Internetwork Operating System (IOS) is a Cisco proprietary core software package implemented on almost all Cisco routers and switches. Cisco IOS software provides the intelligence of the Internet through a suite of value-added technologies and features. Cisco IOS comprises a sophisticated suite of networking capabilities that resides at the heart of such internetworking devices as standalone routers, router modules for shared-media hubs, switches, PC and workstation file servers, multiservice WAN access switches, and ATM-capable PBXs.

Key features of the Cisco Internetwork Operating System (IOS) include the following:

Reliable Adaptive Paths

Cisco IOS software provides protocol and routing support for all major internetworking protocol suites including IP, Novell NetWare, Apple AppleTalk, Banyan VINES, Digital DECNet, OSI, XNS, and Apollo Domain.

Bandwidth Optimization

The Cisco IOS architecture optimizes bandwidth by eliminating unnecessary traffic across wide-area network links and intelligently selecting the most economical WAN links available. The IOS capabilities such as virtual bandwidth reservation and priority queuing give network administrators the ability to reserve bandwidth and prioritize traffic based on the type of application, its source, or its destination.