WS-C3850-16XS-S Cisco Managed Switch - 16 Ports

Product Outline

The Cisco WS-C3850-16XS-S Catalyst 3850 is a high-performance 10 Gigabit Ethernet fiber switch designed for modern enterprise networks. Built for scalability, reliability, and advanced Layer 3 capabilities, this switch is ideal for data centers and high-speed network environments requiring robust performance and flexible management.

Main Information

General Product Details

• Brand: Cisco
• Model Number: WS-C3850-16XS-S
• Product Category: Managed Ethernet Switch
• Switch Series: Catalyst 3850

Design & Build

• Modular Design: No
• Form Factor: Rack-mountable
• Rack Compatibility: 1U
• Stacking Support: Yes

Key Features & Capabilities

High-Speed Connectivity

• Supports 10 Gigabit Ethernet for ultra-fast data transmission
• Optimized for 10GBASE-X network technology
• Designed to handle bandwidth-intensive applications efficiently

Ports & Expansion Slots

• Total Expansion Slots: 12
• Slot Type: SFP+
• Number of SFP+ Ports: 12
• Port Type: 10 Gigabit Ethernet

Media & Network Support

• Supported Media: Optical Fiber
• Ethernet Technology: 10 Gigabit Ethernet
• Ideal for fiber-based enterprise and backbone networks

Performance & Management

Advanced Layer Support

• Network Layer: Layer 3
• Enables efficient routing and advanced traffic management

Management Features

• Fully manageable for centralized network control
• Supports enterprise-grade monitoring and configuration

Power & Reliability

Power Configuration

• Power Source: Internal Power Supply
• Redundant Power Supply: Yes

Enterprise-Ready Reliability

• Ensures continuous uptime with redundant power support
• Designed for mission-critical network environments

Deep Dive: The WS-C3850-16XS-S Hardware Architecture

This specific model is engineered for bandwidth-intensive environments where fiber connectivity is paramount. Its design addresses the growing demand for 10G uplinks and server access at the edge of the network.

Port Configuration and Physical Specifications

The switch features 16 fixed 10GBASE-X SFP+ ports, providing immense flexibility for fiber connectivity. These ports support a wide array of SFP/SFP+ modules, including 1G and 10G multimode (SR) and single-mode (LR, ER, ZR) optics, as well as Twinax and Active Optical Cables (AOCs) for short-reach data center applications. This allows network architects to tailor connectivity for long-distance campus backhaul, high-speed links to servers or storage, or dense aggregation of 1G fiber access switches. The switch operates as a 1RU (Rack Unit) device, making it ideal for space-constrained racks. It is designed with front-to-back airflow, a critical feature for modern, hot/cold aisle containment in data centers and wiring closets.

Performance and Scaling Capabilities

Beneath the port panel lies a powerful switching engine. The Catalyst 3850 series is built on Cisco's UADP ASIC, delivering wire-rate Layer 2 and Layer 3 switching across all ports. The system supports extensive forwarding tables (MAC: 32K, IPv4: 24K, IPv6: 12K routes) to handle large-scale network deployments. A key strength is its StackWise-480 technology. Unlike traditional stacking, StackWise-480 creates a logical, single switch from up to 9 physical units, aggregating their backplanes into a resilient 480 Gbps ring. This creates a unified management point, simplifies operations, and enables inter-switch link aggregation for unparalleled flexibility and high availability.

Power and Cooling Design

The WS-C3850-16XS-S includes dual, hot-swappable power supply bays. It supports both AC and DC power supply units (PSUs), allowing for redundancy and compliance with diverse facility power standards. The fan tray is also modular and hot-swappable, ensuring maximum uptime and serviceability. The switch is designed for Energy Efficient Ethernet (EEE) and offers advanced power management capabilities, crucial for reducing operational expenses.

The Power of Cisco IOS XE and IP Base Software

The hardware is empowered by Cisco's robust IOS XE operating system, a modern, modular software architecture that separates control plane functions from data plane processes. This provides greater stability, in-service software upgrades (ISSU), and independent process restarts. The IP Base feature set included with this model provides a comprehensive suite of functionalities beyond basic Layer 2 switching.

Layer 3 Routing and Enhanced Services

IP Base delivers full static routing and Open Shortest Path First (OSPF) v2 & v3 for IPv4 and IPv6, Enhanced Interior Gateway Routing Protocol (EIGRP) stub routing, and Routing Information Protocol (RIP). This transforms the switch from a simple access device into a capable distribution layer switch, enabling network segmentation and efficient inter-VLAN routing. It also includes Hot Standby Router Protocol (HSRP) and Virtual Router Redundancy Protocol (VRRP) for default gateway redundancy, ensuring network resilience.

