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...]

Linux Network Interface Configuration With udev

I've recently been running down (or is it through) the Linux, systemd, networkd, udevd rabbit hole at full pelt and thought … [Read more...]

HTIRW: That Big Number Database in the Sky

As we come close to ending this rather long running series on how the Internet really works (because I'm certain you're about … [Read more...]

HTIRW: Internet Exchange Points

Most providers — transit, edge, and content — are pretty obvious to the various users of the Internet. Users interact with … [Read more...]


One of the various problems we face in the data networking world is the absolute plethora of tunneling technologies we have … [Read more...]



In this post we will look at something which is relatively new but not as cool as my previous post on Segment Routing. We … [Read more...]

Yet another blog about Segment Routing-Part 1

Segment Routing Fig.9

In this blog post we will be taking a deeper look at Node/Prefix SID and SR/LDP Interworking. If you work or have an interest … [Read more...]

RFCs You Should Know: 5218


Quite often RFCs in the "earlier days" discussed not only process but also design. Looking back now, considering the … [Read more...]

ISIS Link-Group

ISIS Link-Group

Introduction On the Core or Edge network, we need more and more bandwidth. For a large service provider, in some parts of … [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...]

BGP RR Design – Part 2

BGP RR Fig.10

This is a continuation from Part 1 9. ACME VPN RR's Design: So the current total number of PE's dedicated for VPN … [Read more...]

BGP RR Design – Part 1

BGP RR Fig.12

1. Introduction In this post we will be looking at large scale RR design by using a fictional ISP ACME  as a reference. As … [Read more...]

IP FRR and Micro-loops Part 2

IP FRR Fig.20

This is a continuation from Part 1 Remote LFA At this point we already know that simple LFA doesn't always provide full … [Read more...]

IP FRR and Micro-loops Part 1

IP FRR Fig.24

Introduction In this post we will take a look at IP FRR and Micro-loops. If the reader already doesn't have some kind of … [Read more...]

HTIRW: The IETF Draft Process

In our deeper investigations of the IETF as a "sample standards body" in this (apparently forever running) series on how the … [Read more...]