Most Recent Writings

Network Automation and Monitoring with Apstra AOS

Recently, I was lucky enough to attend Networking Field Day 19 where I saw many different presentations. One of the presentations I witnessed made me think about some of the operational aspects of managing a large-scale network, and I found the ideas presented by Apstra to be very interesting. Apstra’s AOS is built around the concept of Intent-Based Networking (IBN) ...
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Today I Passed the CCNA Industrial Exam

I found the CCNA Industrial certification to be interesting because like the Cisco Network Design certifications (CCDA/CCDP/CCDE), this single certification has quite an overlap of other certifications and technologies. Basic network design, security, wireless, and troubleshooting are added to the industrial networking protocols covered (CIP over EtherNet/IP and PROFINET). I found the exam to be fairly easy, but once again ...
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Connecting Multicast Islands with GRE

This post covers how to join together devices requiring multicast connectivity across networks that do not support multicast. This situation is common when the Internet is used for transport, and even in private networks such as MPLS L3VPN if the carrier does not support multicast (or you decided not to pay extra for that service). I will be using Cisco ...
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Easy Cisco VPLS L2VPN Automated Lab

In this lab, I cover automating the setup for a simple 3-customer VPLS L2VPN. I detail the basic configuration components, as well as automating the deployment to alleviate repetitive configuration commands. Like many technologies, it is best to start simple to build a foundation of knowledge before moving on to a more advanced depth. This lab is meant to be ...
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Today I Passed the CCNA Service Provider Exam

Or the CCNP Jr., as I've come to call it. Studying for this exam provides a nice overview of various service provider technologies and general architecture, as well as a glimpse into Cisco's service provider portfolio, including the IOS-XR operating system. This certification consists of two separate exams (SPNGN1 and SPNGN2), with no prerequisites. Several of Cisco's CCNA-level tracks require ...
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IPv6 6RD with Ubiquiti and DD-WRT

This posts walks through how to create an isolated network which has access to the IPv6 Internet via 6RD using Ubiquiti EdgeMax equipment and a router running DD-WRT. 6RD (Rapid Deployment) is a method to reach the IPv6 Internet by tunneling over an IPv4 network, similar to 6to4. While 6to4 is primarily used to connect different "IPv6 islands" together, 6RD was designed to ...
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Today I Passed the CCNA Wireless Exam

Wait, wasn't I just studying for the CCIE? After my lab attempt, I decided it was important to branch out a little bit and develop a more T-shaped skillset. I came from a generalist background (read jack-of-all-trades), then specialized in expert-level routing & switching which serves as a great foundation for other networking and infrastructure-related skills. Passing the CCNA Wireless ...
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MikroTik Automated MPLS L3VPN Lab

I am breaking out of the Cisco wheelhouse a little bit by using MikroTik RouterOS to build on my previous work of automating a base-level lab configuration. Working with another network operating system that uses a completely different syntax allows you to learn the various protocols in a more meaningful way (in my opinion). When you configure a single vendor's ...
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Easy Disaster Recovery Plan

DR plans encompass everything from no plan whatsoever (failing to plan is planning to fail), to active/active workloads distributed among several geo-redundant datacenters. This spectrum, just like nearly everything else in business, goes from zero to enormous cost and complexity. In the interest of keeping things simple, I designed a relatively inexpensive and uncomplicated enterprise DR plan that can be ...
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My First CCIE Lab Attempt

This is the unabridged version. The abridged version is available on LinkedIn. From the Written... Preparing, Part 1 Preparing, Part 2 Lab Day Part 1: TS Lab Day Part 2: DIAG Lab Day Part 3: CFG Aftermath Onward! From the Written... I passed the CCIE Routing & Switching v5.1 written exam in August 2017. It was a huge moment for ...
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Using Bridge Domain Interfaces on Cisco ASR-1K Routers

I am replacing an old Cisco 3945 router with a new ASR-1001X. The 3945, which has three gigabit Ethernet interfaces, has one connection to two service providers, and a single tagged link back to the network core carrying the traffic of a few different IP subnets. The ASR-1001X has six gigabit Ethernet interfaces, so when replacing the 3945 I wanted ...
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Automating Labs…Now With YAML and Multi-Threading!

