Packet Truncation Flow

Packet truncation is performed at either ingress or egress before packets are forwarded to analytic tools, depending on the policy configuration. When the incoming packet length is greater than the configured truncation value, the packet is truncated to the length specified in a policy. The following figure is a conceptual representation of packet truncation.

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Packet truncation
Packet before and after truncation

The incoming packet may be terminated or truncated at ingress as ingress policy actions are applied before the egress policy actions. Egress policy match criteria are applied to the received tunneled or non-tunneled packets. The order of operations on packets upon ingress to the NPB application is as follows:

  1. Tag stripping
  2. Tag addition
  3. Forward or drop packets
  4. Tunnel termination
  5. Truncation