Friday, September 4, 2009

Open vSwitch Project Launches

Last week a new Open vSwitch project was launched with little fan fare and even less insight into who is behind the project. The project aims to create a multilayer virtual switch licensed under the open source Apache 2 license. At first glance the project looks very promising as the basis for creating distributed VLan and Virtual Private Clouds (VPC).

Before I go into the details of the project I will say I find it very interesting the complete lack of any insight into who is behind the project. The website doesn't include company or contact information. According to Alessandro Perilli at the project is backed by Citrix. In Perilli's post he points to a twitter post written in June by Citrix CTO Simon Crosby where Crosby used his Twitter account to calls for beta testers of the “XenServer distributed virtual switch”. But I couldn't find any mention of Citrix in either the Open vSwitch website or the whois records for According to the whois lookup, the website is registered to Martin Casado a student at Stanford with no affiliation with Citrix. Some further digging through the mailing archive I discovered the only real activity seems to be coming from a stealth company called Nicira.

Nicira describes themselves as "igniting a revolution in networking by creating a new software platform that will—for the first time—open up flexible, fine-grained control of wide area and virtual data center networks while dramatically lowering costs. The company was founded by networking research leaders from Stanford University and University of California at Berkeley, and is led by proven entrepreneurs in networking, security and virtualization. Nicira is advised and backed by recognized industry veterans, including Marc Andreessen, Diane Greene, Ben Horowitz and Andy Rachleff."

Back to why Open vSwitch is cool. According to the website the the goal of the project is to build a production quality switch for VM environments that supports standard management interfaces (e.g. NetFlow, RSPAN, ERSPAN, IOS-like CLI), and is open to programmatic extension and control. In addition, it is designed to support distribution across multiple physical servers similar to VMWare’s distributed vswitch or Cisco’s Nexus 1000v.

Open vSwitch currently supports multiple virtualization technologies including Xen/XenServer, KVM, and VirtualBox. The bulk of the code is written in platform-independent C and is easily ported to other environments.

The current release of Open vSwitch supports the following features:

  • Visibility into inter-VM communication via NetFlow, SPAN, and RSPAN
  • Standard 802.1Q VLAN model with trunking
  • Per VM policing
  • NIC bonding with source-MAC load balancing
  • Kernel-based forwarding
  • Support for OpenFlow
  • Compatibility layer for the Linux bridging code

The following features are under development:

  • User-space forwarding engine
  • sFlow
  • Compatibility layer for VDE
  • Ethernet over GRE (for ERSPAN and virtual private network creation)
  • Full L3 support + NAT
  • Priority-based QoS
  • More management interfaces (IOS-like CLI, SNMP, NetFlow)
  • 802.1x/RADIUS
  • Support for hardware acceleration (VMDQ, switching chips on SR-IOV NICs)
Check out the project at

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