOS 15.something is nice, but not a requirement. For perspective, say my general price estimates happen to be perfect. So, you could get:

  • Old routers, running 12.4T, for $100 each or $300 for the trio
  • Not-so-old routers, running 15.1M, for $150 each or $450 for the trio

Which would you choose? Some would choose the first option, some the second, and some frankly would look at cheaper options, and that’s ok. Point is, that’s $150 difference to get from 12.4T to 15.1M. And what do you get? Not much. (I’ll get to more detail once I get the web page updates done, and post more in the coming weeks.) However, on the routers in the figures, with 15.1M instead of 12.4T:

You do get: More current syntax and output in show commands, including the better “show ip route” output with local routes.

You do NOT get: IOS licensing support, because while IOS 15 supports IOS licensing, it’s only on some platforms, which does not include these not-so-old models.

What would be nice is a list of features required for CCENT and CCNA, and what’s supported at each version. And guess what – I’m working on updating exactly those lists at my web site! Next post will begin to refer to those updated pages.

Wendell’s Opinion

All the options to build a home lab have some benefit to helping you learn. Even using the “ancient” routers helps: even some ancient 2501 routers (1 Ethernet, 2 serial) will let you configure IPv4, OSPF, EIGRP, ACLs, NAT, much of IPv6, and troubleshooting. Certainly the newest routers listed here are great to have, but they just cost more.

Given past experience, I think the routers that support a best IOS of 12.4T will end up as the best compromise, at least until the not-so-old routers (870, 1800, 2800) drop in price. In the mean time, figure 3 summarizes my opinion about these four general categories:

Figure 3: Wendell’s Opinion on Router Categories and IOS Versions


If you are working through this post real-time, start thinking in terms of buying an IOS version as much as a router model. The router model enables the interfaces possible, and the IOS versions possible, but the IOS version more directly dictates what features you can configure and test. Pick one or two of the categories from figure 1, where you will most likely sit when it comes time to spend money. Start getting a feel for finding the IOS version installed per the product as listed, interfaces included, and so on.


IOS Version 15 for a Cisco Home Lab – or Not
#CCNA Home Lab Homework: Cisco Feature Navigator
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Adam Steele

I have 1x 2651XM and 2x 2621XM routers in my home lab all running 12.4T and they are fantastic! Great bang for your buck!

I just purchased an AS2511 and am seeking a 3560 switch at a decent price but they are tough to find in Canada.

Matthew Simpson

Mr. Odom,

In regards to purchasing used routers, is there any way one can download the most up to date version of a Cisco IOS for their used router? I don’t think there is currently any sort of option to get an updated IOS. I’ve looked at several 2600xm version routers and they all were running 12.2 or 12.3 IOS according to what the seller was posting about them. Even though the 1841 can run the 15.1 IOS many I have seen run the 12.x IOS.


Matthew Simpson


Hi Matthew,
By the way, thanks for the Mr., but feel free to call me Wendell. 🙂
Well, once upon a time – from literally the creation of web technology and Cisco’s first web site, until maybe 3-4 years ago, anyone could download any IOS image for any release. It was all on an honor system that you paid for what you used. Not so any more. Now, Cisco does various checks at their web page, and if your account isn’t linked to a service contract for that model of routers, the IOS download is generally rejected. So, to get a more recent IOS image, even if your box supports it, requires:
– a service contract
– Google searches to find an image someone as (illegally) posted

Realistically, it’s a purchase-time decision when buying used gear… which is why I spend so much time (relatively) of the lab discussion talking about IOS choices. So, seeing an 1841 with say 12.4 mainline is great, but taking your time to look for one with at least 15.0 is better.


Does it matter which 15.X version IOS I get when I purchase a router

I see 15.1 and 15.1t on Ebay ???


