Cisco IOS Software Release 12.4T integrates a portfolio of new capabilities, including security, voice, and wireless, with powerful hardware support to deliver advanced services for enterprise and access customers. It will be issued as a series of regularly scheduled individual releases, which Cisco will ultimately consolidate to form the next major release.

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.