ISR4431/K9 – router – rack-mountable

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ISR4431/K9

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List Price: $7489 $2105.85
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Condition New Factory Sealed Related Quantity
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Shipping Express Shipping 2-6 Days, via DHL, FedEx, UPS, etc. Packaging weight and dimensions included:
Weight 10.5 kg
Dimensions 56 × 55 × 17 cm
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ISR4431/K9 Description

Cisco ISR4431/K9, also called ISR 4431 or Cisco 4431 router, is a high-performance branch router in the Cisco 4000 Series. It comes with four Gigabit Ethernet ports, three NIM slots, and an integrated services card slot for PVDM4 DSPs. The platform delivers 500 Mbps default throughput, scalable to 1 Gbps with performance licensing, making it ideal for larger branches requiring WAN aggregation, security, and collaboration services. With up to 16 GB DRAM, 32 GB flash, and hardware-assisted encryption, the ISR4431 ensures secure, resilient, and scalable operations in enterprise branch environments.

Product Highlights

Aggregate Throughput (Default)
RJ-45-based ports
SFP-based ports

Quick Specs

Parameter

Specification

GE Ports

4 × 10/100/1000 (RJ-45/SFP mix)

10GE Ports

None

NIM Slots

3

SM-X Slots

None

On-board PVDM/ISC

1

Aggregate Throughput

500 Mbps (base), up to 1 Gbps (licensed)

Default / Max DRAM

4 GB / 16 GB

Default / Max Flash

8 GB / 32 GB

Max Power with PoE

~250 W

Rack Units

1 RU

Weight

~6.2 kg

Key Features

High-Performance Branch Routing

Provides 500 Mbps base throughput, scalable to 1 Gbps with licensing, supporting bandwidth-heavy branch applications, cloud access, and hybrid WAN designs.

Flexible Modularity with 3 NIM Slots

Expands easily with T1/E1, xDSL, LTE, or EtherSwitch NIMs, enabling organizations to tailor WAN, voice, or LAN services to their exact needs.

Integrated Voice and Collaboration Services

Supports PVDM4 DSP modules in the onboard ISC, delivering SRST, conferencing, and transcoding for reliable unified communications.

Secure and Encrypted WAN Edge

Hardware-accelerated VPN, IPSec, and SD-WAN readiness ensure data security and policy-based segmentation across distributed branch networks.

Scalable Memory and Storage

Up to 16 GB DRAM and 32 GB flash allow greater service density, caching, and support for advanced Cisco IOS XE features without compromising performance.

Compact, Reliable, and Energy-Efficient

1RU form factor with integrated cooling, stable operation in enterprise racks, and lower energy use make it efficient for mid-to-large branch environments.

Applications Scenarios

Enterprise Branch WAN Aggregation

Suited for medium and large offices that require resilient WAN connectivity, application-aware routing, and secure VPN to connect to HQ or cloud services.

Financial, Retail, and Insurance Sectors

Delivers reliable multi-service integration, encrypted transactions, and compliance-driven VPN security, ensuring smooth operations in distributed sites.

Public Sector, Healthcare, and Education

Enables converged services at the branch edge, providing secure inter-site networking, branch telephony survivability, and modular WAN expansion for mission-critical environments.

Front View

ISR4431/K9

1

Power supply unit (PSU1)

2

LEDs

3

On/Off switch

4

Optional power supply unit (PSU0)

Chassis View

1

USB ports

2

GE ports

3

Screws to open the NIM slot

4

Router label tray

5

NIM slot (with cover)

6

Ground connection

ISR4431/K9

Product Comparison

Feature

ISR4331/K9

ISR4351/K9

ISR4431/K9

GE Ports

3

3

4

10GE Ports

–

–

–

NIM Slots

2

3

3

SM-X Slots

1

1

None

On-board PVDM/ISC

1

1

1

DRAM Default / Max

4 / 16 GB

4 / 16 GB

4 / 16 GB

Flash Default / Max

4 / 16 GB

4 / 16 GB

8 / 32 GB

Aggregate Throughput

100–300 Mbps

200–400 Mbps

500 Mbps – 1 Gbps

Max PoE with Modules

250 W

500 W

250 W

Rack Units

1 RU

2 RU

1 RU

Weight

~5.6 kg

~8.4 kg

~6.2 kg

ISR4000 Supported Modules

Module Type / Part Numbers

Supported on ISR4431/K9

Network Interface Modules (NIMs)

