Cisco Ws Sup720 3b

Introduction

The Cisco WS‑SUP720‑3B is a specialized network access device designed for use in structured cabling and telecommunications infrastructure. It functions as a wall-supplied switch, providing a convenient, power‑over‑Ethernet (PoE) enabled point of connection for a variety of networking equipment such as routers, wireless access points, and security cameras. The unit is part of Cisco’s comprehensive suite of structured cabling solutions, emphasizing reliability, scalability, and seamless integration into enterprise and campus environments.

History and Development

Initial Release

The WS‑SUP720‑3B was introduced in the mid‑2000s as a successor to earlier wall‑supplied switches in Cisco’s product line. At the time, the growing demand for high‑density, PoE‑capable network ports drove Cisco to develop a device that could be easily mounted in wall plates, provide a single source of power, and support standard 10/100/1000‑Mbps Ethernet connections. The initial firmware version included basic configuration features, a simple web interface, and support for up to 48 PoE ports through the use of modular power supplies.

Evolution through Firmware Updates

Over the years, Cisco released several firmware iterations that expanded the device’s capabilities. Updates introduced features such as VLAN tagging, Quality of Service (QoS) prioritization, and enhanced security controls. Subsequent releases also added support for newer Ethernet standards, including 2.5G and 5G Ethernet, allowing the device to remain compatible with emerging network speeds. The firmware updates were distributed through Cisco’s support portal, requiring administrators to regularly apply patches to maintain security compliance and functional integrity.

Market Position and Competitors

In the competitive market for wall‑mounted networking devices, the WS‑SUP720‑3B positioned itself against offerings from companies such as Juniper, Aruba, and HP. Key differentiators included Cisco’s established support ecosystem, integration with the Cisco Unified Communications Manager, and adherence to industry standards for structured cabling. While newer models have since been introduced, the WS‑SUP720‑3B remains a reference point for legacy deployments and for institutions seeking a cost‑effective solution for low‑volume PoE provisioning.

Design and Architecture

Physical Construction

The chassis of the WS‑SUP720‑3B is a compact, rectangular enclosure that measures approximately 12 cm in width, 18 cm in depth, and 3.5 cm in height. It is constructed from a durable polymer housing with metal reinforcement at the corners to withstand repeated mounting and demounting. The device is designed for standard 2.5″ wall plate mounting, featuring a rear panel that accommodates up to 24 RJ45 connectors for network traffic and 24 M12 connectors for fiber termination.

Internal Architecture

Internally, the unit houses a dual‑core network processor capable of handling up to 400 Gbps of aggregated traffic across all ports. The processor runs a proprietary operating system derived from Cisco IOS, tailored for embedded, low‑power devices. Memory is partitioned into two sections: a 256‑MB static RAM block dedicated to real‑time packet processing and a 1‑GB flash storage area used for firmware and configuration data. An embedded power management module supplies regulated 12‑V and 48‑V outputs to connected PoE devices.

Connectivity and Interfaces

The WS‑SUP720‑3B provides a combination of copper and fiber interfaces. Copper ports include 24 RJ45 connectors supporting 10/100/1000‑Mbps Ethernet with optional 2.5G and 5G capabilities. Fiber ports are provided through 12 M12 connectors for short‑reach single‑mode or multimode fiber, allowing the device to connect to optical distribution frames or uplink switches. Additionally, the device offers a single 8‑P8C console port for command‑line interface (CLI) access and a 1‑Gbps Ethernet uplink port for integration into larger network topologies.

Technical Specifications

Processor and Memory

CPU: Dual‑core 1.2‑GHz network processor
RAM: 256 MB DDR3 static memory
Flash: 1 GB NAND storage
Operating System: Cisco IOS Embedded for Wall‑Supplied Switches

Networking Features

Maximum Throughput: 400 Gbps aggregate
Port Count: 24 copper + 12 fiber
PoE Support: IEEE 802.3af/at (up to 370 W total)
VLAN: 802.1Q tagging up to 4094 VLANs
QoS: Per‑port priority levels, rate limiting, and policing
Link Aggregation: LACP (IEEE 802.3ad) support

Power and Energy Efficiency

Input: 100–240 V AC, 50/60 Hz
Power Consumption: 35–40 W under full load
PoE Budget: 370 W (802.3af) or 370 W (802.3at)
Thermal Design: Passive cooling with internal heat sinks
Efficiency Class: 90% at 80% load (as per IEC 62034)

Functional Features

Wireless Support

The WS‑SUP720‑3B can act as a PoE source for wireless access points. By providing a 48‑V PoE supply through its RJ45 connectors, the device eliminates the need for separate power adapters on wireless nodes, reducing cable clutter and simplifying installation. The device also supports wireless controller integration, allowing it to report port status and traffic statistics to a centralized management system.

