Extending Visibility to Cisco BiDi Links: Tapping 40G/100G Connections

As organizations scale to 40Gb and 100Gb speeds, Cisco BiDi (Bi-Directional) transceivers provide a cost-effective solution by enabling bidirectional traffic over a single multimode fiber. BiDi technology uses two wavelengths (850nm and 900nm) on the same fiber, making it ideal for network upgrades without replacing existing cabling. However, monitoring these BiDi connections presents unique challenges, requiring specialized TAPs for visibility.

Solutions for Tapping 40/100G Cisco BiDi Connections

To achieve full visibility of 40G/100G Cisco BiDi traffic, you need an optical TAP designed specifically for bidirectional communication. These TAPs split the traffic into separate paths for monitoring tools while preserving the original wavelengths.

Step-by-Step Process:

1. Select a BiDi-Compatible TAP:
   • Use an optical TAP that handles Cisco BiDi’s dual-wavelength transmission (850nm/900nm). These TAPs are designed to split the traffic without disrupting the flow, typically offering split ratios like 70/30 or 90/10 for monitoring without impacting live traffic.
   • Example: The TAPstack EN-TPSTCK4L100GBIDI from E.C.I. Networks supports 40G/100G BiDi TAP functionality, engineered to passively split bidirectional traffic for full visibility. It ensures that both transmit and receive signals are captured without disrupting live traffic, providing seamless monitoring for high-speed Cisco BiDi connections.
2. Install the TAP in the Network Path:
   • Position the TAP between the BiDi transceivers and your networking hardware (e.g., switches, routers). The TAP mirrors the traffic and forwards copies to your monitoring tool, such as a network packet broker or an intrusion detection system (IDS).
   • Ensure the TAP is installed correctly to capture both the transmit (850nm) and receive (900nm) signals.
3. Connect to Monitoring Tools:
   • The TAP outputs can be connected to a network packet broker like the ECIN's PacketMaestro, which aggregates, filters, and load-balances the captured traffic. This ensures that monitoring and security tools receive only relevant traffic, reducing the burden on these tools and improving their efficiency.
4. Optimize Split Ratios:
   • Depending on your network's sensitivity to light loss, select an appropriate split ratio (e.g., 70/30) that balances visibility with network performance. Lower split ratios (like 90/10) will send more light to the live production network.
5. Leverage Cost-Saving with RX-Only Transceivers:
   • On the network packet broker, consider using 40G/100G RX-only transceivers, like the EN-QSFP28-BIDIRX from ECI Networks, to receive the mirrored traffic. These transceivers are designed specifically for monitoring and cost less than full transceivers. By using RX-only transceivers, you can significantly reduce costs while ensuring complete visibility into your network.

Use Cases for BiDi TAPs

• Cisco ACI Deployments: Full visibility into bidirectional traffic for application-centric policies and performance optimization.
• High-Speed Edge Leaf/Spine Networks: Continuous monitoring of 40G/100G leaf-to-spine connections.
• New 40G/100G Build-Outs: Visibility in Cisco Nexus-based infrastructures with BiDi transceivers.
• Cost-Efficient Upgrades from 10Gb: Migrating to higher speeds without losing traffic monitoring capabilities.

Conclusion

Tapping Cisco BiDi links is essential for maintaining network visibility in high-speed environments. With the right BiDi TAPs, such as the TAPstack EN-TPSTCK4L100GBIDI, organizations can capture both transmit and receive signals, ensuring seamless monitoring across their upgraded networks. Additionally, using RX-only transceivers on your network packet broker can help reduce costs while still ensuring comprehensive network visibility. These TAPs and transceivers make it possible to scale network visibility without sacrificing performance or incurring high infrastructure costs.

For more information on tapping BiDi connections, reach out to E.C.I. Networks for customized solutions.