It's Time to Pivot

Uncategorized Jan 01, 2017

One of the big buzzwords you hear surrounding tech startups is pivot, which is what happens when a company is moving in one direction and makes a strategic decision to go in another direction. For example, the company we now know as Twitter was once known as Odeo, which was going to offer a way for people to subscribe to podcasts. However, with iTunes becoming a dominate force in podcast subscriptions, the decision was made to pivot to a micro-blogging platform.

Sometimes, we need to make a pivot in our own careers based on what we anticipate happening to the industry. For example, many local bookstores have disappeared because of Blockbuster went bankrupt in their video rental business with the advent of NetFlix and streaming video services.

The electric light did not come from the continuous improvement of candles.” –Oren Harari

Let’s now consider the networking industry. Personally, I’ve been working with Cisco routers since 1989...

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Understanding EIGRP – Part 2

ccie r/s ccna r/s ccnp r/s Dec 02, 2016

In the first blog post in our Understanding EIGRP series, we were introduced to EIGRP’s features, in addition to a basic configuration example, and a collection of verification commands. Now, in this post, we’ll delve into the behind the scenes action of how EIGRP establishes a neighborship, learns a route to a network, determines what it considers to be the best route to that network, and attempts to inject that route into a router’s IP routing table.

EIGRP’s operations can be conceptually simplified into three basic steps:

Step 1. Neighbor Discovery: Through the exchange of Hello messages, EIGRP-speaking routers discover one another, compare parameters (for example, autonomous system numbers, K-values, and network addresses), and determine if they should form a neighborship.

Step 2. Topology Exchange: If neighboring EIGRP routers decide to form a neighborship, they exchange their full topology tables with each other. However, after the...

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Understanding EIGRP – Part 1

ccie r/s ccna r/s ccnp r/s Nov 18, 2016

I used to work as a Network Design Specialist at Walt Disney World, in Florida. Their massive network contained over 500 Cisco routers (and thousands of Cisco Catalyst switches). What was the routing protocol keeping all of these routers in agreement about available routes? It was Enhanced Interior Gateway Routing Protocol (EIGRP). That’s the focus of this blog post, which is the first of a series of posts focusing on EIGRP.

If you already have your CCNA R/S certification (or higher), you’re probably well acquainted with EIGRP. However, unless you have an eidetic memory (like Sheldon Cooper on The Big Bang Theory TV show), you probably don’t remember every single EIGRP command and concept. Therefore, this series of blog posts is going to review and reinforce those fundamental EIGRP concepts, and even introduce a few other fun facts.

EIGRP Fundamentals

There’s a long-running debate about the fundamental nature of EIGRP. At its essence, is EIGRP a link...

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Accessing the Cisco DevNet Sandbox

ccna collaboration Nov 11, 2016

If you’re studying for a Cisco certification, you might be debating what to do for your hands-on practice. Will you buy a home lab? What about using a simulator or an emulator?

Well, before spending any money, consider Cisco’s DevNet Sandbox. For example, let’s say you’re studying Collaboration technologies. You can (for FREE) access a Cisco Unified Communications Manager (CUCM) cluster (in your choice of CUCM version). You can even (virtually) get your hands on an IM and Presence server.

When I first discovered this, I actually felt guilty using it. After all, this resource is at Cisco’s DevNet site, and I’m not a developer. Fortunately, I was talking with one of Cisco’s DevNet folks at Cisco Live this year, and they told me it was not limited to developers. In fact, they encouraged me to let certification students know about this resource, and I’ve got to say it’s remarkable.

Please check out this new video I created to show...

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Your Framework for Cisco Exam Preparation

You want to get your first (or next) Cisco certification, but do you have a specific preparation strategy, or are you just winging it? If you do have a structured framework you’re confidently executing against, congratulations! If not, allow me to share my seven-step framework for Cisco exam preparation.

Step #1: Identify Your Training Source

When it comes to learning what you need to learn, the good news is, you’ve got options. Let’s compare a few:

Cisco Learning Partner

The traditional approach, and the way I trained certification candidates for nearly fourteen years, is to take an official Cisco course from a Cisco Learning Partner (CLP). You might have the option of taking your course at a training facility or on-line, and you typically get access to the gear you need to perform lab tasks during the course. You also get Cisco’s official course material. However, a gotcha that many people don’t realize is that Cisco typically has different groups...

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BPDUGuard: A Spanning Tree Protocol Enhancement

ccie r/s ccna r/s ccnp r/s Aug 30, 2016

Yet another new topic on the new CCNA R/S v3 exam is BPDUGuard, which is an enhancement to Spanning Tree Protocol (STP) available on our Cisco Catalyst switches. Specifically, BPDUGuard can help prevent a Layer 2 topological loop by placing a port configured for PortFast into an Error-Disabled state if that port receives a Bridge Protocol Data Unit (BPDU).

This video demonstrates the operation of BPDUGuard, and then trains you on how to configure this simple yet powerful feature.

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

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QoS Traffic Markings

One of the new topics on the new CCNA R/S v3 exam is Quality of Service (QoS). Having taught QoS for many years, I’ve noticed that one of the topics students find most challenging is QoS Traffic Markings.

This topic is all about how the binary math works behind the scenes to mark our traffic with specific levels of priority. So, to help demystify this topic, I created a new video (which is part of my upcoming CCNA R/S v3 Complete Video Course), and I wanted to share it with you. Enjoy!

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

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5 Tips for Your Technical Resume

career success Aug 09, 2016

You’ve earned your certifications. Maybe you have a college degree, and hopefully some technical experience. Now, it’s time to sell yourself to a prospective employer. We all know first impressions matter, and when it comes to the job seeker, that first impression is often in the form of a resume.

Personally, I’ve poured through tons of resumes while hiring Network Engineers when I was a Network Manager at a university. Of course, I’ve been on the other side of the table too, and have updated and fine-tuned my resume dozens of times.

Resumes need to quickly let a hiring manager get a sense for how you can help their company meet their objectives. Towards that end, let’s check out five quick tips for honing your technical resume.

Tip #1: Be Brief

A mistake I’ve made in my resumes, is being way too verbose. What I failed to realize is more is not necessarily better when it comes to resumes. A hiring manager is wading through a pile of resumes....

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APIC-EM Path Trace ACL Analysis Tool

Uncategorized Aug 02, 2016

When you’re reviewing the list of topics on the new CCNA R/S version 3 exam, one topic that’s sure to stand out is the APIC-EM Path Trace ACL Analysis Tool. That’s a very long name for a very new feature, and this video demonstrates it for you. Specifically, you’ll see how we can have the APIC-EM discover a network topology and then synthetically predict how traffic will flow (or be blocked) as it travels through a network.

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

If you enjoyed this article, you might also want to subscribe to my podcast:



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Software Defined Networking (SDN) Simplified

ccna r/s Jul 26, 2016

The recently announced CCNA R/S version 3 includes a collection of topics falling under the category of Network Programmability. The underlying technology here is Software Defined Network (SDN), which allows network device configurations to be orchestrated through software applications. Basically, instead of accessing a router or switch command line to enter traditional Cisco IOS commands, we can write a program (typically written in the Python programming language) to make changes to one or more devices. So, the purpose of this blog post is for you to learn the theory and architecture behind SDN.

The Promise of SDN

Traditional networks, where we individually configure routers and switches, simply do not scale well nor do they adapt well to dynamic environments. For example, maybe you run an e-commerce business, and you’re about to announce a big sale. To handle the anticipated spike in traffic, you spin up some virtual machines (VMs) and want to route a...

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