WS-C3850-24S-E Cisco Catalyst 3850 Switch 24 Ports Ethernet

Cisco Catalyst WS-C3850-24S-E Layer 3 Switch Overview

The Cisco Catalyst WS-C3850-24S-E is a high-performance managed Layer 3 switch designed for enterprise-grade networks. It delivers advanced routing, superior scalability, and robust security, making it an ideal choice for data centers, campus networks, and growing business infrastructures. Equipped with 24 Gigabit SFP ports, this switch ensures reliable, high-speed fiber connectivity with exceptional traffic handling.

General Product Specifications

Manufacturer and Model Details

• Brand: Cisco
• Model Number: WS-C3850-24S-E
• Device Category: Managed Layer 3 Ethernet Switch
• Form Factor: Desktop or 1U Rack-Mountable
• Stackable Design: Yes, supports high-speed stacking

Port Configuration

• 24 x Gigabit Ethernet SFP ports
• Optimized for fiber-based network deployments
• Auto-negotiation for seamless connectivity

Performance and Switching Capacity

High-Speed Data Processing

• Switching Throughput: 92 Gbps
• Forwarding Rate: 68.4 Million Packets Per Second (Mpps)
• Stacking Bandwidth: Up to 480 Gbps with Cisco StackWise-480

Scalability and Network Capacity

• IPv4 Routing Table: Up to 24,000 routes
• NetFlow Entries: 24,000
• Switched Virtual Interfaces (SVIs): Up to 1,000
• MAC Address Table: 32,000 entries
• Jumbo Frame Support: Up to 9,198 bytes

Advanced Routing and Protocol Support

Layer 3 Routing Capabilities

• BGP-4, IS-IS, RIP v1 and v2
• EIGRP and EIGRP for IPv6
• OSPFv3 for IPv6 routing
• PIM-SM and PIM-SSM multicast routing
• RIPng support

Enterprise Networking Features

Security, Control, and Optimization

• VLAN tagging and trunking support
• Access Control Lists (ACL) for traffic filtering
• DHCP Snooping and Dynamic ARP Inspection (DAI)
• RADIUS authentication support
• VRF-Lite for network segmentation

Spanning Tree and Link Management

• Rapid Spanning Tree Protocol (RSTP)
• Multiple Spanning Tree Protocol (MSTP)
• Per-VLAN Rapid Spanning Tree Plus (PVRST+)
• STP Root Guard and Uni-Directional Link Detection (UDLD)

Traffic Optimization and QoS

• Advanced Quality of Service (QoS)
• Layer 3 load balancing
• Shaped Round Robin (SRR) scheduling
• Flexible NetFlow (FNF) analytics

Energy Efficiency and Cisco Technologies

• Energy Efficient Ethernet (EEE)
• Cisco StackWise-480 Technology
• Cisco StackPower Technology
• Remote SPAN (RSPAN) for traffic analysis

Industry Standards and Compliance

• IEEE 802.3, 802.3u, 802.3z, and 802.3ab Ethernet standards
• IEEE 802.1D, 802.1Q, 802.1P, 802.1W, and 802.1S
• IEEE 802.1X for network access control
• IEEE 802.3ad (LACP) for link aggregation

Unleashing Network Performance: The Cisco Catalyst 3850

In the demanding landscape of modern enterprise networking, the convergence of wired and wireless access, the proliferation of bandwidth-intensive applications, and the need for intelligent policy enforcement demand a unified, robust, and scalable switching solution. The Cisco Catalyst WS-C3850-24S-E Managed Layer 3 Switch stands as a cornerstone of this evolved architecture. More than just a traditional access or distribution switch, the Catalyst 3850 series introduced the groundbreaking concept of Unified Access, seamlessly integrating wired switching, wireless LAN controller functionality, and advanced application visibility into a single, resilient platform. The 24S-E model, with its 24 dedicated Gigabit SFP ports, is engineered for high-density, fiber-optic connectivity at the network edge or core, offering unparalleled flexibility, performance, and security for medium to large-scale deployments.

Architectural Philosophy: The Power of Convergence

The Catalyst 3850 was designed to break down the operational and architectural silos between separate wired and wireless networks. By embedding a wireless LAN controller within the switch stack, it creates a single point of management, policy, and troubleshooting for all connected devices—whether they use an Ethernet cable or a Wi-Fi radio. This convergence simplifies network design, reduces total cost of ownership, and ensures a consistent user experience regardless of the access medium.

StackWise-480 Technology: Building Resilient Fabrics

At the heart of the Catalyst 3850's scalability is Cisco's innovative StackWise-480 technology. This allows up to nine individual 3850 switches to be logically bonded into a single, virtual switching unit.

Operational Simplicity and High Availability

The entire stack is managed as one entity with a single IP address, one routing table, and unified configuration. This drastically reduces management overhead. From a resilience perspective, StackWise-480 provides sub-second failover. If the master switch in a stack fails, a new master is elected seamlessly, minimizing network disruption and ensuring business continuity.

