PLUMgrid Plumbs Overlay Model for SDN

In the emerging world of Software Defined Networks (SDN), some embrace the OpenFlow model, while others prefer a different type of overlay approach. Networking startup PLUMgrid belongs in the latter camp.

PLUMgrid emerged from stealth today with $10.7 million in funding and its PLUMgrid Platform SDN overlay approach to present to prospective customers.

Awais Nemat, co-founder and CEO of PLUMgrid, explained to Enterprise Networking Planet that his company’s approach to SDN is absolutely not OpenFlow based. OpenFlow has emerged in recent years as the key open source protocol for enabling SDN. OpenFlow support typically needs to be explicitly enabled on a physical switch.

Instead of the OpenFlow approach, PLUMgrid uses an overlay approach that takes advantage of the VXLAN standard. VXLAN is a proposed IETF standard championed by multiple firms, including Cisco, Citrix, VMware, and Arista. With VXLAN, a Layer 2 network can be abstracted across the LAN.

The PLUMgrid Platform, which runs on an x86 server, creates an overlay network of what Nemat referred to as “virtual domains” across a network. The virtual domains become SDN components for service delivery and enable a network administrator to build self-service and self-provisioning networks and network services.

Instead of leveraging the open source Open vSwitch, available in the mainline Linux kernel as a server-based virtual switch, PLUMgrid uses its own virtual plumbing for switching, called the IO Visor.

“IO Visor is a virtualized I/O engine that allows for programmable network functions to be created on demand at run-time within the virtualized network domains,” Nemat said.

The IO Visor is deployed on each server for which the network administrator wants to have a PLUMgrid Platform-enabled virtual domain SDN. Nemat explained there there is also a gateway form factor to enable the onboarding of multiple servers and physical networking hardware. As a physical limitation, typical x86 servers do not have the same port densities for networking as physical networking gear. Nemat doesn’t see that as a bottleneck issue for the workloads that PLUMgrid is likely to be running.

“If each of the servers running PLUMgrid IO Visor have two 10 GbE Network Interface Cards (NICs), we don’t see a performance limitation at that speed,” Nemat said. “So if you’re deployed across 10 servers, the PLUMgrid platform is fully distributed, and the performance can scale out.”

That said, as network speeds and demand increase, Nemat noted that there will be a need for increased performance. To that end, he noted that his company is already working with silicon vendors to take care of future performance issues.


The PLUMgrid platform allows for a degree of extensibility by way of open REST APIs into the platform. While the platform as a whole can be extended, it’s not entirely standards-based either.

“What goes in and out of the system has to be standardized,” Nemat said. “The rest of it is about openness, which is way more important to people than whether something is a standard or not.”

In Nemat’s view, the ability to extend the system is the key to being open.

“The aspect of what software components are standardized by themselves in this new technology approach, which is not necessarily a mainstream technology, is something that we don’t see a huge resistance on today,” Nemat said. “But the question does come up.”

Sean Michael Kerner is a senior editor at Enterprise Networking Planet and Follow him on Twitter @TechJournalist.

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