Cisco Systems ISR4321/K9 Integrated Services Router

The Cisco ISR4321/K9 Integrated Services Router is a rack-mountable Cisco ISR 4000 Series enterprise router that delivers secure WAN connectivity, advanced routing, and integrated network services for branch offices. It provides 2 Gigabit Ethernet WAN ports and 2 Gigabit Ethernet LAN ports, with base performance up to 50 Mbps (upgradable by license), and two Network Interface Module (NIM) slots for modular expansion. The unit includes two USB 3.0 ports and console access via both RJ-45 and Mini-USB ports, supporting secure VPN, firewall, and other advanced security services. VPN support covers IPsec VPN and SSL VPN, enabling secure connections between headquarters and remote sites. Management is via CLI, SNMP, and Cisco Configuration Professional. The router is designed in a compact form factor for rack-mount deployments and uses an external AC power adapter. Common replacements in the Cisco ISR lineup include ISR4331/K9, ISR4351/K9, and C1111-8P. This model is commonly installed in corporate branch offices, distributed enterprise networks, and WAN edge infrastructures where reliable routing and secure communication are required.