The Promise of the Open Web: Is It Really Delivered?

Open network switches began to emerge in 2013, claiming to provide data centers with freedom and flexibility by eliminating proprietary software and improving return on investment. In a high-speed data-intensive world, network scalability and flexibility are critical to ensure that new services and hardware can be handled as efficiently as possible without compromising network performance, and to enable customers to adapt the network to specific business needs. Because traditional closed Ethernet switches are delivered on dedicated appliances, they limit the ability of data center managers to develop environments that can simply and effectively adapt to the needs of the largest market.

Open Networking was thus introduced, allowing users to gain control over their networks, with the promise that added differentiation to data center hardware would enable customers to achieve competitive advantage in terms of higher utilization and efficiency, as well as return on investment in network infrastructure.

Three to four years from now, it will be worth watching to see whether open networking has delivered on the benefits claimed above and whether it is on the right path to achieving truly open Ethernet switching.

The short answer is that open networking has actually made huge strides in enabling complete flexibility in choice of switch and software vendors. Two models have emerged under the open networking umbrella, offering different approaches to separating software and hardware in routing implementations.

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Switch system open

The first model is to introduce switch systems that are not locked to a specific software vendor. Its essence is to force customers to accept the relevant software on top of the hardware, where proprietary switches once dominated. Today's open network switches are white boxes on which users can install various software options. Drivers and controls are provided with the white box, and Open API allows the interface of any open network protocol or application, such as Quagga routing suite, OpenFlow agent and even vendor-developed applications.

Open Networking switches are designed to work with all available operating systems, whether native Linux, Cumulus Linux or MLNX-OS. In addition, when new operating systems such as Microsoft SONiC become available, Open Networking ensures that the switch system can be easily converted from one software package to another. Such software installation is achieved through the Open Network Installation Environment (ONIE) developed by Cumulus Networks and is open source. ONIE is specifically equipped to enable the switch system to work with any operating system.

Comparing this to closed system vendors such as Arista, Cisco, HP, Extreme, and Brocade, it is clear that the traditional solutions from these vendors are monolithic in that they only offer their own operating system as a software option.

Adding an abstraction layer

There is a second model that also provides freedom and flexibility to the data center. Open networking also supports open hardware that allows for an abstraction layer that separates switches and operating systems. The abstraction layer allows the software on top of it to be used transparently on different types of hardware, meaning that if a network deployment uses various types of hardware, they can all use the exact same software management, configuration, and monitoring tools. Additionally, any hardware upgrades do not require changes to the software.

There are two main abstraction layers currently in use: Switch Abstraction Layer (SAI) and switchdev. Each has its supporters and each has its advantages.

SAI is a user space application for the abstraction layer. The application drives the switch ASIC, bypassing the kernel, does not require any Linux kernel expertise, and can even change the hardware simply by changing the SAI driver. The main supporter of SAI is Open Switch, which is developed by HP and supported by OCP.

Switchdev is a kernel implementation of the abstraction layer. The switch state is saved in the kernel, not in the application, which means there is no need to rewrite existing Linux tools or create new ones. In fact, with switchdev, the switch is just like any other server, greatly reducing management and IT costs.

Eliminate lock-in

For too long, network customers have been locked into vendor-proprietary hardware and software solutions. The switch and router markets are dominated by a few vendors, resulting in limited solution flexibility and high procurement and service costs.

Until the advent of open networking, there was no alternative to purchasing network solutions from a small number of vendors. This vendor lock-in will be eliminated as switch platforms become open and abstraction layers are added, which will allow customers to choose software independent of their hardware.

Open Networking provides data centers of all sizes with the flexibility and freedom to use any software on their Ethernet switches, generating top-performing and scalable solutions that help them adapt and thrive in today's high-speed interconnected world.