The automation described in my last post had a couple of glaring flaws. I quickly discovered the inflexibility of using a CSV file for the data source as I started to add more variables to each device. The second flaw was that for approximately 30 devices, it took about 20 minutes to generate and push the device configurations, because each ...
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Automating Labs with Python, Jinja2, and Netmiko

Following up on my last post, I have set out to start automating certain aspects of my labs. I spent a few days going over the material from Kirk Byers' highly-recommend Python for Network Engineers course. I studied on the previous version of his course a couple of years ago (covering Python2), but this new version, which covers Python3, is ...
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Why Network Automation?

I have been wanting to get a little deeper into some various technologies surrounding MPLS and BGP-based VPNs (beyond basic L3VPN, such L2VPN, QoS, multicast, EVPN, etc.), so I assembled a virtual lab with approximately 30 routers which represent a service provider core and several "customer" sites, along with two sources of fake Internet connectivity (or more accurately, a simulated ...
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Mind Map for CCIE & CCNP Routing & Switching

I created a mindmap of topics that are covered on the current Cisco CCIE RSv5 lab exam to help myself study, and I thought my work might be useful to the general network community as well. I included CCNP R&S in the title, because there's a lot of overlapping information that I think most people pursuing the CCNP might find ...
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CCIE FlashCard Deck for R&S v5.1

Today I have decided to finally release the flashcard deck that I created for myself in order to pass the written portion of the CCIE Routing & Switching v5.1 exam. This deck represents many months and hundreds (if not thousands) of hours of study effort. After passing the exam, I had considered putting together some kind of study package, but ...
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Retrospection and the Future: Still Studying for the CCIE Lab

Last October marked the five-year anniversary of my blog. I had started an introspective post looking back over the past five years, but the truth is, I feel like I spend more time looking forward than backward at this point. That’s not to say I haven’t come quite a long way in the past five years. I sometimes need reminding ...
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Today I Passed the CCIE R&S v5.1 Written Exam

This is a big step for me, and has been a long time coming. I know I haven't "won" anything yet (I'm not going to be one of those people who put "CCIE written" on my resumé), but at the same time, passing this exam is a major milestone for me. The topic scope for the CCIE written exam is ...
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Cisco CCNP SWITCH Topics

Last year, I was not yet ready to take the CCIE R&S written exam, but my CCNP was about to expire. I decided to renew by taking the SWITCH exam, which had been revised since my original CCNP certification. I continued to study for the CCIE, but I focused my attention on topics that were on the SWITCH exam. As ...
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On Learning: Knowledge Management

For most knowledge-intensive fields of work, including network engineering, you must learn how to manage vast amounts of information if you wish to progress into more advanced levels. The first two articles in this series discuss creating and reviewing flash cards, which through spaced repetitions lead to dramatically increased knowledge retention. But what about static knowledge at-rest? Knowledge Management: Just ...
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On Learning: Flash Card Review

This part covers what I have learned about reviewing the flash cards. Flash Card Review: The premise of Anki (and related types of software) is spaced repetitions. To get the most out of the software, you need to make yourself get in the habit of reviewing your cards every single day. When you stop reviewing, you very quickly start to ...
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On Learning: Creating Meaningful Flash Cards

This is part one of a three-part series. I still study for the CCIE R&S. I study for it in some form (and often multiple forms) every single day. My attitude, thought processes, and learning process has changed quite significantly in the last year and a half. My experience is growing, and timelines are starting to become more concrete. I've ...
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How to Install Oxidized for Network Configuration Backup

Oxidized is an open-source project started by Saku Ytti and Samer Abdel-Hafez as an alternative to the very popular RANCID software. A little over a year ago, I created a RANCID server to backup the configuration of my network devices. It has been a good, stable piece of software that has been doing the job very well across hundreds of devices. When I set ...
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Today I Passed the CWNA Exam

