Catalyst is the brand for a variety of network switches sold by Cisco Systems.While commonly associated with Ethernet switches, a number of different interfaces have been available throughout the history of the brand.

The latest version of IOS for the Catalyst 6500 series is 12.2(33)SXJ which enables In-Service Software Upgrade (ISSU) via IOS Software Modularity and 15.1.1-SY.

Some newer Catalyst switch models (with recent versions of the Cisco IOS) also allow configuration via web-based graphical interface (GUI) module which is hosted on a HTTP server located on the switch.

The IOS config-mode command 'ip http-server' will enable this style of configuration.

The Catalyst switches originally ran software called Cat OS rather than the more widely known Cisco IOS software used by routers.

However, this has changed as the product lines have merged closer together.

In some cases, particularly in the modular chassis switches, a configuration called 'Hybrid' has emerged - this is where the layer 2 functions are configured using Cat OS, and the layer 3 elements are configured using IOS.'Native IOS' can also be found with newer software versions that have eliminated Cat OS entirely in favor of IOS, even on hardware that originally required Cat OS.The 1700, 1900, and 2800 series Catalysts came from Grand Junction Networks, and the Catalyst 3000 series came from Kalpana in 1994.In addition, Cisco increasingly offers routers with switching capabilities; for example the Cisco 7600 series routers and the Catalyst 6500 series L3–switches have interchangeable parts.Even Cisco′s smaller routers, including their newest “ISR” series, can have switch modules installed in them, basically making Cisco′s smaller switches fully integrated devices.In most cases, the technology for the Catalyst Switch was developed separately from Cisco′s router technology.