Understanding duplicate packets
Duplicate packets lower the statistical accuracy of analysis, increase network link saturation, and can interfere with tools. Packet deduplication removes duplicate packets and helps you avoid those situations.
 
A duplicate packet is any packet that is identical to another packet. The packet header is inspected and all fields must be identical for it to be a duplicate. However, there are some situations where the header has been modified ulghtly during the packet's journey. These situations require some fine-tuning of the deduplication settings to ignore those fields that were modified before the duplicate packet is received.