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Rethinking the Network

Marten Terpstra

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Top Stories by Marten Terpstra

IP Multicast is one of those technologies that most everyone loves to hate. It’s almost the perfect example of how complicated we have made networking. Getting IP Multicast to run depends on several protocols that are all somewhat intertwined or dependent on each, their relationship sometimes explicit, sometimes implicit. Even trying to describe the basic operation is complicated. When an application or service provides information using IP multicast, it simply starts sending it onto a specific multicast group. The multicast router for the subnet of the sender sees the incoming multicast packet and will initially have no forwarding information for that stream in its forwarding hardware. The packet is passed onto the CPU of that router, which will encapsulate this packet and send it towards a special multicast router designated the Rendez-vous Point (RP). When the RP... (more)

Training Wheels and Protective Gear By @PlexxiInc | @CloudExpo [#SDN]

Throughout the development cycle of new features and functions for any network platform (or probably most other products not targeted at the mass market consumer) this one question will always come up: should we protect the user of our product from doing this? And “this” is always something that would allow the user of the product to really mess things up if not done right. As a product management organization you almost have to take a philosophical stand when it comes to these questions. Protect the user Sure enough, the question came up last week as part of the development of on... (more)

Red Sox, Pumpkins and Packet Encapsulation

[This is not really about the Red Sox or pumpkins this Halloween, but how could I not use those in the title? Go Red Sox] I left an awful teaser at the end of my article last week. In Brent Salisbury's original article that triggered some of these additional virtualization thoughts, he articulated two very clear differences between native network based L2 virtualization mechanisms and the mechanisms that are being provided by overlay solutions based mostly in server vSwitch infrastructure. These two fundamental functions are MAC learning and tunnel encapsulation. In today's post... (more)

The Silence of The Lambdas

We still see quite a few eyebrows raised when we explain how we use WDM optics in our datacenter solution. In the various descriptions of the Plexxi solution it is often mentioned and referred to, but it is worth explaining what that optical infrastructure actually looks like and why it is part of our solution. One of the key attributes of the Plexxi solution is the ability to create network topologies at L1, L2 and L3 that meet the need of the workload offered, calculated based on the load on the network, and the Affinities created that describe the needs of specific applicatio... (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)