ISR4451-X-SEC/K9 Cisco ISR 4451-X Security Bundle Router

SEC bundle and forwarding license are separate

ISR4451-X-SEC/K9 is the Cisco ISR 4451 security bundle with a SEC license. Its platform provides four onboard Gigabit Ethernet interfaces, three NIM slots, one ISC slot and two service-module slots. Default aggregate throughput is 1 Gbps; Cisco identifies FL-44-PERF-K9 as the performance license for 2 Gbps. The SEC suffix does not itself establish that performance entitlement, APP rights, UC rights or a populated voice DSP.

Match the software train before retaining the router

Cisco lists IOS XE 17.9.x and 17.12.x as the last supported release trains for these affected ISR 4000 platforms, explicitly excluding 17.10.x and 17.11.x. This is a lifecycle boundary, not a recommendation to install any unreviewed maintenance version. Check module compatibility and the applicable security advisories before selecting a release for an existing configuration.

Distinguish maintenance from contract support

General software maintenance ended August 31, 2025. The hardware bulletin gives November 30, 2028 for vulnerability/security support and final support, subject to entitlement. New service attachment ended November 6, 2024, and renewal ends February 5, 2028. A device that boots today is not thereby eligible for a new Cisco service contract.

Use both exact migration rows

For ISR4451-X-SEC/K9, Cisco lists C8300-2N2S-4T2X and C8300-2N2S-6T as replacement options. Compare their actual interfaces, service modules and licensing against the deployed router before choosing. Preserve the existing routing, VPN, certificate and NAT requirements during that comparison; the replacement row does not promise automatic license transfer or configuration compatibility.

Cisco ISR 4451 interfaces and performance license | Cisco exact SEC bundle, software trains and migration rows