Jeff Rensink

Author Archives: Jeff Rensink

Preparing for the CCIE Wireless v3 Diagnostic Section

I had the pleasure of attending the CCIE Wireless tectorial at Cisco Live in San Diego this year. One of the topics discussed was the new diagnostic section of the lab. Jerome Henry gave us insights into what the section would look like as well as some examples of the types of things that we can expect in the section. I wanted to pass on some of that information along with a few insights about how you should prepare for this section since it’s quite different than what we’ve seen before in the lab.

What is the Diagnostic section?

Starting in v3 of the wireless lab, each lab will begin with a 1-hour diagnostic section. This section has no configuration task associated with it. Instead, you will be playing the role of TAC, or a senior level engineer. Your job is to look at information gathered from a client by a first-level engineer and analyze it so that you can answer questions related to troubleshooting an issue.

It sounds like you can expect maybe 3-4 separate troubleshooting scenarios with approximately 10 questions to answer across those 3-4 scenarios. So that means there will probably be 2-4 questions per scenario. All Continue reading

Building a CCIE Wireless v3 Home Lab on the “Cheap”

With the new version of the CCIE Wireless lab coming in September, many people will be looking to start preparing for their lab attempts. But one look at the hardware list for the exam shows that fully replicating the lab will be out of reach for just about everyone, unless your work already has a spectacular lab. But as with most every track, you can typically practice most things on a home lab without breaking the bank if you look at alternative options.

Before I list out my recommendations for a home lab, know that it will have some significant limitations. It’s not something that you could become fully lab ready on. Also, you will have a hard time following along with the workbooks that I’ll be putting out due to the restricted number of devices and the restricted feature sets available to them. But for self-directed study, this will allow you to practice a large portion of the v3 blueprint.

Recommended Hardware

These recommendations assume that you are starting a lab from scratch and don’t have existing equipment to pull from. If you have better stuff than what I recommend, use them.


You will probably want to use Continue reading

How to use AnyConnect to “cheat” in the CCIE wireless lab

How would you like to be able to look up the answers to some of the tasks in the wireless lab, and not get in trouble over it? Well, read on, and I’ll give you a fun tip that you may be able to use in the lab to solve parts of certain lab tasks. It’s not actually cheating, but it almost feels like it.

One of the realities of the lab is that there will be some pre-configurations on many of the devices. You won’t be configuring every last device from scratch. There’s not enough time, and they’d prefer to test you on more complex things than configuring every VLAN, interface, host name, etc from scratch. Just about anything has the potential to have some level of pre-configuration, and that includes the AnyConnect client. If you find that the AnyConnect client already has some WLAN profiles configured on it, say a silent “thank you” to Cisco because they just gave you a ton of great information.

Another reality of the lab is that they often don’t ask you to do things in the most straightforward and clear way possible. Often they use code words or phrases that need to Continue reading

Cisco Announces Version 3 of the CCIE Wireless Blueprint

The wait is finally over and version 3 of the wireless CCIE blueprint has finally been announced.  On September 14, the new version of the written and lab exams will go live.  This will bring a very long-in-the-tooth version 2 blueprint to an end after a nearly 4-year run.  While we tearfully say goodbye to WCS, let’s take a look at what version 3 is bringing to the table.

New Lab Exam Format

First off, let’s look at what has changed in the format of the lab itself.  The wireless track is following suit with the R&S and SP tracks and including multiple sections to the lab.  The wireless lab will now begin with a 1 hour Diagnostic section, followed by a 7 hour Configuration section.

The Diagnostic section is similar to what was done in R&S and SP.  This section tests your ability to assess and diagnose issues in a network without any access to the devices themselves.  Basically, you are given access to a number of pieces of information (emails, topology diagrams, logs, etc) that describe an issue and give the needed information to figure out the root cause.  You Continue reading

Why joining APs to a Controller Across a NAT Needs Special Configurations

Many wireless engineers know that having a lightweight AP join up to a controller across a NAT requires some extra configuration. But many don’t understand why it needs the configuration. This article will talk about what the NAT is, why it causes a problem for the normal join process, and what the configuration changes do to make things work.

What is NAT and where do we see it in the wireless world?

NAT stands for Network Address Translation, and it does pretty much what the name implies. It translates addresses from their original values to something new. Let’s take a look at a classic wireless example.

Let’s say I have an office Extend AP (OEAP) in my house, and I want it to join the WLC in my company’s DMZ. But I don’t want to actually configure a public IP on my WLC. This is where the NAT comes into play.

Screen Shot 2015-03-13 at 12.12.16 PM

In the image above, the OEAP talks through the firewall in order to talk to the DMZ WLC. In order for the AP to talk to the WLC, it has to target a public IP because it needs to communicate across the Internet. So if the WLC itself doesn’t Continue reading

Wireless Configuration Method Speed Test Shootout :: Part 3

This is the third and final article in a series focusing on seeing which configuration methods are fastest or slowest in the CCIE wireless lab.  The idea is to test each method under a variety of likely configuration scenarios that you would experience in the real lab and see how things stack up.

Check out the supporting Speed Test video playlist on our YouTube channel.

This article focuses on autonomous APs.  I set up 3 different scenarios, as listed below:

  • Configuring WDS using local RADIUS and registering 2 APs
  • Configuring two SSIDs with their associated VLANs
  • Configuring a few settings under the radios

If you want to watch the actual configurations, you can check out the companion video to this article over in our YouTube channel.  It shows how I arrived at the configuration speeds and the methods that I used.  You may be able to pick up a few tips or tricks for faster configurations by watching how I do things.


For this test, had to configure local RADIUS with a network device and user account, then configure AAP1 as a WDS with associated authentication methods.  Finally, I registered both AAP1 and AAP2 Continue reading