Ethernet Network Parameters - Omron SYSMAC CJ1W-EIP21 Operation Manual

Parameter
TCP send buffer 4,096 bytes
TCP receive buffer 4,096 bytes
UDP send buffer 9,000 bytes
UDP receive buffer 9,016 bytes
FINS receive buffer 16,383 bytes
RAW send buffer 2,048 bytes
RAW receive buffer 2,048 bytes
Hold timer 75 s (See note.)
Resend timer Initial value:
Maximum value: 64 s
Continue timer Initial value:
Maximum value: 60 s
2MSL timer 60 s
IP reassemble timer 12 s
ARP timer 20 min/3 min
Window size 4,096 bytes
(initial value of max-
imum window size)
Fragment size 1,500 bytes
Segment size 1,024 bytes
TTL (Time to Live) 30
Keep-alive timer First time: 5 min
Resend: 5 s × 5 times
Note The hold time is 3 s for the UCMM service, Class 3 service, and tag data link open/close processing.
Appendix B

Ethernet Network Parameters

Value
Maximum capacity of the TCP send buffer
Maximum capacity of the TCP receive buffer
Maximum capacity of the UDP send buffer
Maximum capacity of the UDP receive buffer
Maximum capacity of the FINS receive buffer
Maximum capacity of the RAW send buffer
Maximum capacity of the RAW receive buffer
The hold timer is used for active open processing of TCP sockets.
An ETIMEDOUT error will occur if connection is not completed within
75 s.
250 ms The resend timer is used to monitor completion of reception of arrival
confirmations when transferring data via TCP sockets. If the timer setting
is exceeded before arrival confirmation is received, data is resent.
Resends are performed from the first timeout (1 s) through the 12th time-
out (64 s).
An ETIMEDOUT error will occur after the 12th timeout.
1 s The continue timer starts if preparations have been completed to send
data but the send window is too small (either 0 or too small) to send the
data and the remote node has not requested that communications be
restarted. Confirmation of the window size is requested from the remote
node when the continue timer times out. The initial value of the timer is
5 s and confirmation processing will continue consecutively with increas-
ingly longer times until the maximum time of 60 s is reached.
The 2MSL timer starts at the TCP socket that first closes the socket and
will run for 60 s in the TIME_WAIT status.
A fragmented IP packet is discarded if it cannot be reassembled within
12 seconds.
If a complete ARP table entry (with an Ethernet address) is not referred
to for 20 minutes, it is removed from the table.
An incomplete ARP table entry (no response yet returned to the ARP
request) is removed from the table after 3 minutes.
The initial value of the maximum capacity used to control the conver-
gence of TCP sockets. Actually, the node negotiates with the remote
node and uses the smaller of the values for the two nodes. The window
size will fluctuate with the available space in the TCP reception buffers of
the remote node when processing communications.
Data packets are fragmented into 1,500-byte IP packets. UDP data is
separated into 1,472-byte fragments before sending.
TCP data is separated into 1,024-byte units, unless the segments are dif-
ferent, in which case it will be separated into 536-byte units.
Decremented each time an IP router is passed.
The keep-alive timer is used for the keep-alive function with TCP connec-
tions. It must be used with UCMM, Class 3.
Description
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