WS-X6904-40G-2T Cisco Catalyst 6900 Series 4-port 40G/16-port 10G Fiber Mod DFC4
Cisco WS-X6904-40G-2T Catalyst 6900 Series 4-Port 40G Module
Ultra-High-Performance 40GbE/10GbE Convergence for Core Data Centers
The Cisco WS-X6904-40G-2T is a high-performance 40 Gigabit Ethernet line card designed for enterprise core, distribution, and data center aggregation deployments. Developed by Cisco Systems, this module is part of the Catalyst 6900 Series and is engineered for the Catalyst 6500-E and 6807-XL modular switching platforms powered by the Supervisor Engine 2T (Sup2T).
This flexible Ethernet module provides four native 40 Gigabit Ethernet QSFP+ ports, which can also be configured as sixteen 10 Gigabit Ethernet ports using QSFP-to-SFP+ breakout adapters (CVR-QSFP-SFP10G). This dual-mode capability allows network administrators to deploy a mix of 40GbE uplinks and high-density 10GbE connections on the same module, making it ideal for evolving network infrastructures.
The WS-X6904-40G-2T delivers 160 Gbps of switching capacity per slot through dual 80 Gbps fabric channels, ensuring wire-rate, non-blocking performance even in high-bandwidth environments. This architecture enables organizations to support large-scale data center aggregation, campus core switching, and high-speed inter-switch connectivity without oversubscription.
A key advantage of this module is the integrated DFC4 (Distributed Forwarding Card), which performs local hardware-based packet forwarding, access control list processing, and QoS enforcement directly on the line card. This distributed architecture reduces the load on the central supervisor and significantly improves overall chassis throughput and scalability.
The module also supports advanced enterprise technologies including Virtual Switching System (VSS), allowing two physical chassis to operate as a single logical switch for enhanced redundancy and bandwidth. Additionally, Cisco TrustSec and Cisco CTS security frameworks, along with IEEE 802.1AE MACsec encryption, provide hardware-based protection for secure data transmission across the network.
With its high-bandwidth architecture, flexible 40G/10G port configuration, and distributed forwarding capabilities, the Cisco WS-X6904-40G-2T offers a powerful solution for organizations looking to scale high-speed connectivity within Catalyst 6500 and 6800 Series enterprise switching environments.
Product Specifications – Cisco WS-X6904-40G-2T 40 Gigabit Ethernet Module
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| Specification | Details |
|---|---|
| Manufacturer | Cisco Systems |
| Product Name | Cisco WS-X6904-40G-2T |
| Product Type | High-density 40G Ethernet line card |
| Product Series | Cisco Catalyst 6900 Series |
| Part Number | WS-X6904-40G-2T |
| Port Density | 4 × 40 Gigabit Ethernet ports or 16 × 10 Gigabit Ethernet ports (breakout) |
| Native Transceiver Type | QSFP+ |
| 10G Breakout Support | SFP+ using CVR-QSFP-SFP10G adapter |
| Switching Fabric Connection | 160 Gbps per slot |
| Fabric Channels | Dual 80 Gbps channels |
| Performance | Wire-rate, non-blocking switching |
| Distributed Forwarding | Integrated DFC4 (Distributed Forwarding Card) |
| Supervisor Compatibility | Requires Supervisor Engine 2T (Sup2T) |
| Chassis Compatibility | Cisco Catalyst 6500-E Series and 6807-XL |
| Forwarding Architecture | Hardware-based distributed forwarding |
| Layer Support | Layer 2 and Layer 3 switching |
| MAC Address Table | Large-scale MAC table (dependent on supervisor) |
| IPv4 Routing | Hardware-based IPv4 routing support |
| IPv6 Routing | Hardware-based IPv6 routing support |
| Access Control Lists | Hardware-based ACL processing |
| Quality of Service | Advanced QoS with hardware classification |
| Virtual Switching | Full support for Virtual Switching System (VSS) |
| Security Features | Cisco TrustSec and Cisco CTS |
| Link Encryption | IEEE 802.1AE MACsec line-rate encryption |
| Multicast Support | Hardware multicast replication |
| Latency | Optimized for high-performance core switching |
| Form Factor | Line card module for modular chassis |
| Slot Requirement | Single slot in compatible chassis |
| Deployment Layer | Core, distribution layer, data center aggregation |
| Typical Use Cases | High-speed aggregation, data center interconnect, enterprise core switching |
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FAQs:
Q1. How do I convert the 40G ports into 10G ports?
To use 10G SFP+ optics, you must install the Cisco CVR-QSFP-SFP10G adapter (Four-Ten adapter) into the QSFP slot. Each 40G port then becomes four 10G ports.
Q2. Is this module compatible with the Supervisor 720?
No. The 6900 Series modules are strictly designed for use with the Supervisor Engine 2T. They will not initialize with older supervisor models.
Q3. Can I mix 40G and 10G ports on the same module?
Yes. The module allows for "mixed mode" operation where some ports are used as 40G QSFP+ while others are converted to 10G using the adapter kits.
Q4. What type of 40G optics does this module support?
It supports a variety of QSFP+ optics, including 40GBASE-SR4 (short range), 40GBASE-LR4 (long range), and QSFP+ Direct Attach Copper (DAC) cables.
Q5. Does this module support FCoE?
Yes. When used in a supported Nexus-mode configuration or within a converged network environment, the 6900 series supports Fibre Channel over Ethernet for unified fabric deployments.