It matters some. As always, check out Cisco Feature Navigator. However, for the big picture…
Cisco has several release “trains” for IOS software. Think of a lot of trains in the trainyard. Some go one direction, some another, to different destinations. Each train has many train cars, of course. So, in Cisco-speak, Cisco takes a code base, and starts a train – the M train, T train, and so on. They head in different directions for different purposes – M train with mainly bug fixes only, making it more stable, and T-train with some new features added, which also risks introducing more bugs. So, in general, a T-train release with the same version and release number has at least the same features as the equivalent M-train release, and often more. That’s the general idea. Other trains may introduce even more specialized features, adding different kinds of risk.
It can be a black hole to research it all for your home lab – that’s why I tend to research the M train only, just to simplify the process. But you can always go back to check the feature navigator for a given version.


As of 2013 on you can find 2811s and 2821s for about the same price reflection as a 2611xm or better. I was able to get a 2811 for $75 and a few 2821s for $100 – 120 each.


Hi Rashiem,
Yep, we’ve been looking at 2801’s for about 6 weeks, to find what normal pricing looks like, and it’s pretty good. (Can’t check every model!) Thanks for the input!



I am a newb to Cisco and am pursuing my CCENT currently. I have your cert guide and am trying to build a lab that will allow me to grow to NP and possibly IE. I am a bit unsettled though regarding Cisco licensing, and was wondering if you could expound a bit. I purchased 2 3550 PWR (legit EMI) switches and 3 2821’s with a 16a for an access server. My head is spinning regarding the licensing for these things. I saw some sellers online selling SMI devices with EMI images, which threw some flags and caused me to check into the licensing initially. Now I am finding out on Cisco’s site that I potentially have to have my equipment inspected and pay license fees. Is this what they expect for home labs? Also, is there a way to find out what image I should be running on them? I want to please God in this and not steal from Cisco in any way, shape, or form, however, if they want me to jump through these types of hoops and hand out an extra good chunk of change to be square with them, I might have to choose a different career path, as I cant use stuff illegally in good conscience, and I dont have deep pockets. Thanks for your time.


Hi David,
On your specific questions…
For a home lab, I personally have never heard of Cisco attempting to enforce the licensing, requiring someone to pay for licenses for used devices. And that’s part of the problem: there’s the legal perspective, and what you can literally do, and the ethical perspective of whether or not you should do it. And then there’s the whole world of what people do – I believe the vast majority of those studying just google to find IOS images and use them. In a word, it’s a mess.

Where you personally end up on all this does have a lot to do with how you view the world. And if you end up literally following all rules, it’s expensive. However, there is hope in site!

Cisco has publicly announced a new product called Cisco Modeling Lab (CML), which was formerly known as Virtual Internet Routing Lab (VIRL). You can find a few articles about it on the net. Short version: legally per Cisco, run virtual OS images for all their device OSs – router IOS, switch IOS, Nexus, etc. Cisco hasn’t announced pricing yet, or performance, but I’m guessing that for less than $1000 for a server with lots of memory, you’d be able to run lab pods for most anything through CCIE R/S. Beautiful idea. I’d suggest it’s probably worth waiting to see how that plays out before totally abandoning the Cisco cert idea.


Thanks for the quick response. I called Cisco today and got to their licensing department, after about 4 hops. They are all very nice to work with, however, nobody seems to have ever dealt with this before. I am working with someone there to determine what they will do. It really does stun me a bit to see such a large, successful company, have such a blind spot in a very important area like this. I would think they would have a student or home lab policy where you can download ios’s etc for end of life equipment, encouraging people who are pursuing certs to support their equipment. ~Baffled~ At a 30k foot view, it seems like you said, cert seekers generally don’t care, and Cisco doesn’t enforce. Thanks again for your help, and I will let you know what I find at the end of this road.


Sure thing, David. I’d be interested if you make progress. But the overarching story is a looong one – for home study, it’s definitely been a case where Cisco basically ignores enforcing the licensing for study purposes.


Hello sir, I called Cisco two times. First time around, no dice. The second time around, I called TAC first, then went to Licensing, then finally sent to Certifications. They contacted some of their resources and were able to give me an answer. In short -on to labbing with the IOS’s that came with the devices, however, if I need upgrades to my IOS’s, I will have to purchase them. Thanks again for your time and your responses.

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