ISR4431-V/K9 with SRST and CUBE for Converged Voice and Data Networks
Product Overview
The Cisco ISR4431-V/K9 is a voice-enabled integrated services
router from the Cisco 4000 Series, tailored for enterprise branches
and service providers needing secure, converged voice and data
solutions. It includes a UC (Unified Communications/Voice) license,
supporting services like SRST (Survivable Remote Site Telephony),
CUBE (Cisco Unified Border Element), TDM voice, and SIP trunking.
With modular expansion and up to 1 Gbps performance, this platform
is ideal for IP telephony, video collaboration, and
application-aware routing.
Product Details
| Specification | Description |
|---|---|
| Product Code | ISR4431-V/K9 |
| Series | Cisco ISR 4000 Series |
| Form Factor | 1RU rack-mountable |
| Base Performance | 500 Mbps (upgradeable to 1 Gbps via license) |
| Built-in Interfaces | 4 x 1G RJ45 (2 routed, 2 switched), USB, Console |
| Voice Capability | Yes – with UC license included |
| Voice Features Supported | CUBE, SRST, TDM voice gateway, SIP/H.323 |
| 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 |
| Security Features | ZBFW, IPsec VPN, CPPr (with SEC license) |
| SD-WAN Support | Yes (IOS XE SD-WAN image) |
| High Availability | NSF, ISSU, hot-swappable fans, redundant PSU |
Product Features
Includes UC license for voice, video, and collaboration services
Supports CUBE, SRST, and TDM voice interfaces via voice modules
Modular expansion via 2 NIM and 1 SM slot for WAN, switch, LTE, or voice cards
Powered by Cisco IOS XE, enabling SD-WAN, QoS, and application visibility
Redundant power support and hardware resiliency for enterprise-grade uptime
Designed for secure, converged voice and data branch deployments
Delivers consistent user experience with support for unified communications features
Similar Models Comparison
| Model | Voice License | Max Performance | Voice Gateway | SD-WAN Ready | Form Factor |
|---|---|---|---|---|---|
| ISR4431-V/K9 | Yes | 1 Gbps | Yes | Yes | 1RU |
| ISR4451-X-AXV/K9 | Yes | 2 Gbps | Yes | Yes | 2RU |
| ISR4351-V/K9 | Yes | 400 Mbps | Yes | Yes | 2RU |
| ISR4331-V/K9 | Yes | 300 Mbps | Yes | Yes | 1RU |
Latest Voice-Enabled ISR Models Comparison
| Model | Performance | Voice Support Features | Best Use Case |
|---|---|---|---|
| ISR4431-V/K9 | 500 Mbps–1 Gbps | SRST, CUBE, SIP, TDM | Mid-size branch with voice & UC |
| ISR4351-V/K9 | 200–400 Mbps | Voice, video, conferencing | Medium branches with mixed workloads |
| ISR4331-V/K9 | 100–300 Mbps | Voice and CUBE services | Small-to-medium IP telephony offices |
