The modern data center is the supercomputer re-invented. This is the reason why Cumulus Networks is taking a popular computer system OS and adapting it for networking. This grand large computer whilst made up of “compute nodes” and “storage nodes” interconnected by a network, still operates as a single system. For all practical purposes, it operates a lot like the shared use mainframes but enhanced by the ability to induct the most modern components, use the latest technologies and benefit from the economies of scale. The last point alone is what doomed the ever more complex mainframe computing paradigm.

Let us examine the things that a big iron box provided then. It allowed an application to lasso a collection of compute blocks, some storage elements and data elements and perform the task that is needed. The operating system logically connected all elements needed by an application and overlaid it on top of the system bus, thus allowing multiple applications to run on the same infrastructure.

Fast forward to today where scale out has replaced scale up as a way to build data centers. The modern data center is a collection of compute elements connected via a network. What used to be a thread is now a process running inside a virtual machine or a physical machine, and storage lives locally in a server or on a SAN. So what is needed is simply an ability to consistently and coherently connect the compute elements to each other and to storage irrespective of where they live and how they are physically connected. And voila, you get fast application delivery!


To achieve this goal, you just need two layers:

  1. A physical connectivity layer that uses standard mechanisms (let’s say IP/ethernet) and allows all end ports to connect to each other with massive bandwidth, multiple paths and QoS.
  2. A controller that connects subset of ports to each other exclusively and securely using logical ports layered on top of the physical connectivity layer.

Enter Cumulus Linux and VMware NSX controller shown below.


Cumulus Linux is the first Linux Distribution for networking gear and it’s finally bringing the economics of Linux to networking. It takes an industry standard networking box and makes it look like a server with a large number of 1G, 10G, or 40G NICs connected at wire-rate. The operating system accelerates the datapath in networking hardware using the existing Linux kernel constructs. So, Cumulus Linux IS Linux and customers can use the best automation, monitoring and orchestration tools onto their networking gear. Cumulus Networks teamed with a large ecosystem of hardware vendors to decouple networking operating system from networking hardware and provide the best hardware choice with no lock-in. The result is affordable, high capacity IP fabrics.

VMware NSX provides an abstraction to enable connectivity between any compute node on virtual networks. It decouples the physical network infrastructure from the virtual networks using overlay transports. In doing so, virtual networks can be spawned and destroyed on demand. VMware NSX also reproduces all the traditional network functions through a rich set of API that enables the best ecosystem of service nodes, gateways, and orchestration tools for network virtualization. The main overlay transport used is VXLAN. VXLAN is a standard Layer 2 overlay scheme over a Layer 3 network and it represents a unique virtual network or tenant. Besides the multi-tenancy flexibility, VXLAN scales the number of tenants to 16 Million tenants with a 24bit identifier.

Consider the many high performance applications such as Hadoop that will remain on physical servers, the backup servers, the services appliances, the legacy servers and their migration to virtual servers, the test platforms and their migration from virtual to physical server databases. Physical workloads need to access virtual networks and their entry point to the network is Top of the Rack switches. These Top of Rack switches are thus the logical place to connect physical workloads to virtual networks. Instead of being placed in a VLAN, physical ports are now placed in a VXLAN, and the Top of Rack switch’s job is to terminate VXLAN tunnels in hardware for the physical workloads attached to it. A switch supporting VXLAN tunnel endpoints (VTEP) is also referred to as a Layer 2 gateway switch.

This is the crux of the announcement we are making at VMworld. Cumulus Linux supports Layer 2 gateway services at wire rate on networking gear running Cumulus Linux. Multi-tenancy support wouldn’t be complete without a single point of orchestration for ALL workloads. This is where the integration of Cumulus Linux with VMware NSX is key. The Cumulus Linux switch registers with the VMware NSX Controller as a Layer 2 Gateway service, such that physical workloads attached to it can now be orchestrated and placed in virtual networks from one single point. Cumulus Linux presents itself as an Open vSwitch Data Base (OVSDB) agent and is managed by the NSX controller as an Open vSwitch.

Networks are no longer the bottleneck for application deployments. All networks are orchestrated from one single point of management. They are created, modified and destroyed with no performance impact in a matter of minutes and can react quickly to any application requirement.

Another great step for modern data centers… Software-only business models decoupled from hardware with automation, large scale orchestration, high performance for both the physical networks and the virtual networks… This is the reality today with Cumulus Linux and VMware NSX!