Networking

Networking · 13 min read

What NFD40 Taught Me About AI Networking

2026.07.07

I went into NFD40 thinking the AI networking pitches were going to be the marketing layer dressed up in new vocabulary, and I came out convinced it’s a different design problem.

Networking · 12 min read

ARIN at CHI-NOG 13: The State of Routing Security

2026.06.09

I sat in Brad Gorman’s RPKI workshop at CHI-NOG 13 with the kind of attention you give a talk when somebody on stage just admitted the security model has known holes.

Networking · 7 min read

Ethernet Commoditizes Everything. Except EOS

2026.04.30

Halfway through Tom Emmons’ scale-out segment at NFD40, a fellow delegate looked at Arista’s load-balancing slide and said what most of us were thinking… this could have any vendor’s logo on it.

Networking · 7 min read

Nokia at NFD40: Networking in the AI Era

2026.04.15

I’ve been building networks for nearly thirty years. I understand leaf-spine fabrics, BGP design, VRF isolation, ECMP, and congestion management.

Networking · 2 min read

IP Infusion powering the world from behind the scenes

2017.08.01

Founded by Kunihiro Ishiguro and Yoshinari Yoshikawa the founders of GNU Zebra, came together to form IP Infusion back in 1999 as a commercial-grade, hardware-independent networking software company.

Networking · 4 min read

VMware NSX is something something awesome

2017.07.31

At times I have trouble focusing on writing articles for some of the presentations I am exposed to at Tech Field Day. Because of that, I really wanted to try something different.

Networking · 5 min read

BGP Communities

2015.02.10

BGP Communities has to be one of my favorite features added to the BGP protocol.

Networking · 4 min read

AS-Path Filtering

2014.10.15

Before we get into the how, let’s talk about the why.

Networking · 2 min read

HP talks SDN at Interop NYC 2014

2014.10.07

I generally try to avoid oversharing when it comes to my thoughts about presentations, but I have to mention that after sitting down with Glue Networks and their “SDN” presentation, it was truly a …

Networking · 4 min read

Cisco Nexus 2000: A Love/Hate Relationship

2012.06.21

My feelings towards the Nexus 2000 Fabric Extender (FEX) are hardly a secret. The myriad of design choices and platform limitations present engineers with some rather difficult decisions.

Networking · 3 min read

QinQ: IEEE 802.1Q Tunneling

2012.04.19

In situations where service providers want to offer transparent LAN services that preserve a customers VLAN tags across your Layer-2 network, this amendment to the IEEE 802.

Networking · 5 min read

MDS Fibre Channel Switching Basics for Network Engineers

2011.12.23

Recently I’ve been lucky enough to be challenged with learning a bit about Fibre Channel Switching, but I’m even luckier in that I’m getting to know it on a set of MDS switches running NX-OS …

Networking · 4 min read

Juniper QFabric, Junosphere, Automation, and More

2011.11.04

The second day of Networking Field Day 2 started early at the Juniper EBC, luckily Abner Germanow was prepared with breakfast for the weary and slightly hung over delegates.

Networking · 4 min read

Network Duct Tape Gone Wrong

2011.09.01

As many of you may know, I’m in the middle of a huge network redesign, last week our new firewalls finally arrived and it became time for us to start migrating services onto the edge network I’ve been …

Networking · 2 min read

F5’s iRules — My first look

2011.08.29

I’ve never had the opportunity to really do much with F5 load balancers in the past, but recently one our system engineers needed some load balancing setup, and wanted to know if we could assign some …

Networking · 4 min read

Nexus 7000 vPC Features

2011.08.19

Next generation data centers across the world are taking advantage of Cisco’s Virtual PortChannel.

Networking · 2 min read

NX-OS 5.2(1) for the Nexus 7000

2011.08.01

Rather quietly, at least I never heard anything, on July 29th, Cisco released NX-OS Version 5.2(1) for the Nexus 7000 platform.

Networking · 3 min read

IP SLA Basics

2011.05.06

IP SLA is a function of Cisco’s IOS enabling you to analyze a Service Level Agreement (SLA) for an IP application or service.

Networking · 6 min read

IP Multicast Routing Concepts

2011.03.28

Can you imagine a video conference taking place on a primarily T1 based WAN? Multiple copies of the same video stream being unicast from the host to each participant.

Networking · 2 min read

SVI Autostate

2011.03.07

Switch Virtual Interfaces, or SVIs on Cisco IOS use a feature called autostate to determine the interface availability.

Networking · 3 min read

Introduction to the Nexus 1000V

2011.02.24

The Nexus 1000V is a software-based Cisco NX-OS switch that integrates into VMware vSphere 4 and operates inside the VMware ESX hypervisor.

Networking · 5 min read

OSPF Graceful Shutdown

2011.02.21

Striving to reach that last 9? Looking for a way to increase your uptime while still being able to do maintenance on your network? Wish you could shutdown your OSPF neighbors like your BGP peers?

Networking · 7 min read

IOS Embedded Packet Capture

2011.02.14

Tired of setting up SPAN sessions? Need to do some packet analysis? Since IOS 12.4(20)T Cisco has made Embedded Packet Capture (EPC) available.

