Understanding EIGRP – Part 2

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.

Understanding EIGRP – Part 1

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.

Accessing the Cisco DevNet Sandbox

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 a Cisco Unity Connection (CUC) server and 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 you how to get access to this incredible resource.

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

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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.

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Your 7-Step Framework for Cisco Exam Preparation


A Spanning Tree Protocol Enhancement

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).

APIC-EM Path Trace ACL Analysis Tool

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.

Software Defined Networking (SDN) Simplified

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.

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SDN Orchestrates Network Operations