Achieve better network performances by eliminating duplicate packets


It is common that a single packet capturing device (such as a passive prove, or any other passive tool analyzing the network performances) may be fed by copies of the same data in the same network.

Usually this happens when customers use SPAN (also referred to as Port Mirror) technology to collect multiple VLANS or multiplied ports on a switch/router to the same packet capturing device. In this case, the packet capturing tool may see the exact same IP packet multiple times even though there was no poor network performances.

One simple example is in the figure below: PC-A in VLAN 1 sends IP packets to PC-C in VLAN 2. These packets are routed at the multilayer switch. At the mirror port of the switch, we obtain both the ingress and egress copies from every packet belonging to this stream, which constitute duplicate packets. Clearly, monitoring only the ingress traffic to this port avoids data duplication, but in this case, a packet coming from PC-B to PC- A or PC-C would not be captured.

Fig.1: Simple port mirroring scheme

If all this traffic is going to the same packet capturing tool, the device may sense that data is being retransmitted by the sender and may also over-count the volume of data associated with the conversation: this will hinder effective network monitoring, since duplicate packets reduce statistical accuracy, which leads to higher perceived levels of traffic or network errors.


Remove duplicate packets at the monitoring tool level is not the solution. Monitoring tools are already overloaded in handling and processing network traffic, and they usually do not have the processing resources to handle in a proper way an additional task that is processing intensive.

Microtel Innovation has two different products that can easily solve this problem:

  • Aster A-XFE streamliner, top performances Network Packet Broker with 20X100Gbps ports, which may be used as:
    • advanced NPB which Packet Deduplication, slicing, header stripping, VLAN tagging capabilities
    • GTP Balancer with session based GTP filtering
    • One single device with both functionalities described above
  • Packet Deduplication DD1100, smart FPGA appliance specialized for Packet Deduplication, which can be used stand alone or as a Service Node with any Network Packet Brokers, for example to add this specific feature to an already installed device.