Cisco IOS® Software is the world's leading network infrastructure software, delivering a seamless integration of technology innovation, business-critical services, and hardware support. Currently operating on millions of active systems, ranging from the small home office router to the core systems of the world's largest service provider networks, Cisco IOS Software is the most widely leveraged network infrastructure software in the world.
One of the most significant delivery milestones for Cisco IOS Software is the introduction of a new major release, which ships once every two years, delivers hundreds of advanced capabilities, and aggregates multiple prior releases into a synergistic whole.
Developed for wide deployment in the world's most demanding Enterprise, Access, and Service Provider Aggregation networks, Major Release 12.4 is a comprehensive portfolio of Cisco technologies, including the leading-edge functionality and hardware support introduced in Release 12.3T, anchored by an intensive stability and testing program.
Major Release 12.4 introduces more than 700 industry-leading features across the widest range of hardware in the industry. These key innovations span multiple technology areas, including Security, Voice, High Availability, IP Routing, Quality of Service (QoS), IP Multicast, IP Addressing, IP Mobility, Multiprotocol Label Switching (MPLS), and VPNs.
Cisco IOS Software Release 12.4 Introduction (PDF - 5.95 MB)
(All Cisco IOS Software Releases 12.4 Mainline Bulletins)
Cisco IOS Software Release 12.4 Features and Hardware Support
Cisco IOS Software Release 12.4: Security Features and Hardware
(All Cisco IOS Software Releases 12.4 Mainline Presentations)
(All Cisco IOS Software Releases 12.4 Mainline Q&A)