I have been involved with both wired and wireless networking for many years. My original wireless setups were from the early 2000s, shortly after 802.11b became popular. I remember at one point I had a PCMCIA card with a pigtail and external antenna attached to it. As my career started taking a focus more toward networking, I became intimately familiar ...
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General Network Challenges, and IP/TCP/UDP Operations

Having fundamental knowledge of what affects TCP, UDP, and IP itself helps you to better troubleshoot the network when things go wrong. I feel like most of the lower-level network-oriented certifications barely touch on these topics, if at all. However, the current Cisco CCNP and CCIE Routing & Switching exams do expect you to know this. This post is geared ...
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QoS in Action

Quality of Service is an added-value network infrastructure service that is still very important within the scope of private networks. Some might argue that QoS is not as important as it once was as we start to see more SD-WAN deployments that utilize the general Internet for transport, because the Internet has no inherent QoS. Additionally, many private networks do ...
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The Data Center Move, Part 4

Part 1  |  Part 2  |  Part 3  | Part 4 Over the next couple of weeks, we continued to migrate more portions of the network and less-critical systems over to the new data center. One of the issues we experienced was temporary route instability due to accidentally advertising the same routes through multiple BGP ASNs because of redistribution. The ...
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The Data Center Move, Part 3

Part 1  |  Part 2  |  Part 3  | Part 4 After the servers were connected, we were getting complaints about intermittent connectivity. I would do a continuous ping against one of the servers, and it would randomly drop one or two packets out of every 20 or so, and then every 10 minutes it would completely lose connectivity for ...
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The Data Center Move, Part 2

Part 1  |  Part 2  |  Part 3  | Part 4 One of the nicest things about migrating the data center is we get a chance to start somewhat fresh and hopefully do things correctly (or rather, more “current” from a best practices perspective). As I’ve witnessed myself, network complexity builds up over time. Temporary “band-aid” fixes unintentionally become permanent ...
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The Data Center Move, Part 1

My posts are sometimes (nearly always) kind of long. I thought I'd try something different and break this one up into multiple parts. Part 1  |  Part 2  |  Part 3  | Part 4 Sometimes in life, the best experience comes from being in the right place at the right time. I studied enterprise networking for years while being employed ...
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Anki, My New Love

This post was also featured on PacketPushers.net Until now, I was never one to use flashcards. I could not see their value, and I was too lazy to actually write things down on a paper flashcard (and my handwriting is horrible). I recently discovered a program called Anki. On the surface, it is just a flash card program, but underneath, it ...
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Bringing an Old Mac Pro Back to Life with ESXi 6.0

It's been quite a while since I've done a purely technical post. The original Mac Pro is a 64-bit workstation-class computer that was designed with the unfortunate limitation of a 32-bit EFI. The two models this post discusses are the original 2006 Mac Pro 1,1 and the 2007 Mac Pro 2,1 revision. Both systems are architecturally similar, but the 2006 model ...
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Experiences with Cisco VIRL Part 2: INE’s CCIE RSv5 Topology on VIRL

This blog entry was also featured on PacketPushers.net VIRL topology + INE RSv5 ATC configs After getting VIRL set up and tweaked to my particular environment, my next step is to set up INE’s CCIE RSv5 topology, as this is what I will be using VIRL for the most, initially. I was satisfied with using IOL, but I decided to ...
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Experiences with Cisco VIRL Part 1: Comparing and Tweaking VIRL

This blog entry was also featured on PacketPushers.net Since it has been out for more than a year, and has been developed and improved tremendously during that time, I decided to finally take the plunge and buy a year's subscription to the Cisco VIRL software. Until now, I have been using any combination of real hardware, CSR1000Vs, and IOL instances for studying ...
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Hey, Wait…I Thought You Started Blogging in 2012?

It's true, I did start this blog in October 2012. In June 2018, I made the decision to prune all of my entries before December 2015. I spent a couple of hours reading over the majority of these entries and realized they are no longer relevant to my life and current career trajectory. When I started this blog, I was ...
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