ISR4451 X/K9 Integrated Services Router with Modular 2Gbps Throughput
Product Overview
The Cisco ISR4451-X/K9 is a high-performance Integrated Services
Router (ISR) designed for large branch offices, enterprise WAN
aggregation, and hybrid cloud environments. As part of the Cisco
ISR 4000 Series, it offers modular performance up to 2 Gbps,
scalable via license upgrades. The ISR4451-X/K9 delivers converged
services, including security, voice, SD-WAN, and advanced
application hosting — all in a compact 2RU chassis.
Product Details
| Specification | Description |
|---|---|
| Product Code | ISR4451-X/K9 |
| Series | Cisco ISR 4000 Series |
| Form Factor | 2RU Rack-Mountable |
| Default Performance | 1 Gbps (boostable to 2 Gbps with license) |
| Processor | Multi-core CPU with Cisco QuantumFlow Processor |
| DRAM | 4 GB default, expandable to 16 GB |
| Flash Storage | 8 GB default, expandable to 32 GB |
| NIM Slots | 3 (for WAN, voice, or storage modules) |
| SM-X Slots | 2 (for enhanced service modules) |
| Onboard GE Ports | 4 x 1G RJ45 + 1 x 1G SFP |
| Redundant Power Supply | Supported |
| Software | Cisco IOS XE with SD-WAN and Security capabilities |
| VPN Support | IPsec, DMVPN, FlexVPN |
| Virtualization Support | Supports ISR-WAAS, KVM, UCS-E, and app containers |
Product Features
Modular performance licensing enables scalable bandwidth from 1 to 2 Gbps
Supports WAN redundancy, dual power, and high availability options
Runs Cisco IOS XE, enabling SD-WAN, Zero-Touch Provisioning, and app hosting
Integrated encryption, firewall, and deep packet inspection
Voice-ready with digital signal processors (DSPs) and telephony interfaces
Ideal for multi-service branch deployments: routing, security, voice, wireless, and SD-WAN
Flexible interface options: Ethernet, T1/E1, LTE, DSL, Fiber, voice cards
Similar Models Comparison
| Model | Performance | NIM Slots | SM-X Slots | Max Throughput | SD-WAN Capable | Ideal For |
|---|---|---|---|---|---|---|
| ISR4451-X/K9 | 1–2 Gbps | 3 | 2 | 2 Gbps | Yes | Large branch/enterprise |
| ISR4431/K9 | 500 Mbps–1 Gbps | 2 | 1 | 1 Gbps | Yes | Medium branch offices |
| ISR4351/K9 | 200–400 Mbps | 2 | 1 | 400 Mbps | Yes | Medium/small branch |
| ISR4331/K9 | 100–300 Mbps | 2 | 0 | 300 Mbps | Yes | Small branches |
Latest ISR 4000 Models Comparison
| Model | Form Factor | Performance Range | SD-WAN | Power Options | Target Use Case |
|---|---|---|---|---|---|
| ISR4451-X/K9 | 2RU | 1–2 Gbps | Yes | Dual PSU supported | Enterprise WAN, large branch |
| ISR4431/K9 | 1RU | 500M–1 Gbps | Yes | Single PSU | Medium branch office |
| ISR4351/K9 | 1RU | 200–400 Mbps | Yes | Single PSU | Voice-rich branches |
