BGP Route Reflectors

ccie r/s ccnp r/s Aug 15, 2017

A BGP-speaking router, by default, will not advertise an Internal BGP (iBGP) route to an iBGP neighbor. One solution for this issue is to create a full mesh of neighborships within an Autonomous System (AS). However, that approach doesn’t scale well.

A more scalable solution is to use a BGP Route Reflector. That’s the focus of this new video I created for you. You’ll see the issue BGP has with iBGP-learned routes and how to overcome that issue with a BGP Route Reflector configuration.

Enjoy the video!


Kevin Wallace, CCIEx2 (R/S and Collaboration) #7945

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The 3 Biggest Mistakes I've Made In My Career

career success Aug 08, 2017

We’ve all heard the saying, “Hindsight is 20/20.” However, a lack of clairvoyance about the future shouldn’t prevent us from boldly taking our next career step.

Steve Jobs told us, “You can't connect the dots looking forward; you can only connect them looking backwards. So you have to trust that the dots will somehow connect in your future.”

Looking back on the dots of my career (thus far), I feel blessed that they have connected as they have. Of course, I made (and learned from) many mistakes along the way. In this blog post, I want to share three of my biggest mistakes in the hopes that my cautionary tale will help you avoid similar missteps.

Mistake #1: Not Getting Experience Early

I attended the University of Kentucky and earned my Bachelor of Science in Electrical Engineering (BSEE) degree. As I went through my college career, my assumption was that after earning my degree I would have my pick from...

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[NEW VIDEO] Replay of my Cisco Live US 2017 Presentation

Uncategorized Aug 01, 2017

In June of 2017, I had the honor of presenting at CiscoLive for the first time. It was a great experience, and I thought you might enjoy checking it out. The session is on a Collaboration topic and is entitled Number Globalization and Localization for CCIE Collaboration Candidates. However, please don't let CCIE in the title keep you from watching if you don't happen to be at that level yet. Anyone studying the Collaboration track (at any level) can benefit from the presentation.

The amazing thing about the CiscoLive site is that you can watch previous presentations for free. You just need to setup a free account if you don't already have one.

Just visit my session's page by clicking HERE, and then click Session Video.

I hope you enjoy the session!

Kevin Wallace, CCIEx2 (R/S and Collaboration) #7945

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An Overview of Container Technology for Cisco Networking Professionals

Uncategorized Jul 25, 2017

Cisco recently introduced their Catalyst 9000 Series switches. One unique feature of these switches is their ability to support containers. This podcast episode explains the concept of containers and how they can be more efficient that virtual machines (VMs).

This podcast episode is from The Broadcast Storm podcast. Following are the links you can use to subscribe to the podcast, so you don't miss an episode:

Subscribe via iTunes:

Subscribe to RSS Feed:


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How Do You Detect Malicious Packets If They're Encrypted?

Uncategorized Jul 11, 2017

Malware poses an increasing threat to network devices. Recently, malware has been used to install ransomware on computers, which encrypts data on the computers' hard drives and demands money for the data to be decrypted (essentially holding a computer’s data hostage and demanding a ransom). A logical response to help mitigate such threats is to have a network-based device analyze traffic flows for those offending packets.

However, what if the malware concealed itself to avoid detection? For example, some malware uses TLS-based encryption (where TLS stands for Transport Layer Security), thus preventing traditional network-based threat scanners from inspecting it. Interestingly, malware’s use of TLS-based encryption is growing rapidly. Consider that in August 2015, only 2.21 percent of malware attacks used TLS, while the percentage of malware attacks using TLS in May 2017 had grown to 21.44 percent.

This increasing threat begs the question, “How do we protected...

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How "Deep Work" Can Advance Your IT Career

career success Jun 27, 2017

Recently, I bought the book Deep Work, by Cal Newport. The book gives us a strategy for becoming much more productive. In hopes that you’ll read the book too and really apply it in your work, let me tell you about a time I implemented what it teaches.

As part of my Network Programmability Fundamentals video course (which comes out in October 2017), I was trying to figure out a chunk of Python code that came from the Cisco DevNet site. The struggle was real for me every time I spent a few minutes trying to figure out what some of the lines of code were doing, and how everything worked together. So, I decided to use what I’d been reading about in Deep Work. First, let me give you an overview of the book. Then, I share with you how I used it.

Overview of Deep Work

The author begins by pointing out how in today’s technological world, we have many interruptions. Think about your day. Your sitting at your desk, and you receive a text or an e-mail that interrupts your...

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What is Cisco Spark?

You might be hearing the term Cisco Spark used a lot these days. But what exactly is it?

That's what you'll learn in this video. Enjoy!


Kevin Wallace, CCIEx2 (R/S and Collaboration) #7945

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The Siren Call of Brain Dumps

career success Jun 06, 2017

Back in my high school days, I took a class in mythology, and one of the stories that really stands out to me is the story of the Sirens. These Sirens were alluring creatures, with amazing voices, and they made beautiful music. They lived on islands, and they would sing out to sailors sailing pass their islands. Upon seeing the beauty of the Sirens and hearing their music, the sailors would steer their ships toward the islands, only to have their ships destroyed by the rocks surrounding the islands.

Today, we use the term Siren call to refer to something that looks appealing but is actually dangerous, and I think that is a great description of brain dumps. You’ve probably heard of these brain dumps, where people take an exam and post online the exact questions they saw on the exam. However, it’s not just individuals posting these questions from their short term memory, there are also companies with collections of actual exam questions that they sell on the Internet....

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The 3 Topics You Need To Know For Your CCNA R/S Exam

ccna r/s May 23, 2017

Studying for your CCNA R/S (200-125) exam? If so, a perusal of the exam topics list can be daunting. Clearly, you’re going to spend a significant amount of time getting at least a passing familiarity with the myriad of topics. However, your focus should not be spread evenly over all topics. Rather, there are some topics that need a disproportionately large amount of study.

That’s the focus of this blog post, identifying 3 of the topics likely to appear multiple times on your 200-125 exam. These topics won’t come as any surprise, but I hope this will be a reminder to expend that extra measure of effort when reviewing “the big 3.” Let’s check out the list:

1. IP Addressing

To be prepared for IP addressing questions on the CCNA R/S exam, you need several skills, including:

  • Knowing how to convert between dotted decimal notation (e.g. and slash notation (e.g. /24) for subnet masks.
  • Determining the number of useable IPv4 addresses in a...
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What is a "Leaf-and-Spine" Data Center Topology

career success May 09, 2017

For decades, we’ve heard about Cisco’s three-tier network design where we had the following layers: (1) Access, (2) Distribution, and (3) Core. The Access Layer connected to our end devices (e.g. clients and servers). The Distribution Layer redundantly interconnected Access Layer switches, and provided redundant connections to the campus backbone (i.e. the Core Layer). The Core Layer then provided very fast transport between Distribution Layer switches.

However, within today’s data centers, a new topological design has taken over. It’s called a Leaf-and-Spine topology, and in this short blog post, you’re going to learn the basics of how it’s structured.

Imagine a cabinet in a data center, filled with servers. Frequently, there will be a couple of switches at the top of each rack, and, for redundancy, each server in the rack has a connection to both of those switches. You might have heard the term top-of-rack (ToR) used to refer to...

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