Did You Know? Choosing the Right Split Ratio When Inserting a TAP into a Network Link
Did you know that a Network TAP (Test Access Point) is an essential tool for monitoring network traffic with accuracy, especially under high-traffic conditions? Unlike SPAN ports, which may introduce limitations and packet loss, TAPs provide a reliable, passive method of capturing network data in real time.
What is a Split Ratio?
When deploying an optical TAP, the split ratio determines how much light is directed towards the monitoring device versus how much continues along the primary network path. Common split ratios include 50/50, 90/10, 80/20, 70/30, and 60/40. The first number always represents the percentage of light remaining in the network, ensuring network integrity is maintained.
For example, in a 70/30 split, 70% of the signal stays on the network, while 30% is sent to monitoring tools. Some TAPs even offer multiple outputs, such as an 80/10/10 split, enabling data to be directed to multiple monitoring devices.
Why Does Split Ratio Matter?
Selecting the right split ratio is critical for ensuring both the network and the monitoring system function properly. A higher network-side percentage helps preserve signal strength, whereas a higher tool-side percentage ensures sufficient power for packet analysis. However, fiber attenuation and insertion loss must also be accounted for in calculations.
Key Considerations for Selecting a Split Ratio
• Sensitivity of the Receiver: Different optical receivers have varying levels of sensitivity. Single-mode (SM) receivers can tolerate greater attenuation, making a 70/30 split ideal. Multi-mode (MM) receivers are less sensitive, often requiring a 50/50 or 60/40 split.
• Link Budget Calculation: The total optical power loss from connectors, fiber length, and insertion loss should be factored in to ensure the receiver gets adequate power.
• Distance Between Endpoints: Longer distances cause more attenuation, which can impact monitoring accuracy.
Common Myths About Split Ratios
Did you know that an 80/20 split is not always better for preserving network integrity? While it minimizes attenuation on the network side (-0.9 dB), it results in significant power loss on the monitoring side (-7 dB), potentially causing visibility issues. A 70/30 split (-1.5 dB network, -5 dB monitoring) often provides a better balance.
Final Recommendations
To determine the best split ratio for your network, start by calculating the loss (power) budget. If needed, minimize fiber interconnections or opt for higher sensitivity transceivers. Understanding your network’s needs, TAP location, and light budget requirements ensure optimal monitoring and network performance.
No matter what split ratio you choose, ensuring sufficient power for both network functionality and monitoring efficiency is key to achieving high-performance network observability!
Want to learn more about how choosing the right split ratio for your TAPs can help optimize your network performance? Contact us today!