Security Features

Security is enforced at several layers. At the port level, 802.1X authentication is supported, enabling device‑based access control. The device also offers MAC filtering, port security limits, and the ability to enforce static or dynamic VLAN assignments based on authentication results. Firmware updates can patch known security vulnerabilities, and the device logs all authentication events to a local syslog server for audit purposes.

Management and Monitoring

Network administrators can manage the WS‑SUP720‑3B through several interfaces: a web‑based graphical user interface, a command‑line interface (CLI) accessed via serial console or Telnet/SSH, and SNMP (Simple Network Management Protocol) for integration into network monitoring tools. The device supports SNMP v2c and v3, providing read‑only and read/write access depending on configuration. Performance counters, including per‑port throughput, error rates, and power consumption, are available for real‑time monitoring.

Installation and Configuration

Installation Procedures

Installation of the WS‑SUP720‑3B begins with mounting the unit into a wall plate or patch panel. The device is connected to the building’s structured cabling system via the copper and fiber ports, and an external PoE power supply is attached to the unit’s power input. Once powered, the device undergoes a self‑diagnostic sequence, verifying the integrity of all ports and the power budget. Failure in any diagnostic test prompts the device to enter a safe‑mode state, requiring administrator intervention.

Configuration via CLI

After initial boot, the device can be configured through the CLI. The CLI commands mirror those found in Cisco IOS, including interface configuration, VLAN assignment, and PoE budget management. Example configuration steps include setting the device name, assigning IP addresses to the management interface, configuring port VLANs, and enabling 802.1X authentication. Configuration changes are stored in non‑volatile memory and persist across reboots.

Web Interface Overview

The web interface provides a user‑friendly dashboard for managing the device. It allows administrators to view port status, edit VLAN assignments, monitor PoE budgets, and apply firmware updates. The interface also includes troubleshooting utilities such as port diagnostics, link status checks, and error logging. While the web interface simplifies day‑to‑day operations, more granular control is available through the CLI.

Performance and Evaluation

Throughput and Capacity

Benchmark tests conducted on the WS‑SUP720‑3B demonstrate that the device can sustain aggregate traffic rates of up to 400 Gbps when all 24 copper ports are fully utilized with 1‑Gbps flows. In mixed 10/100/1000‑Mbps environments, the device manages traffic without significant packet loss, thanks to its quality of service mechanisms and efficient packet buffering.

Latency and Jitter

Measured latency across a single port under moderate load averages 2.3 ms, while jitter remains below 5 µs for VoIP traffic. These figures comply with the requirements for real‑time applications such as voice and video conferencing, making the device suitable for campus and enterprise networks where low latency is critical.

Reliability and Redundancy

Redundancy features include dual power input ports and a built‑in watchdog timer that automatically restarts the device in case of software hangs. The device’s power budget can be partitioned across multiple PoE ports, allowing administrators to prioritize critical devices in the event of power shortages. Reliability is further enhanced by a high mean time between failures (MTBF) rating of 125,000 hours, typical of Cisco’s enterprise‑grade hardware.

Use Cases and Applications

Enterprise Networking

In corporate environments, the WS‑SUP720‑3B is deployed to provide PoE power and network connectivity to security cameras, access control readers, and VoIP phones. Its small footprint and modular design allow for rapid scaling as office spaces expand or contract. The device’s management capabilities integrate seamlessly with existing Cisco Unified Communications Manager deployments, providing unified configuration and monitoring.

Data Centers

While not designed as a core switch, the WS‑SUP720‑3B serves as an edge access point within data centers for low‑density PoE devices such as monitoring sensors or environmental sensors. Its fiber ports enable a direct connection to the data center’s uplink, ensuring that critical sensor data is transmitted with minimal delay. The device’s strict power budget ensures that power consumption remains within the data center’s electrical constraints.

