Cluster I/O Protocols (CIP) Configuration and Management Manual (H06.16+, J06.05+)

ip–address}climconfig sysctl -update net.ipv4.tcp_wmem "value value
value" command.
This attribute, if changed, must be the same on all CLIMs in a Provider.
The value variables affect kernel behavior for different conditions:
• The first value sets the minimum TCP send buffer space available for a single TCP socket.
• The second value sets the default buffer space allowed for a single TCP socket.
• The third value sets the maximum TCP send buffer space.
You can also set the maximum and default sizes for socket buffers for all connections by using the
climconfig sysctl -update net.core.wmem_max value and sysctl
net.core.wmem_default value sysctl commands.
NOTE: Changes to the sysctl net.core.wmem_default parameter must be made on all
CLIMs that share the same Provider. To change the sysctl parameters:
1. Stop the CLIMs and the Provider.
2. Alter the sysctl parameters.
3. Start the CLIMs and the Provider.
If the CLIM is an Open type, reboot it.
The net.ipv4.tcp_wmem command overrides the net.core.wmem_max and
net.core.wmem_default sysctls for TCP connections.
Background
CIP supports the RFC1323 TCP high performance extensions. This includes large TCP windows to
support links with high latency or bandwidth. To make use of them, you must increase the send
and receive buffer sizes.
Programmatic Alternative
The TCP send window size can also be set on individual sockets by setting the SO_SNDBUF option.
TCPTIMEWAIT
This NonStop TCP/IPv6 attribute, which sets the minimum amount of time in seconds that a TCP
connection remains in the TIME_WAIT state, can be set by using the command:
CLIMCMD {clim-name | ip-address} climconfig sysctl -update
net.ipv4.tcp_tw_recycle value command.
If this parameter is set(1), the sockets will remain in TIME_WAIT state, which is a function of the
round trip time of the connection.
If this parameter is unset(0), the socket will remain in TIME_WAIT state for a fixed time of 60
seconds.
This attribute must be same on all CLIMs that share the same provider. If there is a change in the
sysctl parameter value, restart the CLIM.
Connections that go through TCP state aware nodes, such as firewalls, NAT devices or load
balancers may see dropped frames. The more connections there are, the more likely you will see
this issue.
UDPRECVSPACE
This NonStop TCP/IPv6 Monitor attribute, which specifies the size of the window used for receiving
data for the UDP protocol, can be set by using the climconfig sysctl -update
net.core.rmem_max value and climconfig sysctl -update
net.core.rmem_default value commands.
198 IP CIP Migration, Compatibility and Operational Differences