Scalable Performance with Cross-Stack EtherChannel

The stacking links operate at a robust 480 Gbps, forming a high-bandwidth backplane for inter-switch communication. This enables powerful features like Cross-Stack EtherChannel, allowing a single logical link (EtherChannel) to be formed using ports distributed across multiple physical switches in the stack. This eliminates single points of failure for uplinks and server connections, maximizing bandwidth utilization and availability.

Deep Dive: WS-C3850-24S-E Specifications and Deployment

The "24S" designation is key to understanding this model's role. It is built for environments where fiber-optic connectivity is paramount, such as connecting to other switches in a campus backbone, linking to servers in a data center, or providing long-distance uplinks across a building or between buildings.

Port Configuration and Flexibility

The switch provides 24 fixed Gigabit SFP (Small Form-factor Pluggable) ports. These ports support a vast array of Cisco SFP modules, allowing network architects to choose the exact transceiver needed for the task.

Choosing the Right SFP Module

For short-range, intra-building connections, 1000BASE-SX SFP modules using multimode fiber (MMF) are typical. For longer distances, such as between campuses, 1000BASE-LX/LH modules over single-mode fiber (SMF) can span up to 10 kilometers or more. This flexibility makes the 24S-E an ideal aggregation point for fiber-rich networks.

Network Module Uplinks

Beyond the 24 fixed SFP ports, the switch includes a network module slot. This slot can be populated with optional modules to add higher-speed uplinks, such as 10 Gigabit Ethernet (via SFP+ ports) or 40 Gigabit Ethernet (via QSFP+), future-proofing the investment and ensuring the switch can handle increasing backbone traffic.

Hardware and Software Feature Set

The "-E" suffix in WS-C3850-24S-E denotes the IP Services (Enterprise) feature set. This is the most comprehensive software image, unlocking full Layer 3 routing capabilities and advanced security features.

Comprehensive Layer 3 Routing

With the IP Services image, the switch functions as a full-fledged router, supporting static routing, RIP, OSPF, EIGRP, and BGP for enterprise-scale routing. It also supports advanced features like Policy-Based Routing (PBR), Multicast routing (PIM), and IPv6 in both hardware and software.

Enhanced Security and QoS

The security suite is extensive, including IEEE 802.1X for network access control, MACsec encryption for hop-by-hop data confidentiality, and Cisco TrustSec for software-defined segmentation. For quality of service (QoS), it offers deep buffer memory and advanced classification and marking capabilities to ensure voice, video, and critical data traffic are prioritized appropriately.

Intelligent Network Services and Application Visibility

The Catalyst 3850 goes beyond basic connectivity to provide deep insights and control over the applications running on the network.

Cisco Application Visibility and Control (AVC)

By integrating Network-Based Application Recognition (NBAR2), the switch can identify over a thousand applications, from business tools like WebEx and Salesforce to consumer streaming and social media. This visibility allows IT administrators to create precise policies to block, limit, or prioritize application traffic, optimizing bandwidth and enforcing acceptable use policies.

Energy Efficiency and PoE Capabilities (on Other Models)

While the 24S-E model does not provide Power over Ethernet (its sibling UPOE models do), it is built with Cisco's EnergyWise technology. This framework allows for monitoring and management of power consumption not just of the switch itself, but of connected devices, enabling proactive energy savings across the infrastructure.

Ideal Use Cases and Deployment Scenarios

The Cisco Catalyst WS-C3850-24S-E is uniquely suited for specific roles within a hierarchical network design.

Aggregation/Layer Switch in a Fiber-Rich Campus

In a large campus or enterprise building, the 24S-E excels as an aggregation switch. Its 24 SFP ports can easily connect to dozens of access switches (like 48-port Catalyst 3850 PoE models) spread across multiple floors or wings via fiber. Its Layer 3 capabilities allow it to perform inter-VLAN routing, aggregating traffic before sending it to the core.

Core Switch for Medium-Sized Networks

For a medium-sized business or a branch office, a stacked pair of WS-C3850-24S-E switches can form a highly available and capable network core. The StackWise-480 resilience, combined with full routing protocol support and high-speed uplink options, provides a robust foundation for the entire network.

Data Center Top-of-Rack (ToR) or End-of-Row (EoR)

In server environments, the high-throughput, low-latency switching, along with the option for 10G/40G uplinks, makes it suitable for connecting racks of servers via fiber. The advanced QoS and security features ensure optimal performance and segmentation for critical applications.

Management and Ecosystem

Managing the Catalyst 3850 is versatile, catering to both CLI purists and GUI-centric administrators.

Cisco IOS XE: A Robust, Modular Operating System

The switch runs Cisco IOS XE, a modern, Linux-based operating system that retains the familiar IOS CLI while adding modularity and service separation for increased stability. This provides a consistent operational experience for network engineers already skilled in Cisco IOS.

Management Options: CLI, Web GUI, and DNA Center

For day-to-day management, administrators can use the industry-standard Cisco CLI via console, SSH, or Telnet. A built-in web-based graphical interface (GUI) offers a more visual approach for configuration and monitoring. Furthermore, the Catalyst 3850 is compatible with Cisco DNA Center for intent-based networking, enabling network-wide automation, assurance, and analytics in larger, software-defined deployments.