WS-C3850-12X48U-E Cisco Ethernet Switch (48 Ports)

The Cisco Catalyst 3850 Series Switch

The Cisco WS-C3850-12X48U-E is a flagship model within the renowned Catalyst 3850 Series, a family of stackable, managed switches designed to unify wired and wireless network access. This particular model stands as a robust, enterprise-grade solution engineered to deliver exceptional performance, advanced security, and scalable power for demanding business environments. It integrates core switching functions with embedded wireless LAN controller capabilities, simplifying network architecture and management. Ideal for campus and branch deployments, the 3850 series is built to handle the proliferation of devices, applications, and Internet of Things (IoT) endpoints, providing a resilient and intelligent foundation for modern digital business.

Deep Dive: WS-C3850-12X48U-E Specifications & Features

This model is defined by its specific hardware configuration, designed for maximum port density and power delivery in a compact 1RU form factor. Understanding its nomenclature is key: "12X48U-E" indicates 12 10G SFP+ uplink ports and 48 Universal Power over Ethernet (UPoE) capable Ethernet ports, with the "E" denoting the enhanced feature set software license. This combination makes it a uniquely powerful aggregation or access-layer switch.

Hardware Architecture & Performance

At its core, the WS-C3850-12X48U-E is built on Cisco's UADP ASIC, delivering wire-rate Layer 2 and Layer 3 switching across all ports. It features a high-performance multi-core CPU that supports advanced services without compromising throughput.

Port Configuration and Uplinks

The switch offers a balanced and future-ready port layout:

48 x RJ-45 Ethernet Ports: All 48 downlink ports support 10/100/1000BASE-T connectivity and are capable of Cisco's Universal PoE/UPoE (up to 60W per port).
12 x SFP+ Uplink Ports: The 12 fixed SFP+ ports support 1G or 10G speeds, providing immense uplink bandwidth flexibility for connecting to network cores, storage, or other switches.

Power Subsystem

The unit comes with a Single, Integrated Power Supply (PSU). For power redundancy, a second, hot-swappable power supply (such as the PWR-C1-715WAC or similar) can be added. The total power budget supports full UPoE across a significant number of ports simultaneously, enabling the direct powering of high-wattage devices like pan-tilt-zoom cameras, thin clients, or wireless access points.

Understanding UPoE (Universal Power over Ethernet)

Beyond standard PoE (15.4W) and PoE+ (30W), UPoE delivers up to 60W per port over standard CAT5e/6 cabling. This technology, pioneered by Cisco, dramatically expands the range of devices that can be powered and managed over the network, simplifying installations and reducing infrastructure costs for endpoints like:

High-performance IEEE 802.11ac Wave 2 and Wi-Fi 6 Access PointsVideo conferencing systems and room kits
Building management systems (lighting, HVAC controllers)
Digital signage and advanced security cameras

Intelligent Software

The "-E" in the model number signifies the inclusion of the IP Services (formerly IP Base) with Enhanced Feature Set software image. This license tier unlocks the full spectrum of advanced Cisco IOS XE features, far beyond basic Layer 2 switching.

Advanced Routing & Multicast

This switch operates as a full Layer 3 router, supporting static routing, RIP, OSPF, EIGRP, and BGP for complex network segmentation and inter-VLAN routing. It also supports advanced multicast protocols like PIM-SM, PIM-SSM, and IGMP snooping for efficient media and data distribution.

Security & Policy Enforcement

Security is embedded at every layer. Key features include:

Cisco TrustSec: Enables software-defined segmentation using Security Group Tags (SGTs) for policy enforcement based on identity, not just IP address.
Advanced ACLs: Flexible, scalable access control lists for granular traffic filtering.
IEEE 802.1X & MAC Authentication Bypass (MAB): Provides robust network access control for both user and device authentication.
DHCP Snooping, IP Source Guard, Dynamic ARP Inspection (DAI): A suite of features to protect against man-in-the-middle and IP spoofing attacks.

Network Virtualization & Stacking

StackWise-480 Technology

The Catalyst 3850 uses Cisco StackWise-480, a sophisticated stacking technology that logically combines up to 9 physical switches into a single, unified management entity. The stack acts as one switch, with a single IP address and configuration file, simplifying operations. The backplane stacking ring provides a resilient 480 Gbps of bandwidth for inter-switch communication.