Yes – 3 slots

NIM-1GE-CU-SFP / NIM-2GE-CU-SFP

Yes

NIM-1MFT-T1/E1 / NIM-2MFT-T1/E1

Yes

NIM-4MFT-T1/E1 / NIM-8MFT-T1/E1

Yes

NIM-1CE1T1-PRI / NIM-2CE1T1-PRI

Yes

NIM-ES2-8 / NIM-ES2-8-P

Yes (PoE requires PoE PSU)

NIM-SSD / NIM-HDD

Yes

LTE / xDSL NIM variants

Yes

Service Modules (SM-X)

Not supported

On-board PVDM4 / ISC

Supported

SFP Modules

Supported (100M/1G SFPs)

Legacy WIC/EHWIC

Not supported

Specifications

Parameter Specification Parameter Specification
Model ISR4431 (Cisco 4000 Series ISR) Form Factor 1RU rack-mount
GE Ports 4 × 10/100/1000 10GE Ports None
NIM Slots 3 SM-X Slots None
On-board ISC 1 slot for PVDM4 DSPs USB Ports 2 × USB 2.0 Type-A, 1 × mini-USB console
Console / AUX RJ-45 console and RJ-45 auxiliary Operating System Cisco IOS XE
Default / Max DRAM 4 GB / 16 GB Default / Max Flash 8 GB / 32 GB
Aggregate Throughput 500 Mbps (base), 1 Gbps (licensed) Encryption Hardware-assisted VPN
WAN/LAN via Modules NIMs for T1/E1, serial, xDSL, LTE, EtherSwitch SFP Support 100/1000 Mbps SFPs
Power Supply AC PSU, optional DC Max PoE Budget Up to 250 W with PoE PSU
Cooling Integrated fan system Operating Temp 0–40 °C
Humidity 5%–85% non-condensing Altitude 0–10,000 ft
Dimensions (H×W×D) 1.73 × 17.25 × 19.97 in Weight ~6.2 kg
Compliance IEC/EN/UL 60950-1/62368-1, CISPR 22/24 Class A Licensing Performance, Security, UC, AppX

Get More Information

Discover unbeatable prices and fast shipping for the ISR4431/K9 Access the detailed ISR4431/K9 datasheet and ensure you’re getting the best deal with our reliable delivery service. Need assistance? Our free live chat support is here to help. For more information about the product and pricing, contact us via Live chat or email us at [email protected]

Quality Certifications

Customer Reviews

Write A Review
5.0
(3 reviews)
5 Stars
3
4 Stars
0
3 Stars
0
2 Stars
0
1 Stars
0
    Obi-Wan Kenobi
    Posted on 22/07/2024
    Verified Buyer
    5.0

    These are the routers you are looking for. Reliable and genuine.

    Infrastructure Lead
    Posted on 12/03/2024
    Verified Buyer
    5.0

    Performance license applied. Throughput handles our branch encryption easily.

    NetOps
    Posted on 15/11/2023
    Verified Buyer
    5.0

    Redundant power supplies are a plus on this model. Solid uptime.

Questions & Answers

  • What is the Cisco ISR4431/K9 used for?

    A flexible ISR 4000 for mid-size branches providing modular WAN, strong crypto, and services like CUBE, SRST, and SD-WAN with balanced cost and performance.

  • How does ISR4431 compare to ISR4351?

    ISR4431 offers more performance and expansion. Choose ISR4351 for moderate needs; step to 4431 when you anticipate growth in VPN or voice sessions.

  • Is SD-WAN available?

    Yes. It supports Cisco SD-WAN with app-aware routing, centralized templates, and analytics, or can run as a classic ISR router.

  • What are typical voice features?

    CUBE for SIP trunks, SRST for survivability, and NIMs for analog integration. QoS/LLQ keeps voice quality consistent across the WAN.

  • How to design redundancy?

    Use dual ISPs, first-hop redundancy on LAN, and optional LTE failover. Validate routing and tunnel convergence during planned tests.

  • How do I manage at scale?

    Adopt standardized templates, network automation, and streaming telemetry. The web UI helps with day-0/1 tasks.

  • Deployment scenarios?

    Retail distribution, regional offices, and campuses with mixed data, voice, and security needs.

  • Licensing tips?

    Size SD-WAN, security, and CUBE licenses to real usage; monitor capacity and adjust subscriptions.

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Resources Downloads

  • ISR4431-K9 Datasheet

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