Omron SYSMAC CP Series, User Manual

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Appendices
A-110
CP2E CPU Unit Software User’s Manual(W614)
A-6-2 Ethernet Network Parameters
Parameter Value Description
Hold timer 1 8 s The hold timer is used for active open processing of TCP sockets.
An ETIMEDOUT error will occur if connection is not completed within
1
8 s.
Resend timer 3 s The resend timer is used to monitor completion of reception of arrival
confirmations when transferring data via socket services. If the timer
setting is exceeded before arrival confirmation is received, data is
resent. Resends are performed through the 12th timeout (
3 s).
An ETIMEDOUT error will occur after the 12th timeout.
2MSL timer 120 s The 2MSL timer starts at the TCP socket that first closes the socket
and will run for 120 s in the TIME_WAIT status.
ARP timer 20 min/5 s 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 5 seconds.
Window size 2,144 bytes 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 win-
dow size will fluctuate with the available space in the TCP reception
buffers of the remote node when processing communications.
Segment size
(MSS) 5 3 6 bytes TCP data is separated into 5 3 6-byte units.
TTL (Time to Live) 3 0 times Decreases 1 each time to comnunicate through the IP roater.
A-6-3 Buffer Configuration
S ocket recepiton
bu ffer
(3×4096 b yte s )
S ocket s end
bu ffer
(3×1024 b yte s )
FIN S p a cket inp u t
bu ffer
(18,432 b yte s )
FIN S /TCP
recepiton bu ffer
(4×4096 b yte s )
FIN S event bu ffer
(IN + O u t: 8×1024
b yte s )
IP p a cket inp u t
bu ffer
(8×608 b yte s ))
Comm u nic a tion s
controller
IP p a cket o u tp u t
bu ffer
(4×1600 b yte s )
Ethernet
Event