C1-CISCO4321/K9 - Cisco One 4000 Family Integrated Services Router

C1-CISCO4321/K9 Exact Hardware Scope

C1-CISCO4321/K9 identifies the Cisco ONE ISR 4321 hardware order with IP Base. Cisco's end-of-life table replaces it with ISR4321/K9, confirming that this is the two-GE ISR4321 platform rather than an ISR4351 or a performance bundle.

Compact branch expansion limits

Two onboard Gigabit Ethernet interfaces, two NIM slots and one ISC slot; no service-module slot is listed for the base ISR4321. 4 GB Flash and 4 GB DRAM by default. A service-module bay is not part of the published base configuration, so module reuse must be checked against the two NIM positions and Cisco's compatibility list.

Throughput must be measured

ISR4321 base performance is 50 Mbps; FL-4320-PERF-K9 increases the documented level to 100 Mbps. Do not infer an installed performance or boost license from the Cisco ONE prefix. Capture current forwarding license, encrypted traffic, service mix and peak utilization before accepting this router for a live branch.

License ownership is not a chassis feature

The C1 order code records a Cisco ONE commercial purchase, but transferable entitlement cannot be established from the label alone. Verify Smart Account history, IOS XE registration and any IP Base, security or application rights against the exact serial number and sales record.

Past vulnerability-support date

This Cisco ONE hardware PID reached end of sale October 28, 2022; vulnerability/security support ended October 27, 2025 and last hardware support is listed as October 31, 2027. Procurement in 2026 therefore needs a migration date and explicit acceptance of the software-remediation gap.

Density alternative

Use C1-CISCO4351/K9 when additional NIM and service-module capacity or a higher performance tier is required; it is not a drop-in substitute without power and module validation.

Evidence: Cisco ISR4321 platform table and Cisco ONE exact PID lifecycle notice.