Category: OpenFlow

Every single network device (or a distributed system like QFabric) has to perform at least three distinct activities:

• Process the transit traffic (that’s why we buy them) in the data plane;
• Figure out what’s going on around it with the control plane protocols;
• Interact with its owner (or NMS) through the management plane.

Routers are used as a typical example in every text describing the three planes of operation, so let’s stick to this time-honored tradition:

The last part of the ProgrammableFlow webinar described typical use cases including Cloud-as-an-Appliance, traffic steering (used by appliances like Radware DefenseFlow) and hypervisor switching with PF1000. Predictably, the use cases were followed by a lengthy Q&A session.

NEC and a slew of its partners demonstrated an interesting next step in the SDN saga @ Interop Las Vegas 2013: multi-vendor SDN applications. Load balancing, orchestration and security solutions from A10, Silver Peak, Red Hat and Radware were happily cooperating with ProgrammableFlow controller.

A curious mind obviously wants to know what’s behind the scenes. Masterpieces of engineering? Large integration projects ... or is it just a smart application of API glue? In most cases, it’s the latter. Let’s look at the ProgrammableFlow – Radware integration.

The true OpenFlow zealots would love you to believe that you can drop whatever you’ve been doing before and replace it with a clean-slate solution using dumbest (and cheapest) possible switches and OpenFlow controllers.

In real world, your shiny new network has to communicate with the outside world … or you could take the approach most controller vendors did, decide to pretend STP is irrelevant, and ask people to configure static LAGs because you’re also not supporting LACP.

Brent Salisbury sent me a link to a fantastic OpenFlow/SDN presentation Scott Shenker did @ Stanford University a few days ago. It’s a perfect introduction to the fundamental ideas behind SDN and therefore a must-see for everyone vaguely involved in networking.

Here are some of the highlights (from my highly biased perspective):

The SDN industry probably considers me an old and grumpy naysayer (and I’m positive Mrs Y has a special place in their hearts after her recent blog post), so I tried really hard to find a real-life example where OpenFlow could be used to solve mid-market innovator’s dilemma to balance my usual OpenFlow and SDN presentation.

The OpenFlow zealots are quick to point out the beauties of the centralized control plane, and the huge savings you can expect from using commodity hardware and open-source software. What they usually forget to tell you is that you also have to reinvent all the wheels the networking industry has invented in the last 30 years.

NEC demonstrated multi-vendor OpenFlow network @ Interop Las Vegas, linking physical switches from Arista, Brocade, Centec, Dell, Extreme, Intel and NEC, and virtual switches in Linux (OVS) and Hyper-V (PF1000) environments in a leaf-and-spine fabric controlled by ProgrammableFlow controller (watch the video of Samrat Ganguly demonstrating the network).

Does that mean we’ve entered the era of multi-vendor OpenFlow networking? Not so fast.

One of the most pleasant surprises of the recent Interop show was the Tail-f's Network Control System (NCS). I “knew” Carl Moberg (of the NETCONF and YANG fame) for a long time and had the privilege to meet him in person just before the SDN Buyer's Guide panel that I co-hosted with Kurt Marko (who did an excellent job putting the buyer's guide together). Anyhow, what Carl presented during the panel totally blew me away.

Hatem Naguib claimed that “the NSX controller cluster is completely out-of-band, and never handles a data packet” when describing VMware NSX Network Virtualization architecture, preemptively avoiding the “flow-based forwarding doesn’t scale” arguments usually triggered by stupidities like this one.

Does that mean there’s no packet punting in the NSX/Open vSwitch world? Not so fast.