Rethinking the Network

Marten Terpstra

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Top Stories by Marten Terpstra

Earlier this week, Ethan Banks wrote a very nice article about Mellanox’s dual spine and leaf network in support of a large amount 10GbE access ports. After describing the scaled up network design, he reviews 8 observations about the design, not to point out good or bad, but merely to point out specific points to consider. Fully coincidental (Ethan lives close to us, but I am pretty sure he cannot peek through our windows) we had gone through a similar exercise this week, documenting the choices and limitations of spine and leaf networks. And as always, the conclusions are not ones of right or wrong, more of awareness of choices and consequences. The Mellanox design Ethan describes employes an extra spine layer, we have seen and heard the same from Arista and others, some calling it a spine-spine or similar. Nitpicking perhaps, but adding a spine layer to a spine and... (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)

Aggregation Is Good. Aggregation Is Bad.

For as long as I remember networking has struggled with the balance between aggregated and individual traffic flows. Following the abilities of the technology components we use, we have been forced to aggregate, only to be allowed to de-aggregate or skip aggregation when technology caught up or surpassed the needs of today. The vast majority of networking equipment is driven by specialized hardware. For datacenter switches, speed and port density are driving the requirements and physics and our technology capabilities create trade-offs that ultimately lead to some form of aggreg... (more)

Different Shades of Invisible

We love analogies. No matter what the topic, analogies are a great way to explain something in a different context to make a specific point with a frame of reference that may be more familiar to those we are making a point to. There is one that seems to come back over and over again in our industry, the one that compares the network to the power grid, network connections to power plugs.  I had not heard it for a while but at Interop last week, I heard it used twice in booth demonstrations as part of plug and play pitches. And I really do not like that analogy. The comparison to ... (more)

Network Services, Abstracted and Consumable

Perhaps not as popular as its brothers and sisters I, P and S, Network-As-A-Service or NaaS has slowly started to appear in industry press, articles and presentations. While sometimes associated with a hypervisor based overlay solution, its definition is not very clear, which is not at all surprising. Our industry does not do too well in defining new terms. I ran across this presentation from Usenix 2012 that details a NaaS solution that adds a software forwarding engine to switches and routers that provide specific services for some well known cloud computing workloads. I have ... (more)