ISR4351/K9 ISR 4351 with 3 GE, 3 NIM, 2 SM, 4 GB FLASH, 4 GB DRAM

Cisco ISR4351/K9 - Overview

The ISR 4351 sits above the 4321 and 4331 in the ISR 4000 family, providing significantly more performance and expansion. It’s built for branch aggregation, WAN edge, and hybrid cloud connectivity, with the flexibility to add voice, security, and application services through licensing.

🔧 Key Hardware Specifications

• Form Factor: 3RU rack-mountable router
• Performance:
  • 200 Mbps default throughput
  • Upgradeable to 400 Mbps or 1 Gbps with performance licenses
• Interfaces:
  • 3x RJ45/SFP combo Gigabit Ethernet WAN/LAN ports
  • 2x NIM (Network Interface Module) slots
  • 2x SM-X (Service Module) slots
  • 1x ISC (Internal Services Card) slot
• Memory/Storage:
  • 4 GB DRAM (upgradeable to 16 GB)
  • 4 GB flash (upgradeable to 16 GB)
• Software: Runs Cisco IOS XE (modular, Linux-based OS)
• Power: Dual redundant PSU options available

🚀 Key Capabilities

• SD-WAN Ready - centralized policy, application-aware routing, and cloud integration
• Integrated Security (with SEC license) - Zone-Based Firewall, VPN (IPsec, DMVPN, FlexVPN)
• Application Visibility and Control (AVC) - deep packet inspection and traffic analytics
• WAN Optimization (with AX license) - Cisco WAAS Express for branch acceleration
• Unified Communications (with V license) - CME, SRST, SIP/H.323/MGCP gateway support
• High Expansion - dual SM-X slots for advanced services (e.g., UCS-E compute modules, switching modules)

🧩 Ideal Use Cases

• Medium to large branch offices with higher WAN throughput needs
• Regional aggregation sites consolidating multiple branch connections
• Enterprises requiring integrated voice, security, and WAN optimization in one platform
• Hybrid cloud deployments where SD-WAN and application visibility are critical