Cisco ISR4431/K9 Full English Product Description

Product Overview

Core Hardware Specifications

Fixed Onboard Interfaces

• 4× integrated 10/100/1000BASE-T Gigabit Ethernet composite ports: each port supports both RJ45 copper and SFP fiber transceivers, totaling 4 RJ45 + 4 SFP media options for flexible LAN/WAN uplinks
• 1× USB 2.0 Type-A port for zero-touch provisioning, external logging storage and file transfer
• Dual management console interfaces: Mini-USB Type B console + standard RJ45 serial console
• RJ45 auxiliary port for out-of-band remote access via analog modem
• Front-panel status LEDs for power, fan, temperature, port activity and PoE status

Expansion Slots

• 3× hot-swappable NIM (Network Interface Module) slots, compatible with T1/E1, xDSL, serial leased lines, 4G/5G LTE cellular gateways and PoE switch modules; all modules support Online Insertion and Removal (OIR) without chassis reboot
• 0× SM-X enhanced service module slots (ISR4431 design omits large service blade slots to maintain 1RU form factor)
• 1× internal ISC slot for dedicated hardware crypto acceleration engine

Memory Architecture (Split Plane Design, Key Upgrade over ISR43xx)

• Dedicated Data Plane DRAM: 2 GB default, fixed maximum 2 GB for wire-speed packet forwarding
• Control & Services Plane DRAM: 4 GB ECC DDR3 default, expandable up to 16 GB for routing tables, security policies and virtualized workloads
• Flash storage: 8 GB industrial-grade flash default, upgradable to maximum 32 GB for IOS XE images, local logs and NFV virtual machine storage

Throughput & Encryption Performance

• Base unlicensed aggregate multi-service throughput: 500 Mbps
• Performance license upgrade unlocks full 1 Gbps aggregate routing throughput
• Hardware-accelerated encrypted VPN throughput up to 900 Mbps for large-scale IPsec SD-WAN and remote SSL VPN traffic
• System switching fabric bandwidth exceeds 4 Gbps to eliminate forwarding bottlenecks under mixed voice, video and security workloadsCisco

Power & Physical Dimensions

• Form factor: 1 Rack Unit (1RU), standard 19-inch rack mounting brackets included
• Factory-equipped single auto-ranging AC power supply (100–240 VAC, 47–63 Hz input); supports optional dual redundant AC power supplies for high availability
• Multiple power variants available: standard AC, -48V DC telecom power, and high-wattage PoE power supply (max chassis power up to 990W with PoE PSU)
• Critical note: PoE-capable NIM modules cannot be deployed when DC power supply is installed due to limited power budget
• Physical size (H × W × D): 43.9 mm × 438.15 mm × 507.2 mm
• Operating temperature range: 0°C to 40°C (32°F–104°F) for standard office deploymentsCisco

Integrated Functional Capabilities

1. Cisco IOS XE Native SD-WAN & Intelligent WAN

2. Hardware-Accelerated K9 Enterprise Security

• AES-256 dedicated crypto engine for site-to-site IPsec VPN and remote worker SSL VPN tunnels
• Zone-Based Firewall (ZBFW), embedded Firepower Next-Generation IPS, URL filtering and malware threat prevention
• Cisco Trustworthy Systems framework: secure boot, runtime image integrity validation, FIPS 140-2 certified crypto modules
• Application Visibility and Control (AVC), Control Plane Policing (CoPP), and TrustSec group-based micro-segmentation
• Local secure internet breakout to reduce costly central data center backhaul congestion

3. Unified Communications (UC)

4. Edge NFV Virtualization

Software & Licensing

• Operating System: Modular, upgradeable Cisco IOS XE
• Base IP Base feature set preloaded: static routing, OSPF, EIGRP, basic NAT, ACL and QoS functionality
• Optional subscription add-on licenses: Performance Boost, Advanced Security, Full SD-WAN, DNA Advantage, Unified Communications
• Lifecycle status: ISR4400 series reached End-of-Sale; official Cisco TAC technical support terminates November 30, 2028. Recommended replacement model: Cisco C8300 series high-speed edge routers

Primary Deployment Use Cases

1. Large enterprise regional branch offices requiring 500 Mbps–1 Gbps multi-service throughput
2. Multi-location retail, hospitality and financial sites with converged SD-WAN, voice and integrated security
3. Campus core remote building aggregation with mixed fiber and copper uplink demands
4. Distributed branches running virtualized network functions and high-volume encrypted VPN tunnels
5. Hybrid cloud edge gateways with secure direct internet breakout and SaaS acceleration

Core Differentiators vs ISR4351/K9

1. 4 composite GE ports (4 RJ45 + 4 SFP) onboard versus 3 fixed GE ports on ISR4351
2. Higher baseline throughput: 500 Mbps base / 1 Gbps licensed vs 200 Mbps base / 400 Mbps licensed
3. Split separate data plane and control/services plane memory architecture
4. Larger default flash (8 GB vs 4 GB) and maximum expandable flash (32 GB vs 16 GB)
5. Higher maximum power budget, supporting high-density PoE expansion modules
6. Superior encrypted VPN throughput for large-scale SD-WAN deployments