Networks with large bandwidth delay

For networks with a large bandwidth-delay, activate the TCP enhancements as specified in RFC1323.

For example, the network on an AIX® system can be configured with the no command. This command sets or displays current network attributes in the kernel. For more information, see the man page.

This table shows the network attributes with their advised values:

Table 1. Tuning of network settings
Attributes	Value	Description
`rfc1323`	`1`	Enables TCP enhancements as specified by RFC 1323, TCP Extensions for High Performance. The default is `0`. A value of `1` specifies that all TCP connections attempts to negotiate the RFC enhancements.
`sb_max`	`131072`	Specifies the maximum buffer size that is allowed for a socket. The default is 65536 bytes. From the point of view of performance recommendations, the `sb_max` value is to be twice the `TCPWindowsize` set within the IBM Storage Protect™ configuration file dsm.sys.

Set these values by issuing these commands by the root user on the appropriate system:

no -o rfc1323=1
no -o sb_max=131072

The no command does not do range checking. It accepts all values. If used incorrectly, the command might cause the system to become inoperable. These changes are lost at system restart. To permanently change the values, edit the /etc/rc.net file.