Research: Measuring IP Liveness

12 November 2018 | 0 Comments

Of the 4.2 billion IPv4 addresses available in the global space, how many are used—or rather, how many are “alive?” Given the increasing usage of IPv6, it might seem this is an unimportant question. Answering the question, however, resolves to another question that is actually more important: how can you determine whether or not an…

Reaction: The Importance of Open APIs

22 October 2018 | Comments Off on Reaction: The Importance of Open APIs

Over at CIMI, Tom Nolle Considers whether the open API is a revolution, or a cynical trap. The line of argument primarily relates to accessing functions in a Virtual Network Function (VNF), which is then related to Network Function Virtualization (NFV). The broader point is made in this line: One important truth about an API…

BGP and Suboptimal Route Reflection

15 October 2018 | 2 Comments

One of the crucial points in understanding the operation of BGP is the reliance on the AS path to ensure all routes are loop-free. Within a single AS, however, there is no AS path. How, then, can you ensure the path through an AS is loop-free? The original plan was to fully mesh all the…

BGP Security: A Gentle Reminder that Networking is Business

24 September 2018 | 1 Comment

At NANOG on the Road (NotR) in September of 2018, I participated in a panel on BGP security—specifically the deployment of Route Origin Authentication (ROA), with some hints and overtones of path validation by carrying signatures in BGP updates (BGPsec). This is an area I have been working in for… 20 years? … at this…

Research: Tail Attacks on Web Applications

12 September 2018 | 1 Comment

When you think of a Distributed Denial of Service (DDoS) attack, you probably think about an attack which overflows the bandwidth available on a single link; or overflowing the number of half open TCP sessions a device can have open at once, preventing the device from accepting more sessions. In all cases, a DoS or…

Think Like an Engineer, not a Cheerleader

10 September 2018 | 1 Comment

When you see a chart like this— —you probably think if I were staking my career on technologies, I would want to jump from the older technology to the new just at the point where that adoption curve starts to really drive upward. Over at ACM Queue, Peter J. Denning has an article up on…

Is BGP Good Enough?

3 September 2018 | Comments Off on Is BGP Good Enough?

In a recent podcast, Ivan and Dinesh ask why there is a lot of interest in running link state protocols on data center fabrics. They begin with this point: if you have less than a few hundred switches, it really doesn’t matter what routing protocol you run on your data center fabric. Beyond this, there…

CLKscrew: Another side channel you didn’t know about

30 August 2018 | Comments Off on CLKscrew: Another side channel you didn’t know about

Network engineers focus on protocols and software, but somehow all of this work must connect to the hardware on which packets are switched, and data is processed. A big part of the physical side of what networks “do” is power—how it is used, and how it is managed. The availability of power is one of…

Reaction: Centralization Wins

27 August 2018 | Comments Off on Reaction: Centralization Wins

Warning: in this post, I am going to cross a little into philosophy, governance, and other odd subjects. Here there be dragons. Let me begin by setting the stage: Decentralized systems will continue to lose to centralized systems until there’s a driver requiring decentralization to deliver a clearly superior consumer experience. Unfortunately, that may not…

Research: Facebook’s Edge Fabric

23 August 2018 | Comments Off on Research: Facebook’s Edge Fabric

The Internet has changed dramatically over the last ten years; more than 70% of the traffic over the Internet is now served by ten Autonomous Systems (AS’), causing the physical topology of the Internet to be reshaped into more of a hub-and-spoke design, rather than the more familiar scale-free design (I discussed this in a…