ISR4331-AX/K9 - Cisco 4000 Family Integrated Services Router

ISR4331-AX/K9 Application Experience Scope

ISR4331-AX/K9 is the Cisco ISR 4331 Application Experience Bundle with APP and SEC licenses. Cisco's AX definition combines IP Base, Security, advanced networking and application-experience functions; it is not merely another name for ISR4331-SEC/K9.

What AX adds to the security baseline

Cisco lists L2TPv3, BFD, MPLS, VRF and VXLAN, plus PfRv3, WAAS with AppNav, NBAR2, AVC and IP SLA. Hybrid-cloud functions include LISP, OTV, VPLS and EoMPLS, with bandwidth qualifications documented for some features. Validate the exact IOS XE release and feature license rather than assuming every historical AX capability is active.

WAAS and application deployment check

Record whether the project actually uses WAAS/AppNav, application visibility or path control. Check storage, memory, service-module needs and remote-side design before reuse; an APP license in inventory does not guarantee a complete application-acceleration deployment.

ISR4331 physical foundation

The platform provides three onboard GE interfaces, two NIM slots, one ISC slot, one SM slot, 4 GB Flash and 4 GB DRAM by default. The AX PID does not itself include every possible NIM, service module, optic, memory upgrade or voice resource.

Throughput and licensing gate

The published ISR4331 base level is 100 Mbps, with separate performance and boost licensing options. Confirm current entitlement, encrypted/application traffic and target headroom before accepting the router.

End-of-sale migration

Cisco ended sale on November 7, 2023 and names C8200-1N-4T as replacement. Security support and last hardware support are listed through November 30, 2028, while routine software-maintenance releases ended August 31, 2025.

Compare the narrower bundle

ISR4331-SEC/K9 is the SEC-only alternative when advanced application and data features are not required.

Evidence: Cisco exact AX PID and lifecycle table; Cisco AX feature and ISR4331 hardware tables.