Many network engineers find the entire world of telecom to be confusing—especially as papers are peppered with a lot of acronyms. If any part of the networking world is more obsessed with acronyms than any other, the telecom world, where the traditional phone line, subscriber access, and network engineering collide, reigns as the “king of…
Anyone who has worked with OSPF for any length of time has at least heard of areas—but perhaps before diving into Topology Transparent Zones (TTZs), a short review is in order. In this diagram, routers A and B are in area 0, routers C and D are Area Border Routers (ABRs), and routers E, F,…
I have not counted the IETF’s I have attended; I only know the first RFC on which I’m listed as a co-author was published in 2000, so this must be close to 20 years of interacting with the IETF community. I’m pretty certain I’ve attended at least two meetings a year in some years, and…
Low latency is coming to a network near you. In fact, it’s probably coming to your network, whether or not you realize it. This article was cross posted at APNIC While bandwidth has always been the primary measure of a network, and cross sectional or non-contending bandwidth for data center fabrics, further research and reflection…
On a recent history of networking episode, Alia talked a little about Maximally Redundant Trees (MRTs), and the concept of Depth First Search (DFS) numbering, along with the idea of a low point. While low points are quickly explained in my new book in the context of MRTs, I thought it worthwhile to revisit the…
Considering the DNS query chain— A host queries a local recursive server to find out about banana.example The server queries the root server, then recursively the authoritative server, looking for this domain name banana.example does not exist There are two possible responses in this chain of queries, actually. .example might not exist at all. In…
When deploying IPv6, one of the fundamental questions the network engineer needs to ask is: DHCPv6, or SLAAC? As the argument between these two has reached almost political dimensions, perhaps a quick look at the positive and negative attributes of each solution are. Originally, the idea was that IPv6 addresses would be created using stateless…
The argument for end-to-end encryption is apparently heating up with the work moving forward on TLSv1.3 currently in progress in the IETF. The naysayers, however, are also out in force, arguing that end-to-end encryption is a net negative. What is the line of argument? [time-span] According to a recent article in CircleID, it seems to…
From time to time, someone publishes a new blog post lauding the wonderfulness of BGPsec, such as this one over at the Internet Society. In return, I sometimes feel like I am a broken record discussing the problems with the basic idea of BGPsec—while it can solve some problems, it creates a lot of new…
Multi-Instance IS-IS One of the nice things about IS-IS is the ability to run IPv6 and IPv4 in the same protocol, over a single instance. So long as the two topologies are congruent, deploying v6 as dual stack is very simply. But what if your topologies are not congruent? The figure below illustrates the difference.…