Benefits of StackWise-480

Simplified Management: Manage the entire stack from the master switch.
Increased Resilience: If one switch fails, the stack continues operating.
Scalable Bandwidth: Easily add ports and capacity by adding another switch to the stack.
Single Point of Control for Wireless: When acting as a wireless controller, the entire stack is managed as one wireless domain.

Ideal Deployment Scenarios & Use Cases

The WS-C3850-12X48U-E is versatile, but its specific configuration makes it exceptionally suited for certain network roles.

Campus Network Access & Aggregation Layer

In large campus or enterprise settings, this switch excels as a high-density access layer switch for wiring closets, supporting a high volume of connected users, phones, and APs. Its 10G uplinks ensure no bottleneck back to the core. It can also serve as a building or floor aggregation switch, consolidating traffic from multiple smaller access switches.

High-Power PoE Aggregation for Wireless & IoT

With its massive UPoE budget, this switch is perfect for "power-hungry" deployments. It can centrally power an entire floor of next-generation wireless access points, along with a multitude of IoT sensors, video surveillance cameras, and digital signage, all while providing the 10G uplinks necessary to handle the aggregated wireless data traffic.

Converged Access for Unified Wired & Wireless

A hallmark of the Catalyst 3850 series is its Converged Access architecture. The switch can host an embedded wireless LAN controller (WLC) for up to 50 access points (with the appropriate license). This eliminates the need for a separate physical WLC appliance, reducing cost and complexity while offering a unified policy framework for both wired and wireless clients.

Data Center Edge or Mid-Market Core

For mid-sized organizations or as a data center top-of-rack (ToR) switch, the 3850-12X48U-E provides excellent 10G server connectivity via its SFP+ ports and high-speed interconnects. Its robust Layer 3 feature set allows it to function effectively as the core switch for small to medium businesses.

Important Considerations

When procuring or deploying this switch, understanding the software licensing model is crucial.

Software Licensing Tiers

The Catalyst 3850 originally used a tiered model: LAN Base (basic L2), IP Base (entry L3), and IP Services (full L3). The "-E" model comes with IP Services pre-installed and licensed. It's important to verify the permanent license is installed and that any required feature-specific licenses (like for the wireless controller) are procured.

Smart Licensing Transition

Cisco has transitioned to a cloud-based Smart Licensing model. While this switch may have originated with traditional licensing, it may be eligible for or require conversion to Smart Licensing for ongoing software updates and support. Checking the specific software version and Cisco's licensing guides is essential.

Hardware Support & Options

Consider the operational environment:

Redundant Power: For critical deployments, adding a second hot-swappable power supply is highly recommended.
Network Modules: While this model has fixed uplinks, other 3850 models support optional network modules for additional flexibility.
Fans & Cooling: Ensure adequate airflow in the rack. The switch has reversible fan trays for front-to-back or back-to-front cooling.

Comparison & Selection

Choosing the right switch requires comparing alternatives within and outside the 3850 family.

Within the Catalyst 3850 Family

vs. WS-C3850-48T-E: The 48T model has 48 10/100/1000BASE-T ports but only 4 SFP+ uplinks. Choose the 12X48U for vastly superior uplink capacity and UPoE.
vs. WS-C3850-24XU-E: The 24XU has 24 UPoE ports and 12 SFP+ uplinks. It's a choice between higher downlink density (48 ports) vs. a slightly different form factor.
vs. Non-UPoE Models: Models ending in "L" (e.g., 48F-L) support only PoE+ (30W). Select UPoE if you need to power devices beyond 30W.

Successor Platforms: Catalyst 9000 Series

Cisco's flagship stackable switch family is now the Catalyst 9200/9300/9400 Series. The Catalyst 9300 is the direct successor to the 3850. Key considerations when deciding:

Choose Catalyst 3850 (WS-C3850-12X48U-E) for: Cost-effective procurement, proven stability, environments with existing 3850 stacks, or where the specific embedded wireless controller capability is a requirement.
Consider Catalyst 9300 (e.g., C9300-48U) for: New "greenfield" deployments, requiring the latest hardware (more throughput, MACsec, etc.), intent-based networking with DNA Center, and longer-term software support and warranty.