Knowledge Base / Rockwell In-chassis / CompactLogix / MVI69 Series / MVI69-GEC

What is the maximum message size (in bytes) that can be handled by the MVI56-GEC module?

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As a server, the module can receive a maximum packet size of 2048 bytes in one Ethernet packet. This information would then be queued up and transferred over the backplane in blocks of 400 bytes. Multiple TCP/IP packets can be received until the buffer is full at 4096 bytes. At this point messages will be lost until the information has been transferred over the backplane. Once the buffer has been cleared, the sending device must try to retransmit the data since all TCP/IP packets must be ACK'd.

As a client,the module can transmit up to 4096 bytes of information, but this will be broken into multiple TCP/IP segments, as determined by the window size of the server device and how the TCP/IP stack sends the data.

Typically, the stack will break down the packet into no greater than 1400 bytes.