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Rethinking the Network

Marten Terpstra

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Top Stories by Marten Terpstra

Last week Ivan Pepelnjak wrote an article about the failure domains of controller based network architectures. At the core of SDN solutions is the concept of a controller, which in most cases lives outside the network devices themselves. A controller as a central entity controlling the network (hence its name) provides very significant values and capabilities to the network. We have talked about these in this blog many times. Centralized Control When introducing a centralized entity into any inherently distributed system, the architecture of such a system needs to carefully consider failure domains and scenarios. Networks have been distributed entities, with each device more or less independent and a huge suite of protocols defined to manage the distributed state between all of them. When you think about it, it’s actually quite impressive to think about the extend o... (more)

Attention: Overlay Tunnel Construction Ahead

A while ago I wrote a few articles describing the various tunnel protocols used for network virtualization between vSwitches on servers, and between vSwitches and physical network gateways. These are the mechanisms that construct overlay networks on top of a physical network. VMWare uses STT as the tunneling mechanism between vSwitches on servers and VXLAN to communicate with gateways to the non virtualized world. NVGRE is used mostly by Microsoft, and is an extension to GRE tunneling that has been around for a while. Each one of these mechanisms have their pros and cons. They ... (more)

Open Compute, Open Switch API and Open Network Install Environment

Much has been published about the Open Compute Project. Initiated by Facebook, it has become an industry effort focused on standardization of many parts and components in the datacenter. Initially focused on racks, power and server design, it has also added storage and now networking to its fold. Its goal is fairly straightforward: “how can we design the most efficient compute infrastructure possible”, a direct quote from its web site. The focus of OCP has been mostly around hardware designs and specifications. If you look at the networking arm of OCP, you find several Top of Rack... (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)

Converging Your Storage Network Without Fear

The days of completely separate storage network technologies are quickly fading. It feels like it’s only a few years ago that Fiber Channel was the way to create large scale storage networks. Big honking storage devices on a separate network, connected to Fiber Channel switches, connected with Fiber Channel adapters into servers. With 10GbE becoming cost effective and matching or outperforming 2, 4 or even 8Gbit Fiber Channel, Fiber Channel over Ethernet was invented, mostly as a mechanism to allow Ethernet based attachments to existing Fiber Channel installations. It’s a bit clu... (more)