ISR4321/K9 ISR 4321 with 2 GE, 2 NIM, 4 GB FLASH, 4 GB DRAM

Cisco ISR4321/K9 - Overview

The ISR 4321 is designed for small to medium branch offices that need secure WAN connectivity, application visibility, and modular expansion. Unlike the bundled SKUs (e.g., -SEC, -AX, -V), the /K9 base model includes only the IP Base license, with optional add-on licenses for security, voice, or application services.

🔧 Key Hardware Specifications

• Form Factor: 1RU rack-mountable router
• Performance:
  • 50 Mbps default throughput
  • Upgradeable to 100 Mbps with performance license
• Interfaces:
  • 1x RJ45/SFP combo Gigabit Ethernet WAN/LAN ports
  • 1x RJ45 Gigabit Ethernet LAN port
  • 2x NIM (Network Interface Module) slots
  • 1x ISC (Internal Services Card) slot
    
• Memory/Storage:
  • 4 GB DRAM (upgradeable to 8 GB)
  • 4 GB flash (upgradeable to 8 GB)
    
• Software: Cisco IOS XE (modular, Linux-based OS)
• Power: AC PSU (redundant PSU not supported on this model)

🚀 Key Capabilities

• SD-WAN Ready - centralized policy, application-aware routing
• Integrated Security (with add-on license) - Zone-Based Firewall, VPN (IPsec, DMVPN, FlexVPN)
• Application Visibility and Control (AVC) - deep packet inspection and traffic analytics
• Voice/UC (with add-on license) - CME, SRST, SIP/H.323/MGCP gateway support
• Modular Expansion - supports NIMs for WAN, voice, or async serial modules

🧩 Ideal Use Cases

• Branch offices needing secure WAN connectivity with modular growth
• Retail or distributed sites with lean IT staff
• Enterprises migrating from ISR G2 routers (e.g., 2900/3900 series)
• Hybrid deployments where SD-WAN and security can be added later via licensing