ISR4221-SEC/K9 Secure Router for Small Branch Offices
Product Overview
The Cisco ISR4221-SEC/K9 is a security-optimized Integrated
Services Router from the Cisco 4000 Series, specifically built for
small branch offices requiring secure WAN connectivity, VPN
services, and modular expansion. With the SEC (Security) license
included, it enables features such as Zone-Based Firewall (ZBFW),
IPsec/SSL VPN, and control-plane protection. The ISR4221-SEC/K9
supports up to 35 Mbps throughput by default, expandable to 75
Mbps, making it a cost-effective and secure solution for
distributed networks.
Product Details
| Specification | Description |
|---|---|
| Product Code | ISR4221-SEC/K9 |
| Series | Cisco ISR 4000 Series |
| Form Factor | 1RU rack-mountable |
| Base Performance | 35 Mbps (upgradeable to 75 Mbps) |
| Built-in Interfaces | 2 x 1G RJ45 + 1 x 1G SFP |
| NIM Slots | 2 x Network Interface Module slots |
| DRAM | 4 GB DDR3 ECC |
| Flash Storage | 8 GB |
| USB Ports | 1 x USB 2.0 |
| Console Port | 1 x RJ45 |
| Power Supply | Fixed internal AC |
| Software | Cisco IOS XE |
| Security License Included | Yes – ZBFW, IPsec VPN, SSL VPN, CPPr |
| SD-WAN Support | Yes (with SD-WAN image) |
Product Features
Includes Security (SEC) license for enterprise-grade protection features
Enables Zone-Based Firewall, IPsec, and SSL VPN capabilities
Compact 1RU form factor ideal for space-constrained deployments
Modular architecture with 2 NIM slots for expansion (4G/LTE, voice, etc.)
Supports performance-on-demand licensing to scale as business grows
Powered by Cisco IOS XE with programmability, telemetry, and SD-WAN support
Designed for secure WAN edge connectivity in small branch environments
Similar Models Comparison
| Model | Security License | Performance Range | NIM/SM Slots | SD-WAN Ready | Form Factor |
|---|---|---|---|---|---|
| ISR4221-SEC/K9 | Yes | 35–75 Mbps | 2 / 0 | Yes | 1RU |
| ISR4321-SEC/K9 | Yes | 50–100 Mbps | 2 / 0 | Yes | 1RU |
| ISR4331-SEC/K9 | Yes | 100–300 Mbps | 2 / 1 | Yes | 1RU |
Latest ISR Security Models Comparison
| Model | Performance | Key Security Features | Target Use Case |
|---|---|---|---|
| ISR4221-SEC/K9 | 35–75 Mbps | ZBFW, IPsec, SSL VPN | Secure small branch office |
| ISR4321-SEC/K9 | 50–100 Mbps | Firewall, VPN, SD-WAN | Growing branch infrastructure |
| ISR4331-SEC/K9 | 100–300 Mbps | Enterprise-grade security | Medium branch/edge deployments |
