ISR4431/K9 WAN Edge Router with NIM Expansion and IOS XE
Product Overview
The Cisco ISR4431/K9 is a modular, high-performance Integrated
Services Router in the Cisco 4000 Series, designed for mid-sized
branch offices and enterprise WAN edge deployments. It delivers
secure, application-aware services, supports modular interface
expansion, and provides up to 1 Gbps system performance, upgradable
via a performance license. The ISR4431/K9 is SD-WAN ready, powered
by Cisco IOS XE, and offers high availability, QoS, IPsec VPN, and
voice/video support with optional licenses.
Product Details
| Specification | Description |
|---|---|
| Product Code | ISR4431/K9 |
| Series | Cisco ISR 4000 Series |
| Form Factor | 1RU rack-mountable |
| Base Performance | 500 Mbps (upgradable to 1 Gbps) |
| Built-in Interfaces | 4 x 1G RJ45 (2 routed, 2 switched) |
| NIM Slots | 2 x Network Interface Module slots |
| SM Slots | 1 x Service Module slot |
| DRAM | 4 GB (expandable to 16 GB) |
| Flash Storage | 8 GB (expandable) |
| Power Supply | Optional dual redundant AC/DC |
| Software | Cisco IOS XE |
| SD-WAN Support | Yes (via IOS XE SD-WAN image) |
| Security Capabilities | IPsec VPN, ZBFW, SSL VPN (with SEC license) |
| Voice/UC Support | Available (with UC license) |
| High Availability | NSF, ISSU, redundant PSU/fans supported |
Product Features
Delivers modular routing performance up to 1 Gbps via performance-on-demand licensing
2 NIM slots and 1 SM slot for expansion with voice, WAN, LTE, or switching modules
Powered by Cisco IOS XE, enabling SD-WAN, automation, and application visibility
Integrated encryption hardware supports high-speed IPsec VPN
Voice and video capabilities enabled with optional UC license
Designed for secure, intelligent WAN edge with support for advanced routing and QoS
Supports redundant power supplies for increased branch reliability
Similar Models Comparison
| Model | Base Performance | Max Performance | NIM/SM Slots | Voice Capable | SD-WAN Ready | Form Factor |
|---|---|---|---|---|---|---|
| ISR4431/K9 | 500 Mbps | 1 Gbps | 2 NIM / 1 SM | Optional | Yes | 1RU |
| ISR4451/K9 | 1 Gbps | 2 Gbps | 3 NIM / 2 SM | Optional | Yes | 2RU |
| ISR4351/K9 | 200 Mbps | 400 Mbps | 2 NIM / 2 SM | Optional | Yes | 2RU |
| ISR4331/K9 | 100 Mbps | 300 Mbps | 2 NIM / 1 SM | Optional | Yes | 1RU |
Latest ISR 4000 Series Models Comparison
| Model | Performance Range | Ports | Target Use Case |
|---|---|---|---|
| ISR4431/K9 | 500 Mbps – 1 Gbps | 4 x 1G RJ45 | Mid-sized branches, WAN edge router |
| ISR4451-X/K9 | 1 – 2 Gbps | 4 x 1G RJ45 | Large branches needing more capacity |
| ISR4331/K9 | 100 – 300 Mbps | 4 x 1G RJ45 | Small-to-medium offices with flexibility |
