Cisco IOS v.12.4(15)T

Release 12.4(15)T, the sixth release of the 12.4T family, streamlines the Cisco IOS Software upgrade process, provides sub-second link failure detection and faster convergence, delivers next-generation Layer 2-7 flexible packet classification, enhances intrusion protection and SSL VPN capabilities, and provides support for the new Cisco 7201 Router, amongst other features.