Cisco IOS Guide

Part One:

Cisco IOS Software Family

Cisco IOS Software continues to evolve over time to meet the rapidly changing requirements of the most demanding Enterprise and Service Provider networks. As a family of releases, the feature richness and broad hardware support delivered in Cisco IOS Software is unmatched in the industry.

Table 1 summarizes the latest releases that make up the Cisco IOS Software Family:

Table 1—Cisco IOS Software Family Types and Releases

Type	Release	Description
IOS T	Maintenance Release 12.3 Maintenance Release 12.4	A comprehensive portfolio of Cisco IOS Software technologies and broad hardware adoption for Enterprise, Access, and Commercial networks. Incorporates new software features and hardware introduced in the earlier T release, and additional software fixes. Maintenance releases inherit new Cisco IOS Software functionality and hardware from T releases. This is typically new functionality. Hardware is not introduced in maintenance releases.
	Release 12.4T	Cisco IOS Software functionality and hardware advances for Security, Voice, and Wireless for Enterprise, Access, and Commercial networks.
IOS S	Release 12.2SB	Cisco IOS Software functionality and hardware for Broadband and Leased-Line Aggregation, and MPLS Provider Edge (PE) on a comprehensive portfolio of mid-range routers for Service Provider edge networks.
	Release 12.2SX	Cisco IOS Software functionality and hardware for high-end Ethernet LAN switching for Enterprise access, distribution, Core and data center networks.
	Release 12.2SE Release 12.2SG	Cisco IOS Software functionality and hardware for mid-range and low-end Ethernet LAN switching for Enterprise access and distribution networks, and mid-range and low-end Metro Ethernet for Service Provider edge networks.
	Release 12.2SR	Cisco IOS Software functionality and hardware for high-end Metro Ethernet and MPLS PE for Service Provider edge networks.
IOS XR	Release 3.2	Cisco IOS XR Software functionality and hardware for the Cisco CRS-1 Carrier Routing System and Cisco XR 12000 Series Routers for Service Provider Core networks. Designed to address the terabit scaling, secure virtualization, high availability, and distributed processing requirements of large IP next-generation networks.

Cisco IOS Software Family Hardware

Table 2 correlates Cisco hardware to the recommended Cisco IOS Software Family release.

Table 2—Cisco IOS Software Family Hardware

Hardware	Recommended IOS T, IOS S, IOS XR
Access and Dial Routers
Cisco 800, 1700, 2600, 2800 Series Routers	12.4 12.4T
Cisco 3700 and 3800 Series Routers	12.4 12.4T
Cisco AS5x50	12.4 12.4T
Switches
Cisco Catalyst 2970, 3560 and 3750 Series	12.2SE
Cisco Catalyst 4500 and 4900 Series Switch	12.2SG
Cisco Catalyst 6500 Series Switch	12.2SX
Mid-Range Hardware
Cisco 7200 Series and Cisco 7301 Routers	12.4 12.4T 12.2SB
Cisco 7304 Router	12.2SB
Cisco 7500 Series Router	12.4 12.0S
Cisco 10000 Series Router	12.2SB
High-End Hardware
Cisco 7600 Series Internet Router	12.2SR
Cisco 8550 MGX RPM-PR/XF Router	12.4T
Cisco 12000 Series Router	IOS-XR, 12.0S
Cisco CRS-1 Carrier Routing System	IOS-XR