ISR4321-V/K9 Small Office Router with TDM Gateway Support
Product Overview
The Cisco ISR4321-V/K9 is a voice-enabled integrated services
router from the Cisco ISR 4000 Series, specifically designed for
small to mid-sized branch offices requiring unified communications.
This model includes the Unified Communications (UC/Voice) license,
enabling support for VoIP, CME, SRST, and TDM gateway functions. It
delivers performance scalable from 50 Mbps to 100 Mbps, with
modular slots for WAN and voice interfaces, and is SD-WAN ready,
making it ideal for voice-rich branch deployments.
Product Details
| Specification | Description |
|---|---|
| Product Code | ISR4321-V/K9 |
| Series | Cisco ISR 4000 Series |
| Form Factor | 1RU Rack-Mountable |
| Default Throughput | 50 Mbps (license-upgradable to 100 Mbps) |
| Processor | Cisco QuantumFlow Processor |
| System Memory (DRAM) | 4 GB (upgradeable to 8 GB) |
| Flash Storage | 4 GB (upgradeable to 32 GB) |
| Integrated GE Ports | 2 x 1G RJ45 + 1 x 1G SFP |
| NIM Slots | 2 |
| SM-X Slot | None |
| Voice License Included | Yes (UC – supports CME, SRST, DSP, and VoIP) |
| Security License Included | No (requires separate SEC license for IPsec, firewall) |
| SD-WAN Capable | Yes |
| Redundant Power Supply | Not supported |
| Virtualization | Supports KVM and container-based apps |
| Software | Cisco IOS XE (modular, programmable OS) |
Product Features
UC license included for VoIP, SRST, and CME deployment scenarios
Supports TDM voice gateway (FXO/FXS, E1/T1) with voice DSP modules
Modular design with dual NIM slots for WAN and voice expansion
SD-WAN ready, enabling intelligent routing and secure multi-path WAN
Supports QoS, call survivability, and conferencing features
Ideal for voice-centric branch environments requiring compact deployment
Similar Models Comparison
| Model | Voice License | Security License | Max Throughput | SD-WAN | Ideal Use Case |
|---|---|---|---|---|---|
| ISR4331-V/K9 | Yes | No | 300 Mbps | Yes | Larger branch UC deployments |
| ISR4321-V/K9 | Yes | No | 100 Mbps | Yes | Small branch unified comms |
| ISR4321-VSEC/K9 | Yes | Yes | 100 Mbps | Yes | Small secure voice branch |
Latest Cisco ISR 4000 Voice-Enabled Models
| Model | Max Throughput | UC License | Security License | SD-WAN | Ideal Deployment Size |
|---|---|---|---|---|---|
| ISR4451-V/K9 | 2 Gbps | Yes | No | Yes | Large enterprise voice branches |
| ISR4351-V/K9 | 400 Mbps | Yes | No | Yes | Medium-size UC branches |
| ISR4331-V/K9 | 300 Mbps | Yes | No | Yes | Medium-to-small UC environments |
| ISR4321-V/K9 | 100 Mbps | Yes | No | Yes | Compact branch voice routing |
