Metaswitch today launched an open source project aimed at moving the virtual networking component of the NFV infrastructure from Layer 2 to Layer 3 of the network to achieve Internet scale in addition to greater simplicity and efficiency. (See Metaswitch Launches Open Source Project Calico.)

Project Calico is intended to become part of OpenStack, according to Metaswitch Networks CTO Martin Taylor. OpenStack is viewed within the NFV community as the likely option for virtual networking in the Network Functions Virtualization architecture designed by the ETSI NFV Industry Specifications Group.

Current implementations of OpenStack run at Layer 2, however, and that adds the complexity of using Ethernet virtual LANs or other forms of overlay networks and tunnels in order to support legacy enterprise protocols, he says. That involves a lot of encapsulation, or as Taylor puts it, "wrappering and un-wrappering."

Since today's NFV deployments and data centers are using IP-based network gear, it's more logical to adopt a Layer 3 approach, which reduces complexity, boosts scalability, and increases networking efficiency, he maintains. This less complex form of providing virtual networking becomes more important in the NFV world as service chaining begins and virtualized functions aren't contained to a single data center.

Metaswitch is offering Project Calico under a free software license via Apache License. Users, including service providers, can install OpenStack and then install Project Calico, which will take over the networking function of the default OpenStack deployment. Of course, Metaswitch will also sell a commercial version of the product, as well as support options for those who use the technology.

"It's a complete open source implementation," Taylor says. "That is the initial target for Calico. But this approach is also applicable to other types of cloud environments."

NFV focused
That may be where Project Calico gets even more interesting for NFV deployment. He sees a growing interest within the NFV community for what he terms "lightweight virtualization techniques," which don't always virtualize a complete machine image that includes an operation system. These more lightweight containers can support apps that piggyback off the host operating system, so that more instances of a given app can run on a physical machine, because space isn't eaten up by the OS.

"There are lots of use cases in the NFV space where this approach to virtualization makes more sense than the full-blown heavyweight full virtual machine approach typified by OpenStack," he says. So while OpenStack is the infrastructure of choice right now, other types of infrastructure using these lightweight containers are likely to show up alongside OpenStack.

Project Calico can provide a unifying network solution that works across those environments so that service chains can combine functions that are in full virtual machines with those that are in the lightweight container space. It can connect with physical boxes as well, which are likely to be part of the service provider infrastructure long after they have started the virtualization process.

He points to CoreOS, Docker, and Flynn as examples of up-and-coming players who are developing cloud solutions around the lightweight container idea. There is even the potential for Project Calico to make the orchestration of virtual functions easier, thus addressing a core problem for service providers that most admit is slowing their NFV deployment plans. For one thing, Taylor says, this removes the concern about the scalability of NFV infrastructure. In addition, it can simplify the orchestration of virtual network functions by removing many of the steps required to set up networking connectivity in a Layer 2 approach.

Metaswitch has been actively socializing Project Calico among other vendors, those in the OpenStack community and within the ETSI NFV ISG. Taylor expects the ultimate work that comes out of that group to incorporate the Layer 3 networking option for its virtual networking, although nothing is certain yet. He says there has been a "warm embrace" for the open source project among many in the NFV community, including service providers and vendors

Project Calico is built largely on open source resources, including those from OpenStack (the Neutron plug-in) and from the Linux kernel (layer 3 forwarding and more). Metaswitch has developed a Neutron plug-in for Calico and a software agent called Felix that provides forwarding table updates and security policies. It also allows users to determine which virtual machines can access a given application.

More information and downloads are available here.

— Carol Wilson, Editor-at-Large, Light Reading