2 packet framer settings – Westermo MRD-3x0 User Manual

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7.2.2 Packet framer settings

The packet framer is available for all port functions that 
carry raw data (these settings are not available for the DNP3 
IP-Serial Gateway or Modbus IP-Serial Gateway). The packet 
framer allows data received from the serial port to be pack-
etised into larger blocks, reducing the overhead incurred when 
repeated packets of small sizes are sent over the network.

Figure 118: Packet framing configuration options

The following options control the packet framer:

Maximum packet size
This value determines the largest packet size to be passed to 
the network for transmission. If set to 0, the packet framer 
will be disabled and data will bypass the packet framer. The 
value chosen will depend on the application, however, the 
value should not be set higher than 1024, so the packet will fit 
a conventional Ethernet frame.

Minimum size before sending
In some applications, it may not be desirable to wait for the 
exact number of bytes specified in Maximum packet size 
before sending the packet. The value set in this field, which 
must be less than or equal to the Maximum packet size, acts 
as a send threshold. Once the accumulated byte count reaches 
this value, the packet will be sent. 

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