What Is the CAB-ETH-40G-5M= Cisco Cable? Compatibility, Use Cases, and Performance Explained

​​Introduction to the CAB-ETH-40G-5M=​​

The ​​CAB-ETH-40G-5M=​​ is a ​​40Gbps Ethernet Direct Attach Copper (DAC)​​ cable from Cisco, designed for high-speed, short-distance connectivity in data centers and enterprise networks. This 5-meter passive twinaxial cable simplifies spine-leaf architectures, server-to-switch links, and high-density deployments while reducing costs compared to optical solutions.

​​Technical Specifications and Design​​

• ​​Data Rate:​​ Supports ​​40 Gigabit Ethernet (40GbE)​​ for high-throughput applications.
• ​​Length:​​ 5 meters (ideal for intra-rack or adjacent rack connections).
• ​​Connector Compatibility:​​ ​​QSFP+ (Quad Small Form-Factor Pluggable)​​ interfaces, ensuring compatibility with Cisco switches like the ​​Nexus 9300/9500 series​​.
• ​​Passive Construction:​​ No signal amplification, minimizing power consumption and cost.

​​Key User Questions Answered​​

​​Q: Which Cisco devices support the CAB-ETH-40G-5M=?​​
This cable is compatible with ​​Cisco Nexus 9300/9500 switches​​, ​​UCS C-Series servers​​, and other QSFP+-enabled hardware. Always verify interface specifications to avoid mismatches.

​​Q: How does it compare to active optical cables (AOCs)?​​

• ​​Cost:​​ Passive DACs like the CAB-ETH-40G-5M= are ​​30–50% cheaper​​ than AOCs.
• ​​Distance:​​ Limited to ​​7 meters​​ for 40Gbps (vs. AOCs’ 100-meter range).
• ​​Latency:​​ Near-zero latency due to copper construction.

​​Ideal Deployment Scenarios​​

• ​​Data Center Top-of-Rack (ToR) Connectivity:​​ Link servers to switches within the same rack.
• ​​High-Frequency Trading (HFT):​​ Prioritize low-latency connections between trading servers and switches.
• ​​Cost-Sensitive Upgrades:​​ Replace legacy 10GbE infrastructure without overhauling cable management systems.

​​Advantages of Choosing the CAB-ETH-40G-5M=​​

• ​​Durability:​​ Reinforced shielding reduces electromagnetic interference (EMI) in dense environments.
• ​​Ease of Use:​​ Plug-and-play installation with no software configuration.
• ​​Energy Efficiency:​​ Passive design draws no external power.

For pricing and availability, visit the “CAB-ETH-40G-5M=” product listing.

​​Practical Considerations​​

Having deployed similar DACs in enterprise environments, I find the CAB-ETH-40G-5M= particularly valuable for balancing performance and budget. While fiber optics excel in long-distance scenarios, this cable is a no-brainer for short, high-speed links where minimizing latency and cost are priorities. Always cross-check compatibility with your switch’s QSFP+ port specifications to ensure optimal performance.