Arista Networks (previously Arastra) is a computer networking company headquartered in Santa Clara, California, USA. The company designs and sells multilayer network switches to deliver software-defined networking (SDN) solutions for large datacenter, cloud computing, high-performance computing and high-frequency trading environments. Arista’s products include an array of 10/40/100 Gigabit Ethernet low-latency cut-through switches, including the 7124SX, which remained the fastest switch using SFP+ optics through September 2012, with its sub-500ns latency, as well as the 7500 series, Arista’s award-winning modular 10G/40G/100Gbit/s switch. Arista’s own Linux-based network operating system, EOS (Extensible Operating System), runs on all Arista products.
Andy Bechtolsheim co-founded Sun Microsystems in 1982 and was its chief hardware designer. In 1995, David Cheriton co-founded Granite Systems with Bechtolsheim, a company that developed Gigabit Ethernet products, which was acquired by Cisco Systems in 1996. In 2001, Cheriton and Bechtolsheim founded another start up, Kealia, which was acquired by Sun in 2004. From 1996 to 2003, Bechtolsheim and Cheriton occupied executive positions at Cisco, leading the development of the Catalyst product line, along with Kenneth Duda who had been Granite Systems’ first employee.
In 2004, the three then went on to found Arastra (later renamed Arista). Bechtolsheim and Cheriton were able to fund the company themselves. In May 2008, Jayshree Ullal left Cisco after 15 years at the company, and was appointed CEO of Arista in October 2008.
EOS is Arista’s network operating system, and comes as a single image that runs across all Arista devices or in a virtual machine. EOS runs on an unmodified Linux kernel under a Fedora-based userland. There are more than 100 independent regular processes, called agents, responsible for different aspects and features of the switch, including drivers that manage the switching ASICs, the CLI, SNMP, Spanning Tree Protocol, and various routing protocols. All the state of the switch and its various protocols is centralized in another process, called Sysdb. Separating processing (carried by the agents) from the state (in Sysdb) gives EOS two important properties. The first is software fault containment, which means that if a software fault occurs, the damage is limited to a single agent.The second is stateful restarts, since the state is stored in Sysdb, when an agent restarts it picks up where it left off. Since agents are independent processes, they can also be upgraded while the switch is running (a feature called ISSU – In-Service Software Upgrade).
The fact that EOS runs on Linux allows the usage of common Linux tools on the switch itself, such as tcpdump or usual configuration management systems. EOS provides extensive APIs to communicate with and control all aspects of the switch. As a matter of fact, its CLI is a collection of Python scripts that simply call into these APIs, while offering a so-called industry standard CLI that resembles the CLI in IOS. To showcase EOS’ extensibility, Arista developed a module dubbed CloudVision that extends the CLI to use XMPP as a shared message bus for managing and configuring switches. This was implemented simply by integrating an existing open-source XMPP Python library with the CLI.
Arista’s product line-up details are here.