Advanced Security and QoS with IP Base

Security is integral. IP Base includes Access Control Lists (ACLs) for granular traffic filtering, Port Security to prevent MAC address flooding attacks, DHCP snooping to mitigate rogue DHCP servers, and Dynamic ARP Inspection (DAI) to guard against ARP spoofing. For quality of service, it supports advanced classification, marking, policing, shaping, and queuing based on Layer 2 through Layer 4 parameters, ensuring critical applications like voice and video receive priority across the network.

Management and Automation Features

Management is facilitated through a familiar CLI, a web-based GUI (Device Manager), and support for SNMPv3, Syslog, and NetFlow for visibility. Embedded Event Manager (EEM) scripts allow for basic automation and customized responses to network events.

Converged Access: Unifying Wired and Wireless

This is the defining characteristic of the Catalyst 3850 series. The switch hosts an embedded Wireless LAN Controller, capable of managing up to 50 access points (APs) directly. This "Switch Wireless" model brings several transformative benefits.

Simplified Network Operations

There is no longer a need for a separate physical or virtual WLC appliance for small to mid-sized deployments. The wireless configuration, policies, and software updates are managed through the same IOS XE CLI and network management tools used for the switch, drastically reducing operational complexity and cost.

Unified Policy and Visibility

With Converged Access, a user's policy (VLAN, ACL, QoS) follows them seamlessly whether they connect via an Ethernet port or a Wi-Fi network managed by the switch. This provides a consistent experience and security posture. Furthermore, network administrators gain a single view of both wired and wireless clients connected to the system, simplifying troubleshooting and network assurance.

Optimized Traffic Flow

The embedded WLC enables Flexible NetFlow with wireless context, providing deep visibility into application usage and client behavior. It also supports Local Mode and FlexConnect modes for access points, allowing for centralized or distributed data forwarding to fit different branch and campus topologies.

Ideal Deployment Scenarios for the WS-C3850-16XS-S

The combination of 10G fiber density, stacking power, and converged access makes this model exceptionally versatile for specific network roles.

High-Density 10G Access and Aggregation Layer

It is perfectly suited for aggregating multiple 1G fiber access switches (like Catalyst 2960-X) in a campus building or data hall. The 16 SFP+ ports provide ample, high-bandwidth uplinks, while StackWise-480 allows for linear scaling as the number of access switches grows. It also serves as a top-of-rack (ToR) switch for server racks requiring 10G network interface card (NIC) connectivity, especially where network virtualization or storage traffic is present.

Campus Distribution and Core for Mid-Sized Networks

In mid-sized campus or enterprise networks, a stack of WS-C3850-16XS-S switches can form a highly resilient and performant distribution or core layer. The integrated Layer 3 routing with OSPF or EIGRP, combined with the high-speed fiber links, makes it capable of routing traffic between multiple access layer blocks and to the network core or data center.

Unified Wired-Wireless Aggregation Point

For deployments requiring integrated wireless management, this switch can act as the aggregation point for both wired network segments and a fleet of Cisco Aironet access points. It consolidates functions, reducing the number of devices to purchase, power, cool, and manage, while delivering a seamless user experience.

Considerations for Fiber Infrastructure

Deploying this switch requires careful planning of the fiber plant. Considerations include the choice between multimode (OM3/OM4) for shorter distances (up to 300-400m) and single-mode (OS2) for long-distance campus links (up to 10km, 40km, or more with appropriate optics). The cost and type of SFP+ transceivers must be factored into the total solution cost.

Comparing the IP Base to Other Feature Sets

Understanding the software landscape is crucial. The Catalyst 3850 is available with three primary software tiers: LAN Base, IP Base (featured here), and IP Services.

IP Base vs. LAN Base

LAN Base is a Layer 2-only feature set. The jump to IP Base adds dynamic interior gateway routing protocols (OSPF, EIGRP stub), advanced redundancy protocols (HSRP/VRRP), and more robust security features like routing-based ACLs. For any network requiring inter-VLAN routing on the switch itself, IP Base is the minimum requirement.

IP Base vs. IP Services

IP Services is the premium tier, adding advanced routing for complex enterprise and data center networks. It includes full EIGRP and OSPF stub capabilities, Border Gateway Protocol (BGP) for enterprise WAN or data center interconnect, Protocol Independent Multicast (PIM) for efficient multicast routing, and advanced IPv6 features. The WS-C3850-16XS-S with IP Base is typically deployed where these advanced WAN/Data Center protocols are not required at the access/distribution layer.