Clearing the fog around open switching terminology
Open switching has spawned a small lexicon that can be confusing to newcomers, leaving them wondering what the difference is, say, between bare metal switches and white box switches, and whether the differences really matter or are...
Lessons from Altoona: What Facebook's newest data center can teach us
How can Facebook's data center design apply to your data center plans?
The Case for /127 Subnets
In my previous post I wrote about all the positives we get from the almost incomprehensibly massive IPv6 address space, all there for our enjoyment if we will just break free of our long-ingrained IPv4 address conservation...
The Logic of Bad IPv6 Address Management
I've written about IPv6 address design previously, and in that post I briefly touched on the fact that our long-ingrained habits of IPv4 address design can lead us astray when working with IPv6. I'd like to revisit that topic, with...
IPv6 in the Enterprise May Happen Unexpectedly Fast
As I write this blog I’m sitting in the Rocky Mountain IPv6 Summit. Specifically, I’m sitting in the Enterprise track. And listening to an excellent lineup of speakers, I’m shifting some of my long-held views on IPv6 in the...
The Case for Enterprise IPv6
The business case for IPv6 in service provider networks – particularly broadband service provider networks – is all about the address supply, and you know the routine well: The IANA IPv4 address pool is gone, the APNIC, ARIN, and...
What's Next with IPv6?
We recently held the annual executive meeting of the Rocky Mountain IPv6 Task Force – which primarily consisted of eating sandwiches around Scott Hogg’s kitchen table – and a topic on the agenda was a discussion of future directions...
How Are Your Hexadecimal Skills?
I ended my post on IPv6 address design saying I would follow up by showing you a few simple tricks for working with hexadecimal numbers. Then the long-predicted depletion of the IANA pool of IPv4 addresses happened, I got distracted,...
Goodbye to a Couple of Old Friends
I have a couple of charts on IPv4 address depletion that I’ve used in presentations and customer reports for years. With today’s allocation of the last five IANA /8 blocks to the five RIRs, I’ve updated the charts for the last time,...
IPv4: The Beginning of the End
As predicted, IANA has allocated two /8 IPv4 blocks to APNIC. That brings the remaining IANA pool down to five, which triggers a plan to evenly allocate the remaining five /8s to the five RIRs. With the possible exception of AfriNIC...
IPv6 Address Design
There are a few culprits that regularly contribute to delayed or failed IPv6 deployment projects, such as poor DNS planning, insufficient testing, unanticipated application behavior, and poor IPv6 support in peripheral support,...
Can Large Scale NAT Save IPv4?
I've written previously that as we make the slow - and long overdue - transition from IPv4 to IPv6, we will soon be stuck with an awkward interim period in which the only new globally routable addresses we can get are IPv6, but most...
Understanding Dual-Stack Lite
The previous article examined a couple of basic Large Scale NAT (LSN) architectures – NAT444 and NAT464 – for creating dual stacked networks in the face of a depleted IPv4 address pool. The focus is primarily on broadband service...
Large Scale NAT Architectures
Traditional NAT, as discussed in the previous article, has been used for fifteen or so years to enable the sharing of a small number of public IPv4 addresses by a larger number of privately-addressed devices. In the case of homes and...
Understanding Carrier Grade NAT
Any general-use IP protocol stack that supports IPv6 also supports IPv4. That is, it is dual stack capable. “General-use” is an important qualifier here: Certainly there will be specialized devices that support only IPv6. But these...
The Dual Stack Dilemma
We are entering the transitional period between IPv4 andIPv6, and things are going to get awkward for a while. IPv4 addresses will officially be used up in the next couple of years, although for most practical purposes you can...
The Value of Information
One of my favorite stories (stop me if you’ve heard this one before) concerns an aged power station. One day the station failed, leaving the small town it served completely without electricity. The town managers called in several...
Confidence Levels and Calibration
Over the past several posts I’ve been discussing how networkers can reduce supposed “immeasurables” or “intangibles” to something that can in fact be measured, and I’ve been using Douglas Hubbard’s excellent book How to Measure...
Measuring the Immeasurable
I’ve been an avid skier for more than half my life. When we get our first light October snowfalls here in Colorado, I start getting serious about getting in shape. Sadly, this winter my consulting practice has been so busy that I...
Close Enough
In the previous post I wrote about the difficulty – quite common among networking and IT engineers – of expressing concepts that we understand in quantifiable terms that have meaning to the CFO or anyone else who must fund our...
