Installing and Administering LAN/9000 Software

23
• TCP Socket Structure Caching
The ndd TCP parameter tcp_conn_strategy is used to enable socket
caching. This value determines how many cached data structures for
BSD TCP sockets the system keeps. This could cause the system to
speed up considerably if there are many short-lived connections on
the system.
The default value of 0 (zero) disables the feature. A value between 1
and 512 will set a minimum of 512. Any number above 512 will set
that value.
This feature was available but undocumented in HP-UX 11.00.
TCP FIN WAIT 2 Timer
The ndd TCP parameter tcp_fin_wait_2 determines how long a TCP
connection will be in FIN_WAIT_2.
Normally one end of a connection initiates the close of its end of the
connection (indicates that it has no more data to send) by sending a FIN.
When the remote TCP acknowledges the FIN, TCP goes to the
FIN_WAIT_2 state and will remain in that state until the remote TCP
sends a FIN.
If the FIN_WAIT_2 timer is used, TCP will close the connection when it
has remained in the FIN_WAIT_2 state for the length of the timer value.
The FIN_WAIT_2 timer must be used with caution because when TCP is
in the FIN_WAIT_2 state the remote is still allowed to send data. In
addition, if the remote TCP would terminate normally (it is not hung nor
terminating abnormally) and the connection is closed because of the
FIN_WAIT_2 timer, the connection may be closed prematurely.
Data may be lost if the remote sends a window update or FIN after the
local TCP has closed the connection. In this situation, the local TCP will
send a RESET. According to the TCP protocol specification, the remote
TCP should flush its receive queue when it receives the RESET. This
may cause data to be lost.
Default: 0 (indefinite)
Range: 0 - 2147483647
Units: Milliseconds
System-wide Limits for TCP and UDP Buffer Sizes
System administrators can now set system-wide limits on TCP send and