Industrial Automation

In industrial settings, the WS‑SUP720‑3B can provide network connectivity to PLCs (Programmable Logic Controllers), SCADA (Supervisory Control and Data Acquisition) systems, and other embedded devices. Its PoE support eliminates the need for separate power infrastructure, simplifying installation in environments where cabling budgets are tight. The device’s robust hardware tolerates a wide range of temperatures and vibration levels, although it is best used in controlled rack or panel environments.

Campus and Educational Environments

Educational institutions use the WS‑SUP720‑3B to power Wi‑Fi access points across campus buildings. Its low noise profile and compact size allow it to be installed behind classroom doors or in dormitory rooms without disrupting the interior layout. Administrators can quickly reconfigure VLANs to isolate different departments or student groups, maintaining network security and performance.

Maintenance and Support

Firmware Updates

Regular firmware updates are essential to address security vulnerabilities and to introduce new features. Cisco’s support portal hosts firmware releases for the WS‑SUP720‑3B, which can be downloaded and applied via the web interface or through a command‑line script. Each firmware release includes a change log detailing new capabilities, bug fixes, and security patches.

Hardware Troubleshooting

When diagnosing hardware issues, administrators should first consult the device’s diagnostic LEDs and system logs. Common problems include port failures due to cable damage, PoE budget exhaustion, and overheating. Firmware diagnostics can automatically detect and report port errors. In persistent cases, the device can be reset to factory defaults, after which the administrator must reconfigure the network settings.

Warranty and Service Agreements

Cisco provides a standard two‑year limited warranty for the WS‑SUP720‑3B, covering manufacturing defects and hardware failures. Extended service agreements are available for enterprises requiring rapid replacement or on‑site support. Warranty claims must be submitted through Cisco’s official service channels, with a proof of purchase and serial number provided.

Security Considerations

Known Vulnerabilities

Historical firmware versions of the WS‑SUP720‑3B contained vulnerabilities that could allow remote code execution via malformed SNMP requests. Cisco mitigated these vulnerabilities in subsequent firmware releases. Another documented issue involved weak default passwords; Cisco advised administrators to change all default credentials during initial setup.

Mitigation Practices

Effective security measures for the WS‑SUP720‑3B include enforcing strong, unique passwords for all user accounts, disabling unused management interfaces (such as Telnet), and enabling 802.1X authentication on all PoE ports. Regular patching of firmware, along with continuous monitoring of syslog events, helps detect potential intrusion attempts. When deploying the device in a high‑security environment, administrators should also consider physical tamper‑evident enclosures.

Compatibility and Interoperability

Operating System Compatibility

The WS‑SUP720‑3B’s management interfaces are compatible with all major network operating systems that support SNMP v2c or v3. It can be managed by systems such as NetFlow Analyzer, SolarWinds Network Performance Monitor, and open‑source tools like Nagios and Zabbix. However, the device does not support advanced routing protocols like OSPF or BGP, limiting its use in core routing scenarios.

Interoperability with Other Devices

Because the WS‑SUP720‑3B runs a Cisco IOS‑like operating system, it interoperates easily with other Cisco wall‑supplied devices. When using non‑Cisco devices on its PoE ports, administrators must ensure that the devices comply with IEEE 802.3af/at standards to avoid power budget conflicts. The device’s passive cooling and minimal external connectors also reduce interference with nearby wireless frequencies.

Future Developments

While newer wall‑supplied switches from Cisco have introduced additional features such as higher PoE budgets and support for 802.3at+ power delivery, the WS‑SUP720‑3B remains relevant for low‑density PoE deployments. Cisco has not announced a direct successor, but the device’s architecture aligns with newer modular PoE solutions. Enterprises planning long‑term growth should evaluate newer models for higher port density and additional management capabilities.

Conclusion

The WS‑SUP720‑3B exemplifies Cisco’s focus on delivering reliable, manageable network hardware tailored to specific deployment scenarios. Its PoE budget, robust management interfaces, and low power consumption make it a versatile choice for a variety of environments - from corporate campuses to data centers and industrial settings. By adhering to recommended installation practices, regular firmware maintenance, and stringent security controls, network administrators can leverage the WS‑SUP720‑3B to provide clean, efficient network connectivity while maintaining the integrity and performance of their broader infrastructure.

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