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6
2.
Ethernet Communications Interface
2.1. TCP/IP FORMAT
Each Ethernet command will consist of a TCP/IP header followed by the
required data bytes as specified in section 2.2. Figure 24 summarizes the
TCP/IP header configuration. Please note that this functionality is provided
by the software implementation of the Open Systems Interconnection
(OSI) TCP/IP protocol stack, specifically the upper 4 layers.
Byte
0
Protocol
Version
Header
Length
Type Of
Service
Total Length
4
Packet ID
Flags
Fragmentation Offset
8
Time To Live
Protocol
Header checksum
12
Source Address
16
Destination Address
20
Source Port
Destination Port
24
Sequence Number
28
Acknowledgement Number
32
Data
Offset
Reserved
Code Bits
Window
36
Checksum
Urgent Pointer
40
Data Byte 1
Data Byte 2
Data Byte 3
Data Byte N
Figure 24: Network TCP/IP datagram header