Designing A Multi-Region, Multi-Hub Phase 3 DMVPN With BGP


I recently completed a design and lab scenario that uses Cisco DMVPN as a backup to a primary MPLS WAN (I’m still planning … [Read more...]

Campus LAN Design – A Different Approach


Throughout my career I have implemented a pretty large number of standard Cisco campus LAN designs. You know the model; a … [Read more...]

OpenStack Neutron – The Dirty Network Detail

OpenStack Neutron Networking

Update: I'm slowly getting there, third and more accurate diagram attached below which now includes where security policies, … [Read more...]

Routers vs Switches, When to position which?

Everyone knows the difference between a router and switch right? Good.. (for those that need a good refresher) this post is … [Read more...]

The Attributes of a Great Network Device API


What makes a good API? A device providing an API is only the start of the story; if its unusable, or unreliable its useless. … [Read more...]

Network Design Concepts Part-3

In the first article of the series, reliability and resiliency are covered. We should know that whatever device, link type or … [Read more...]

TCP/IP over VXLAN Bandwidth Overheads

A recent 'conversation' around VXLAN encapsulation and MTU with Matt Oswalt got me thinking about this subject recently. My … [Read more...]

Using VRFs to maintain security zones in an Layer 3 datacenter network

Layer 2 Network Diagram

The number of overlay technologies available today for the datacenter are numerous and highly functional. The flexibility … [Read more...]

Healthy Paranoia Show 20: SDN – Heretic of Security


The known universe has been ruled by the monolithic network device. In this time, the most precious substance in the … [Read more...]

Show 169 – Cisco FabricPath Deep Dive Part 1


Cisco FabricPath is a TRILL-based layer 2 forwarding technology that can take the place of spanning-tree. Allowing a … [Read more...]

Network Design Challenge – Small Little Clouds

At work, we've been getting ready to deploy a few different cluster technologies. One is a set of KVM hosts to offer VMaaS … [Read more...]

A Small Yellow Wooden Door: Thinking Practically About SDN


As I do most days, I took a walk in the woods at the back of my garden after a hearty dinner. I was quite surprised to come … [Read more...]

Show 135 – Change Control Causes Constipation


Ethan & I talk about recent events in the industry and their workday. I have a head cold so apologies for the sniffles / … [Read more...]

How to Draw Clear L3 Logical Network Diagrams


The biggest single problem I'm seeing when working on enterprise networks is the lack of L3 logical network diagrams. Most of … [Read more...]

Healthy Paranoia Show 6: Once Upon a Time, There Was Virtualization…

Unicorn Tears

Yes boys and girls, today we tell a story of clouds. The Packetpushers attack the subject of virtualization security. You'll … [Read more...]