C1-CISCO4351/K9 - Cisco One 4000 Family Integrated Services Router

C1-CISCO4351/K9 Platform and Rights Check

C1-CISCO4351/K9 is the Cisco ONE ISR 4351 hardware order with IP Base. Cisco's lifecycle table maps this exact Cisco ONE PID to the standard ISR4351/K9 hardware order; it is not the smaller ISR4321 platform.

Expansion capacity defines the 4351

Three onboard Gigabit Ethernet interfaces, three NIM slots, one ISC slot and two service-module slots. 4 GB Flash and 4 GB DRAM by default. The two service-module positions and third NIM slot are material differences when reusing existing WAN, switching, compute or voice modules.

Performance entitlement is separate

ISR4351 base performance is 200 Mbps; FL-4350-PERF-K9 increases the documented level to 400 Mbps. Confirm the license inventory on the actual serial number. The C1 prefix or a seller description does not prove that a performance upgrade, boost license, security package or application entitlement transfers with used equipment.

Cisco ONE commercial boundary

Record the original Cisco ONE order, Smart Account or license evidence and current IOS XE registration. Treat software rights as unverified until entitlement ownership and transferability are documented; the physical router alone is not proof of a usable software suite.

Lifecycle and replacement

Cisco ended sale of this C1 hardware order on October 28, 2022. Routine software maintenance ended October 28, 2023, vulnerability support ended October 27, 2025 and the listed last date of hardware support is October 31, 2027. Cisco names ISR4351/K9 as the direct non-C1 replacement PID.

Receiving gate

Match PID and serial; inventory NIM/SM modules, memory, power supply, IOS XE, boot variables and licenses. Compare C1-CISCO4321/K9 only if its lower expansion and throughput envelope fits the design.

Official Cisco sources: exact Cisco ONE PID and lifecycle table; ISR4351 hardware and performance data.