Appendix 5 Differences Between The Ethernet And The Ieee802.3; Appendix 6 Icmp Protocol Supported By The Ethernet Module - Mitsubishi MELSEC-F User Manual

APPENDIX

Appendix 5 Differences between the Ethernet and the IEEE802.3

Appendix 6 ICMP Protocol Supported by the Ethernet Module

App - 19
The following shows the Ethernet header in the data link layer supported by the
Ethernet block.
Ethernet data link layer header
Ethernet frame (V 2.0) specification
IEEE802.3 (ISO/IEC8802.3) frame specification
(1) Ethernet
Destination address
(2) IEEE802.3
Destination address
The following table outlines the types of ICMP supported by the Ethernet block and the
processing performed by the Ethernet block.
ICMP Type ICMP name/description
Echo Reply
0
Result of IP packet loopback
Echo Request
8
Requests loopback of IP packet
Others
1 The Ethernet module can simultaneously receive two ICMP ECHO requests (type 8, Ping message), which are used for
existence confirmation, etc., and handles them accordingly.
When three or more ICMP ECHO requests are received at the same time, the third and succeeding requests will be
ignored.
If a response is not returned to the external device when an ICMP ECHO request is sent to the Ethernet module, send an
ICMP ECHO request to the Ethernet module again.
The Ethernet module is able to receive a maximum of 1460-byte ICMP message at one time.
Do not send an ICMP message request exceeding 1460 bytes to the Ethernet module.
Source address Type
Source address Length
Upon receiving an Echo Request, the Ethernet block sends
this message.
If destination existence confirmation is set in the buffer
memory, the Ethernet module sends this message when
attempting to confirm the existence of the target. (
Ignored by the Ethernet module. (Not supported)
MELSEC-F
Ethernet block
Data (46 to 1500 byte)
Data(46 to 1500 byte)
Processing by the Ethernet block
FCS
FCS
1
)
App - 19