Cisco Router ISR 4000 Series ISR4431/K9 Overview
Cisco Router ISR 4000 Series ISR4431/K9 is a genuine edge and wide-area routing product from Cisco, a leading enterprise networking vendor whose Catalyst, Nexus and ISR families power campus, data-center and branch networks worldwide. Belonging to the Cisco Router ISR 4000 Series family, the ISR4431/K9 unit is built to the original factory specification, so it integrates with existing Cisco deployments predictably and behaves exactly as the platform documentation describes. In the network, it is deployed as a standalone unit or as part of a larger managed network, following the standard operating procedures of the platform.
From a specification standpoint, it offers 4 ports for client, server or uplink connectivity; aggregate capacity of 500 Mbps. These are the original factory figures for this model, giving administrators a clear picture of what the unit can deliver before it enters service. Standard mounting, cabling and management practices apply, so deployment follows the same procedures as other Cisco hardware already running in the environment.
Typical deployments include branch and campus WAN connectivity, service-provider edge and MPLS deployments, and secure remote-site interconnect. Organizations commonly source it for refresh programs, capacity expansion and spares management, keeping a tested unit on hand so outages stay short and replacements are predictable. This makes it a practical choice when original-spec hardware is required at a predictable cost.
Every unit at LinkNewNet is inspected and tested before dispatch, and stock is graded, cleaned and verified for correct operation, including port status, console access and firmware state. Our warranty coverage and responsive technical support protect the purchase after it arrives, and our team can confirm revision levels and software compatibility before you order. For volume requirements we also offer configuration checks and staged delivery options.
Contact our sales team for current availability, lead time and shipping options for the ISR4431/K9. We respond quickly with stock status and a firm quote, so you can plan the refresh or expansion with confidence.
Key Specifications
Applications
Enterprise WAN
Branch and campus routing with advanced services.
Service Provider
Edge routing for ISP and MPLS deployments.
Data Center
Interconnect core and aggregation layers reliably.
Buying a Pre-Owned ISR4431/K9
Verify the unit is tested, firmware confirmed, and condition documented. Every unit is fully tested and warranty covered. Contact our team for current stock and availability.
| Specification Category | Details |
|---|---|
| Product Name | Cisco ISR4431-V/K9 Integrated Services Router |
| Product Series | Cisco Integrated Services Router 4000 Series |
| Category | Enterprise Branch Router / Unified Communications Router |
| Manufacturer | Cisco Systems |
| Part Number | ISR4431-V/K9 |
| Form Factor | 1RU Rack-mountable |
| Bundle Type | Unified Communications (UC) Bundle |
| Architecture | Multicore CPU with separated control, data, and services planes |
| Base Throughput | 500 Mbps |
| Maximum Throughput | 1 Gbps (with performance license upgrade) |
| Onboard WAN/LAN Ports | 4 × 10/100/1000 Mbps (RJ-45 or SFP combo) |
| Network Interface Module (NIM) Slots | 3 |
| Integrated Services Card (ISC) Slot | 1 (typically used for PVDM4) |
| Voice & UC Support | Cisco Unified Communications license included |
| DSP Support | Supports PVDM4 for voice, video, and conferencing |
| Memory (DRAM) | 4 GB default (separate control & data planes) |
| Flash Storage | 8 GB default |
| Operating System | Cisco IOS XE |
| Routing Protocols | OSPF, EIGRP, BGP, RIP, IS-IS |
| Security Features | IPsec VPN, SSL VPN, hardware-accelerated encryption |
| SD-WAN Support | Cisco SD-WAN (IOS-XE based) |
| High Availability | Supports dual redundant power supplies |
| Power Supply Options | AC, DC, or PoE |
| Typical Use Cases | Large enterprise branches, UC deployments, secure WAN edge, SD-WAN environments |
| Key Advantages | Pay-as-you-grow throughput, UC-ready design, hardware-accelerated security, high availability |
ISR4431/K9 - Deployment Notes
This ISR4431/K9 router serves branch, edge, or WAN-aggregation roles depending on the interface mix and forwarding capacity of the specific SKU. Verify the interface types (GE, 10GE, SFP, WAN), memory, and module slots that this variant provides against your deployment topology.
When planning a refresh, confirm the software feature set (base, advanced, security) applicable to this SKU and the licensed throughput. Our team can confirm software state and hardware revision before dispatch.
Each ISR4431/K9 unit is inspected, tested and verified before leaving our facility, including interface operation, console access, and firmware state. Contact us for volume pricing and staged delivery options.
