ISR4331-SEC/K9 Cisco 1U Router with 4GB Flash Memory

Cisco Gigabit Ethernet Router

The Cisco ISR4331-SEC/K9 is a high-performance 1U rack-mountable modular router designed for secure, scalable, and reliable networking solutions. With advanced features and robust architecture, it is ideal for enterprises seeking dependable connectivity.

General Information

• Manufacturer: Cisco
• Part Number: ISR4331-SEC/K9
• Device Type: Router

Technical Specifications

Form Factor & Build

• Rack-mountable modular design
• 1U enclosure type
• Durable and enterprise-ready

Connectivity Technology

• Wired networking
• Supports Ethernet, Fast Ethernet, and Gigabit Ethernet

Performance

• Aggregate throughput: 100 Mbps

Supported Protocols

Network & Transport Protocols

• IPSec
• PPPoE
• DHCP

Routing Protocols

• OSPF, IS-IS, RIP-1, RIP-2
• BGP, EIGRP, DVMRP
• PIM-SM, IGMPv3, GRE
• PIM-SSM, Static IPv4 & IPv6 Routing
• Policy-based Routing (PBR)
• IPv4-to-IPv6 Multicast

Remote Management Protocols

• SNMP
• RMON

Advanced Features

• Firewall protection
• VPN support including IPSec and DMVPN
• VLAN support
• Syslog integration
• IPv6 compatibility
• QoS and traffic management (CBWFQ, WRED)
• ACL support
• NetFlow and IPFIX monitoring
• Radius authentication
• Wall-mountable design

Compliance Standards

Industry Certifications

• IEEE 802.3, IEEE 802.1Q, IEEE 802.3ah
• ANSI T1.101, ITU-T G.823, ITU-T G.824
• CISPR 22 Class A, CISPR 24
• EN55024, EN55022 Class A
• FCC CFR47 Part 15
• UL 60950-1, IEC 60950-1
• CSA C22.2 No. 60950-1
• VCCI V-3, EN 61000
• KN22, KN24, CNS 13438

Memory & Storage

RAM

• 4 GB DDR3 SDRAM (installed)
• Expandable up to 16 GB

Flash Memory

• 4 GB installed
• Expandable up to 16 GB

Expansion & Connectivity

Interfaces

• 2 x RJ-45 WAN/LAN (10/100/1000)
• 1 x RJ-45 Console
• 1 x Mini-USB Type B Console
• 1 x RJ-45 Auxiliary
• 1 x USB 2.0 Type A
• 2 x SFP (Mini-GBIC)
• 1 x RJ-45 Management

Expansion Slots

• 2 x NIM slots
• 1 x ISC slot
• 1 x Enhanced Service Module (SM-X)
• 2 x DIMM 240-pin slots

Power Specifications

• Internal power supply: 250W
• Installed quantity: 1
• Voltage requirement: AC 120/230 V (50/60 Hz)

ISR4331-SEC/K9 Gigabit Ethernet Router Overview

The Cisco ISR4331-SEC/K9 1U rack-mountable router represents a powerful and scalable solution designed to meet the evolving demands of modern enterprise networking. Built as part of Cisco’s Integrated Services Router 4000 Series, this model combines high-performance routing capabilities with advanced security, application optimization, and WAN connectivity in a compact 1U form factor. Organizations seeking a balance between performance, flexibility, and cost-efficiency will find this router category particularly suitable for branch offices, medium-sized enterprises, and distributed business environments.

Equipped with 6 modular slots and 4GB of flash memory, the ISR4331-SEC/K9 enables seamless integration of additional interfaces and services without compromising system stability. Its architecture is optimized for intelligent network management, allowing businesses to deploy secure and resilient infrastructures capable of supporting cloud applications, voice communications, and data-intensive workloads.

