ISR4431-VSEC/K9 Integrated Services Router with UC and Threat Defense
Product Overview
The Cisco ISR4431-VSEC/K9 is a fully integrated voice and security
router from the Cisco ISR 4000 Series, designed for medium-to-large
enterprise branches that require unified communications, advanced
threat protection, and SD-WAN readiness in a single device. This
model includes both Voice (UC) and Security (SEC) technology
licenses, enabling IP telephony, IPsec VPN, zone-based firewall,
application control, and TDM voice gateway functionality, with
performance scalable from 500 Mbps up to 1 Gbps via license.
Product Details
| Specification | Description |
|---|---|
| Product Code | ISR4431-VSEC/K9 |
| Series | Cisco ISR 4000 Series |
| Form Factor | 1RU Rack-Mountable |
| Default Throughput | 500 Mbps (license-upgradable to 1 Gbps) |
| Processor | Cisco QuantumFlow Processor |
| System Memory (DRAM) | 4 GB (upgradable to 16 GB) |
| Flash Storage | 8 GB (upgradable to 32 GB) |
| Integrated Interfaces | 3 x 1G RJ45 + 1 x 1G SFP |
| Network Interface Module Slots | 2 (support voice/WAN cards) |
| Service Module Slot | 1 (for enhanced features like switching, UCS-E, storage) |
| Voice DSPs | Yes (supports TDM voice, conferencing, SRST, CME) |
| Security Package | Yes (includes IPsec VPN, ZBFW, AVC, control plane protection) |
| Redundant Power Support | Optional via external RPS |
| Software | Cisco IOS XE with UC and SEC features |
| SD-WAN Support | Yes |
| Virtualization | Supports KVM, UCS-E, and container-based apps |
Product Features
Combines voice services and security functions in one platform for converged branches
Supports Cisco Unified Communications with SRST, CME, and DSP modules
Embedded IPsec VPN, zone-based firewall, and application visibility (AVC)
Performance-on-demand model: scale throughput as needed up to 1 Gbps
Full SD-WAN capabilities: segmentation, cloud on-ramp, application-aware routing
Ideal for secure and voice-rich branch environments requiring high reliability
Modular expandability with LTE, T1/E1, FXO/FXS, UCS-E compute, and more
Similar Models Comparison
| Model | Voice License | Security License | Max Throughput | SD-WAN | NIM Slots | Ideal Use Case |
|---|---|---|---|---|---|---|
| ISR4451-X-VSEC/K9 | Yes | Yes | 2 Gbps | Yes | 3 | Secure UC for large branches |
| ISR4431-VSEC/K9 | Yes | Yes | 1 Gbps | Yes | 2 | Voice + security for mid-size branches |
| ISR4351-VSEC/K9 | Yes | Yes | 400 Mbps | Yes | 2 | Voice-rich, secure small sites |
Latest ISR 4000 Series Voice + Security Models
| Model | Form Factor | Voice + Security | Max Throughput | SD-WAN Ready | Target Deployment |
|---|---|---|---|---|---|
| ISR4451-X-VSEC/K9 | 2RU | Yes | 2 Gbps | Yes | Enterprise-class branch |
| ISR4431-VSEC/K9 | 1RU | Yes | 1 Gbps | Yes | Medium enterprise branch |
| ISR4351-VSEC/K9 | 1RU | Yes | 400 Mbps | Yes | Branch sites with voice + security |
