WS-X6816-10GE Cisco 16 Ports Expansion Module 10 Gigabit Ethernet

Product Overview

The Cisco WS-X6816-10GE is a high-performance 10-Gigabit Ethernet expansion module designed to enhance enterprise and data center network infrastructures. This plug-in module delivers exceptional bandwidth, scalability, and reliability, making it an ideal choice for organizations seeking advanced networking solutions.

General Product Details

• Brand: Cisco Systems
• Model Number: WS-X6816-10GE
• Product Category: Network Expansion Module

Key Capabilities and Benefits

• Supports high-speed 10-Gigabit Ethernet connectivity
• Designed for seamless network expansion
• Optimized for enterprise-grade performance and stability

Design and Architecture

Module Construction

Built as a plug-in expansion card, the Cisco WS-X6816-10GE integrates effortlessly into compatible Cisco systems. Its modular architecture ensures flexible deployment and simplified upgrades.

Form Factor

• Plug-in network module
• Engineered for compatibility with Cisco expansion slots

Port Configuration

High-Density Connectivity

• Total Ports: 16 high-speed interfaces
• Interface Type: X2 transceiver support

Performance Specifications

Data Transfer and Speed

This expansion module supports the 10-Gigabit Ethernet (10GbE) standard, enabling ultra-fast data transmission for bandwidth-intensive applications.

• Networking Protocol: 10 Gigabit Ethernet
• Maximum Throughput: Up to 10 Gbps per port

Interface and Compatibility

Network Interface Details

• 16 × X2 network interfaces
• Designed for high-speed fiber connectivity

Slot Compatibility

• Requires 1 available expansion slot
• Compatible with supported Cisco switching platforms

Architectural Overview and Positioning in the 6500/7600 Ecosystem

To fully appreciate the capabilities of the WS-X6816-10GE, one must understand its role within the modular Cisco ecosystem. It is not a standalone switch but a high-density line card designed for insertion into a supervisor-engine-driven chassis.

Key System Integration Points

The module's performance is intrinsically linked to other chassis components, primarily the backplane and the Supervisor Engine.

Backplane Bandwidth Considerations

The module features a 40 Gbps full-duplex connection to the Catalyst 6500 Series Switch Fabric. This architecture is critical, as it dictates the aggregate throughput available to all 16 ports. While each port supports 10 Gbps line rate, the shared fabric connection means that oversubscription ratios must be carefully considered during network design, especially for all-ports-at-full-capacity scenarios. This design is typical for aggregation modules, balancing cost and performance for real-world traffic patterns.

Supervisor Engine Compatibility

The WS-X6816-10GE requires a Supervisor Engine 720 or later (such as the VS-S720-10G) to operate. The Supervisor 720, with its integrated Multi-Gigabit Fabric, is essential for activating the module's fabric-enabled capabilities, allowing it to forward traffic at line rate across the fabric to other slots. Operating with earlier supervisors would severely limit performance, relegating traffic to the shared bus.

Hardware Specifications and Physical Design

The module is a double-height card occupying a single slot in the chassis. Its front panel houses 16 fixed ports, each using XENPAK-based 10GBASE-XX transceivers.

Form Factor and Environmental Specifications

As a double-height module, it consumes significant power and cooling resources within the chassis. Proper chassis power supply sizing and airflow management are prerequisites for stable operation. Early deployments often required upgrades to high-capacity AC or DC power supplies to support multiple such modules.

Port Interface Details

Each of the 16 ports is a 10-Gigabit Ethernet port that requires a separate XENPAK optical transceiver. The port type is defined by the transceiver installed (e.g., SR for short-range multi-mode, LR for long-range single-mode, ER for extended reach, and LX4 for legacy multi-mode support). This flexibility allowed network architects to tailor the module for diverse connectivity needs, from short-distance data center links (using 10GBASE-SR) to long-haul campus or metro connections (using 10GBASE-LR/ER).

Technical Capabilities and Feature Set

Beyond raw speed, the WS-X6816-10GE inherited the rich, proven software feature set of the Catalyst 6500 Series, making it far more than a simple aggregation card.

Performance and Forwarding Characteristics

Leveraging the distributed forwarding architecture of the Supervisor 720, the module can achieve high packets-per-second (PPS) rates. When operating in fabric-enabled mode, forwarding decisions are made locally on the module's dedicated ASICs, with only the payload traversing the switch fabric. This architecture minimizes latency and maximizes throughput for inter-module traffic.

Layer 2 Switching Features

The module supports the full suite of Catalyst Layer 2 features, including comprehensive IEEE 802.1Q VLAN trunking, Rapid Per-VLAN Spanning Tree Plus (RPVST+), and Multiple Spanning Tree (MST). Advanced features like Private VLANs, VLAN ACLs (VACLs), and robust broadcast/multicast storm control are fully supported, ensuring secure and stable network segmentation at 10GbE speeds.

Layer 3 Routing and Scalability

When paired with a Supervisor 720 running the appropriate Cisco IOS® Software or Cisco IOS® XE Software image, the module becomes a fully functional Layer 3 routing interface. It supports static routing and dynamic routing protocols such as OSPF, EIGRP, and BGP at wire speed. The integration with the Cisco Express Forwarding (CEF) architecture ensures efficient routing table lookups and load balancing across multiple equal-cost paths.

Advanced Services and Network Intelligence

The true value of the Catalyst platform lies in its ability to integrate services directly into the forwarding path.

Quality of Service (QoS) at 10 Gbps

The module implements sophisticated QoS policies to manage network congestion. It supports classification, marking, policing, and weighted random early detection (WRED) based on Layer 2, 3, and 4 parameters. This allows for the creation of service-level agreements (SLAs) for voice, video, and critical data traffic, even when aggregated over high-speed 10GbE links.

Security and Access Control

Security is enforced through hardware-based access control lists (ACLs). The module can apply standard and extended ACLs at line rate without impacting performance. Integration with Cisco TrustSec® for security group tagging (SGT) was possible with later software versions, providing role-based access control. Features like Dynamic ARP Inspection (DAI), IP Source Guard, and DHCP snooping help mitigate attacks at the aggregation layer.

Deployment Scenarios and Use Cases

The Cisco WS-X6816-10GE found its home in several critical network roles, often defining the performance ceiling for entire network blocks.

Data Center Server Farm Aggregation

In the mid-to-late 2000s, as servers began to ship with 10GbE network interface cards (NICs), the WS-X6816-10GE became the ideal aggregation point for high-performance server racks or blade chassis enclosures. It would aggregate traffic from top-of-rack (ToR) switches or connect directly to high-end application and database servers, providing low-latency, high-throughput access to storage and other application tiers.

Enterprise Network Core and Distribution

In large campus networks, this module served as the backbone of the network core. It provided the high-speed trunking links between distribution layer switches, consolidating traffic from hundreds of access switches. Its robust Layer 3 capabilities allowed it to function as the core routing layer, running OSPF or EIGRP to manage enterprise-wide subnets.

High-Capacity Interswitch Link (ISL) Trunking

Before the widespread adoption of 40GbE and 100GbE, bundling multiple 10GbE links via EtherChannel (Link Aggregation Control Protocol - LACP) was the primary method to create resilient, high-bandwidth logical trunks. The WS-X6816-10GE, with its 16 ports, could create massive channel groups, providing up to 160 Gbps of full-duplex bandwidth between chassis for a truly non-blocking core.