Normal Flow

Napatech Link™ Software Features

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Intel® PAC
Napatech SmartNIC
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Feature Description

Definition

A flow is regarded as normal if all of these conditions are fulfilled:

  • There is free space available in the datagram lookup table.
  • The first and last fragments are received first and last respectively.
  • The time-out period does not expire between any 2 fragments.

Fragments in a normal flow

All fragments in a normal flow are transferred to a matched fragments stream for the datagram in question.

When all fragments are in the matched fragments stream, there is no need for the application to look into different streams to reassemble the datagram.

In the following example, A1, A2 and A3 are the first, middle and last fragments respectively.

Case 1, normal flow

This table shows the sequence for a normal flow where A1 is the first fragment received and A3 the last fragment received.

Fragment Number Action
A1 The fragment is transferred to a matched fragments stream. An entry is allocated in the datagram lookup table.
A2 The fragment is transferred to the same matched fragments stream if it is received before the time-out expires. Otherwise it is transferred to the unmatched fragments stream for the datagram in question.
A3 The fragment is transferred to the same matched fragments stream if it is received before the time-out expires. Otherwise it is transferred to the unmatched fragments stream for the datagram in question. The relevant entry is removed from the lookup table, unless it is configured that only the time-out can remove the entry.