Rethinking the Network

Marten Terpstra

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Top Stories by Marten Terpstra

The past few years have seen a dramatic improvement in the latency in network switches. Single ASIC based switches can all pretty much switch packets in less than a microsecond. Current 10GE switching silicon provides anywhere from 300 to 800 nanoseconds, specialized silicon shaves that to less than 200 nanoseconds when limiting the amount of searching that needs to be done by reducing the size of lookup tables. Even other solutions play some smart tricks by providing forwarding hints for intermediate switches make those lookups take less than 50 nanoseconds. Modular switches inherently have a higher latency. Line cards on modular switches typically have multiple ASICs, those ASICs are connected through a single or multi stage fabric. Each step takes time, resulting in latencies varying from around a microsecond when a packet stays on the same ASIC, to possibly 5-... (more)

Many Waze to Cambridge

I work mostly in Plexxi’s office in Nashua, NH. That is about a 12-minute commute for me, backroads only through two sleepy towns. Very convenient and a great improvement over my previous commute. Every now and again I make the trek out to our Cambridge office and it is painful. About 40 miles and around 45 minutes of mostly highway on a good day; early morning this is easily a 90-minute exercise, and finding myself on the road for two hours is not unusual. I am not very attached to a GPS, but whenever I travel a distance or know I am going to hit traffic, I turn on Waze on my p... (more)

Overlay Entropy

There have been many articles describing overlay networks in the past few quarters. It's a relatively straightforward concept, not far removed from some of the older VPN technologies very popular a while ago. The actual transport of packets is probably the simplest, it is the control plane that is much harder to construct and therefore explain. It is therefore also that the control plane in overlay networks has seen the most innovation and change, and is likely to change some more in standard and proprietary ways in the next little while. A perfect example is the use of IP Multic... (more)

Multisite Fabrics: Distance Does Not Have to Be a Challenge

Not entirely unexpected, the optical capabilities in our switch have provoked questions from customers and potential customers on whether the Plexxi solution could be used to create campus, metro or even long distance multi site fabrics. The answer to that question is a resounding yes, and with the newly introduced switch 2 platform, some of the connectivity options added to that platform make it extremely flexible to do just that. The whole topic of Data Center Interconnects tends to attract strong supporters and strong opponents at the same time. In a world without constraints... (more)

Network Autonomy – Feedback Defined Networking

About 8 years ago at my previous employer we started a project related to Autonomic Networking. Autonomic Networking is modeled after Autonomic Computing, an IBM initiative from the early 2000s, targeted at creating self managing computing elements. The network version intends to create a framework by which network elements become largely self managed. It does so by defining discovery, awareness and analytics that build some sense of state. Once a network has a sense of its expected state, anything that alters that state can be reacted to following a set of defined or even learne... (more)