Cisco ISR4321/K9 4321 Integrated Services Router

ISR4321/K9 Base Chassis Scope

ISR4321/K9 identifies the Cisco 4321 ISR base platform, not an application bundle such as an AX or security package. It has two onboard 10/100/1000 WAN or LAN ports, provided as two RJ-45 interfaces with one shared SFP-based interface choice, plus two Network Interface Module slots and one onboard ISC slot.

Throughput License Differences

Cisco specifies 50 Mbps aggregate throughput by default. The FL-4320-PERF-K9 performance license raises the published aggregate level to 100 Mbps, while the Boost license figure is 1.5 Gbps for aggregate CEF-only traffic. Buyers should compare these distinct measurement and licensing conditions rather than treating 1.5 Gbps as the base encrypted or services-enabled capacity.

Memory, Power and Expansion Checks

The ordering entry lists 4 GB default flash and 4 GB default DRAM. The chassis accepts two NIMs but has no enhanced service-module slot. Cisco specifies an external AC or PoE power arrangement for the 4321, no redundant power-supply option, 24 W typical draw without modules and 125 W maximum with the AC supply. Confirm NIM compatibility, software licensing, rack kit, power option and required SFPs before purchase.

• Use the exact ISR4321/K9 code when the base 4321 chassis is required; bundle suffixes represent different commercial contents.
• Document whether the deployment uses the default, performance or Boost throughput license.
• Validate each proposed NIM against the installed Cisco IOS XE release and feature set.
• Account for the external power supply and the 1RU chassis depth in the rack plan.

Cisco 4000 Family ISR official data sheet | Cisco 4321 official support page