Architecture and Design Philosophy

Compact 1U Rack-Mountable Form Factor

The 1U rack-mountable design of the Cisco ISR4331-SEC/K9 makes it ideal for environments where space efficiency is critical. Data centers and network closets benefit from its streamlined physical footprint, allowing multiple units to be installed within standard racks without excessive spatial demands. Despite its compact size, the router does not compromise on performance or expandability, making it a practical solution for both centralized and distributed network infrastructures.

Modular Expansion Capabilities

One of the defining characteristics of this router category is its modularity. With six available slots, the ISR4331-SEC/K9 supports a wide range of interface cards, including WAN interface cards (WICs), network interface modules (NIMs), and service modules. This flexibility allows organizations to customize the router based on specific requirements, such as additional Ethernet ports, serial connections, or advanced service modules for security and application optimization.

Scalable Network Growth

As businesses grow, their networking needs evolve. The modular design ensures that organizations can expand their network capabilities without replacing the entire router. Instead, they can simply add or upgrade modules, thereby extending the lifecycle of the device and reducing long-term capital expenditure.

Key and Processing Capabilities

Multi-Core CPU Architecture

The Cisco ISR4331-SEC/K9 is powered by a multi-core CPU architecture designed to handle concurrent networking tasks efficiently. This architecture enables the router to process routing, security, and application services simultaneously, ensuring optimal performance even under heavy workloads.

Throughput and Performance Licensing

This router category features a flexible performance licensing model that allows organizations to scale throughput based on their requirements. The base performance can be upgraded with licenses to achieve higher throughput levels, ensuring that the router can handle increased traffic as business demands grow.

Memory and Storage Specifications

4GB Flash Memory Configuration

The inclusion of 4GB flash memory provides sufficient storage for system files, configurations, and software updates. This capacity ensures that the router can support advanced features and services without requiring frequent upgrades.

Expandable Memory Options

In addition to onboard flash memory, the router supports memory expansion options, allowing organizations to increase storage capacity as needed. This flexibility is particularly useful for environments that require extensive logging, monitoring, or application hosting capabilities.

WAN and LAN Connectivity Options

Versatile Interface Support

The ISR4331-SEC/K9 supports a wide range of connectivity options, including Gigabit Ethernet interfaces, serial connections, and fiber-optic links. This versatility ensures compatibility with various network infrastructures and communication technologies.

High-Speed Data Transmission

Gigabit Ethernet ports enable high-speed data transfer, ensuring efficient communication between network devices. This is essential for organizations that rely on fast and reliable connectivity for their operations.

Integration with Legacy Systems

The router’s support for multiple interface types allows seamless integration with legacy systems, ensuring that organizations can transition to modern networking technologies without abandoning existing infrastructure.

Enhanced Network Flexibility

The ability to support multiple connectivity options provides organizations with greater flexibility in designing their network architecture. This adaptability ensures that the router can meet diverse networking requirements.

Quality of Service (QoS) Mechanisms

QoS features enable administrators to allocate bandwidth based on application requirements, ensuring consistent performance for latency-sensitive applications. This is particularly important for voice and video communications.

Improved User Experience

By prioritizing critical traffic, the router enhances the overall user experience, reducing delays and ensuring smooth operation of essential applications.

Cloud Integration and SD-WAN Capabilities

Cloud-Ready Architecture

The ISR4331-SEC/K9 is designed to support cloud-based applications and services, enabling organizations to leverage the benefits of cloud computing. Its architecture ensures seamless integration with public and private cloud environments.

Centralized Network Management

SD-WAN solutions provide centralized control over the network, enabling administrators to monitor and manage multiple sites from a single interface. This reduces complexity and improves operational efficiency.

Enhanced Connectivity Reliability

Dynamic path selection ensures that data is transmitted through the most efficient route, improving connectivity reliability and reducing downtime.

Remote Workforce Enablement

With support for secure VPN connections, the router enables remote employees to access corporate resources safely, supporting modern work-from-home and hybrid work models.

Multi-Site Connectivity

Organizations with multiple locations can use the router to establish secure and efficient connections between sites, ensuring consistent performance and data integrity.