PLUMgrid

PLUMgrid develops virtual network infrastructure for cloud environments. Its software-defined networking (SDN) platform delivers multi-tenancy, security, and scalable performance crucial for complex data center networks. This software approach creates a virtual infrastructure paralleling physical networks, enabling agile operations within cloud deployments.

Founded in 2011 by Awais Nemat, Pere Monclus, and Sushil Singh, PLUMgrid emerged from their extensive engineering experience at Cisco. Their insight was the need for a software-driven, programmable network architecture to address traditional networking limitations in the burgeoning cloud era, aiming for flexible virtual networks.

PLUMgrid's solutions targeted enterprises and service providers managing substantial cloud infrastructure, particularly OpenStack users. The company's vision focused on open, software-defined networking that streamlined management, boosted automation, and accelerated application deployment, building a foundation for dynamic cloud environments.

# PLUMgrid: A Software-Defined Networking Pioneer

High-Level Overview

PLUMgrid was a software-defined networking (SDN) startup that developed secure and scalable virtual networking solutions for OpenStack clouds.[1] Founded in 2011, the company positioned itself as a leader in network virtualization, automation, and security, offering a platform-based SDN architecture designed to work across any hypervisor, container, device, and hardware.[4] Rather than competing directly with established players like VMware's NSX, PLUMgrid took a differentiated approach by creating IO Visor, an innovative I/O processor embedded in the Linux kernel that controlled virtual domains for network virtualization, monitoring, and security.[2] The company served hybrid data centers and cloud environments, enabling efficient connection of tenants, applications, and workloads across virtualized, bare metal, and container-based architectures.[1]

At its peak, PLUMgrid had raised $27 million in venture funding, including a $16.2 million Series B round in 2014, and operated with approximately 87 employees from its Santa Clara, California headquarters.[1][2] However, the company ultimately could not sustain itself in an increasingly competitive market dominated by well-capitalized incumbents, leading to its acquisition by VMware in December 2016.

Origin Story

PLUMgrid was founded in 2011 by a group of former Cisco engineers, including Pere Monclus (founder and CTO) and co-founders Awais Nemat and Sushil Sinha.[3][5] Monclus and his team emerged during a fertile period for SDN startups, when the programmable data plane and virtualized network functions were attracting significant entrepreneurial attention and venture capital investment.[3] The company formally introduced its technology in 2013, positioning itself within the early wave of startups attempting to capitalize on the SDN revolution.[2]

The founding team's Cisco pedigree was significant—these were engineers who had worked on some of the networking giant's most important technologies, giving PLUMgrid credibility and technical depth from inception.[5] The company's early traction included notable customers such as Swisscom, which became both an investor and early adopter, and NTT SmartConnect, a streaming video service built on OpenStack cloud infrastructure.[2] In mid-2015, recognizing the need for experienced leadership as market conditions tightened, the company brought in Larry Lang, another Cisco veteran, as CEO to navigate the increasingly challenging funding environment.[2][5]

Core Differentiators

IO Visor Technology: PLUMgrid's flagship innovation was IO Visor, an I/O processor that operated within the Linux kernel rather than functioning as a traditional SDN controller.[2] This architectural choice represented a fundamental departure from competitors like Nicira (acquired by VMware) and Big Switch Networks, which built SDN controllers to dictate instructions to switches. IO Visor's kernel-level approach provided more direct control over virtual domains and network functions.[2]

Open Source Commitment: The company demonstrated strong commitment to open source development, contributing IO Visor to the Linux Foundation where it became an official project.[2][3] PLUMgrid also contributed code upstream to the Linux kernel itself, including extended Berkeley Packet Filter (BPF) and Express Data Plane (XDP) technologies, which transformed how the kernel handled networking operations.[4]

OpenStack Integration: While competitors focused on proprietary cloud platforms, PLUMgrid strategically positioned itself as an OpenStack companion, offering its software networking solutions specifically designed for OpenStack-based cloud environments.[2] This approach aligned with the company's philosophy of working within open source ecosystems rather than against them.

Comprehensive Platform: PLUMgrid offered a suite of products including the Open Networking Suite, Container Networking Suite, CloudApex, and CloudSecure, providing network virtualization, automation, and security capabilities across diverse infrastructure types.[4]

Role in the Broader Tech Landscape

PLUMgrid emerged during a critical inflection point in cloud infrastructure evolution. The early 2010s saw explosive growth in virtualization and cloud computing, creating demand for sophisticated network virtualization solutions that could manage complex multi-tenant environments. The company rode the wave of OpenStack adoption, positioning itself as the networking layer for organizations building private and hybrid clouds.[2][4]

However, PLUMgrid faced headwinds from larger, better-capitalized competitors. VMware's NSX (originating from the Nicira acquisition) and Cisco's Application-Centric Infrastructure (ACI) dominated the market with superior resources and established customer relationships.[2] The 2015 funding environment shift—from the "unicorn madness" of 2014 when startups burned cash aggressively to a more disciplined focus on profitability and business models—particularly disadvantaged PLUMgrid.[5] By August 2015, the company was forced to take a $2.45 million bridge loan, signaling financial distress.[5]

Despite these challenges, PLUMgrid's technical contributions proved durable. IO Visor's integration into the Linux kernel and its adoption by the Linux Foundation ensured that the company's core innovation would outlive the company itself, influencing how the broader industry approached kernel-level networking and data plane programmability.[3][4]

Quick Take & Future Outlook

PLUMgrid represents a cautionary tale about timing and market dynamics in enterprise infrastructure software. The company possessed strong technical talent, innovative architecture, and genuine open source contributions, yet could not overcome the gravitational pull of established players with deeper resources and broader platform ecosystems. When VMware acquired PLUMgrid's assets and employees in December 2016, it was a strategic move to strengthen VMware's SDN and OpenStack capabilities rather than a rescue of a thriving business.[4]

The acquisition proved mutually beneficial: VMware gained valuable SDN intellectual property and engineering talent to enhance its cloud and virtualization offerings, while PLUMgrid's technology and team found a sustainable home within a market leader. More importantly, PLUMgrid's open source contributions—particularly IO Visor and kernel-level networking innovations—transcended the company's commercial fate, becoming foundational technologies that influenced how the industry approached software-defined infrastructure for years to come. In this sense, PLUMgrid's legacy extends beyond its corporate existence, embedded in the Linux kernel and open source projects that continue to shape cloud networking architecture.