Networking · 4 min read

Nexus Virtual Port Channel (vPC)

2011.02.01

The Nexus 7000 and 5000 series have taken port-channel functionality to the next level by enabling port-channels to exist between links that are connected to different devices.

Networking · 5 min read

Setting up a Cisco Access Server

2011.01.24

Whether your networking lab has 3 devices or 30 an access server, also commonly called a terminal server, is the vital connection between you and those devices.

Networking · 5 min read

HSRP, VRRPd, and GLBP Compared

2010.10.21

In the world of first hop redundancy, we have plenty of choices. In order to make the right decision for your network you should know the basics regarding all three.

Networking · 3 min read

BGP Tips! multipath load balancing

2010.10.14

Previous thoughts on load balancing BGP were that it is not a load balancing protocol and in order to achieve any sort of balanced traffic you would have to perform some sort of route balancing.

Networking · 5 min read

More IOS Tips

2010.06.09

Learning the particulars of Cisco IOS is one of the most valuable things a network engineer can do. These skills will be the basis of everything you do on the lab and on your network.

Networking · 3 min read

Using the Cisco IOS Archive Command

2010.06.07

The Cisco IOS archive command is not only very useful in keeping configuration archives, but it can also be used to log commands entered into the router, along with their user name.

Networking · 4 min read

Introduction to Private VLANs

2010.06.01

The concepts behind Private VLANs are in fact rather simple, but it is quite easy to get discombobulated in the details.

Networking · 6 min read

Bidirectional Forwarding Detection

2010.05.24

Bidirectional Forwarding Detection (BFD) is a UDP-based protocol that provides fast (very fast!) routing protocol independent detection of layer-3 next hop failures.

Networking · 1 min read

Measuring Cable Lengths on a Catalyst Switch

2010.05.22

A while back, I was playing on a 3750 switch in a customers lab and came across something I’ve never seen before. It seems that some Cisco switches have a built in Time-domain reflectometer, or TDR.

Networking · 4 min read

Using Regular Expressions on Cisco IOS

2010.05.16

As a followup to my previous post on Regular Expression Basics, I wanted to give a few examples on using them on Cisco IOS.

Networking · 2 min read

More BGP tricks

2010.05.16

At times, the ‘rules of BGP’ don’t fit the needs of our productions networks. When we get into today’s production networks how often do book configurations apply? I’ll tell you one thing.

Networking · 6 min read

Cisco VOIP Basics – Call Broadcast for Cisco CME

2010.04.23

This is the fourth and final part of my Cisco voip basics series. ( Parts 1, 2 & 3 ) Our goal in this series has been setting up a working voice gateway that you could use in your home office.

Networking · 3 min read

Policy Based Routing

2010.04.05

Policy based routing is the process of altering a packets path based on criteria other than the destination address, commonly referred to as ‘policy routing’.

Networking · 4 min read

IOS ACL Resequencing

2009.11.23

This is one of those tricks you wish you learned about 10 years ago, but never did. You know how easy it is to mess up a nice looking access list.

Networking · 11 min read

Cisco MPLS VRF Configuration and Demo

2009.11.19

A while back I asked everyone to vote on what topic they wanted to see next, and by no surprise almost every voted for MPLS VRFs.

Networking · 1 min read

JunOS Olive Demonstration

2009.10.04

As a follow up to my JunOS Olive tutorial, I made a demonstration video that shows Multicast functioning via OSPF to another Olive and an ImageStream VM.

Networking · 7 min read

Route Selection

2009.09.14

One of the most common questions I get concerns path selection within the router.

Networking · 6 min read

Cisco VOIP Basics – Cisco Dial Plans

2009.09.08

This is the third part of my Cisco voip basics series. ( Parts 1, 2 & 4 ) Our goal is to help you configure a Cisco voice gateway that you could use in your home office.

Networking · 2 min read

Testing TCP Connectivity on Cisco Devices

2009.08.23

Ever thought you might be having some Layer 4 connectivity issues? Pings as you should know are ICMP transmissions and ICMP is a Layer 3 protocol (commonly used to send error messages).

Networking · 5 min read

Cisco VOIP Basics

2009.08.20

This is the first part of my Cisco voip basics series. ( Parts 2, 3 & 4 ) VOIP is obviously becoming a large part of networks, even now part of your CCNP requirements are basic voip knowledge.

Networking · 2 min read

Configuring a Cisco Router as a Frame Relay Switch

2009.08.06

One of the most effective lab setups uses frame relay as its primary transport method. This is a configuration that many people use and praise for its ease of setup and maintenance.

Networking · 1 min read

Setting up VOIP lab

2009.06.13

This week I’ve started setting up a VOIP lab to explore the technology and when I’m done, I plan to integrate it into my home network.

Networking · 1 min read

Demystifying Cisco Config Register Bits

2009.06.08

Ever accidentally set your config register to a random value that isn’t in the Cisco documentation? No? Neither have I, but one day I encountered someone on #cisco that had.

Networking · 3 min read

Cisco IOS Tips and Tricks

2009.05.27

So, I’m sure these have been posted almost on every networking blog under the sun, but who knows, right?

Networking · 2 min read

Cisco IOS Naming Conventions

2009.03.16

As I started building this lab, I realized that I had to find a refresher course on the IOS naming conventions.