Tuning TCP/IP performance
The IP protocol stack is
configured to maximize performance on all supported
network adapters. If desired, you can further adjust performance
parameters for each network interface using the
command as described in
``Using ifconfig to change parameters for a network card''.
This command allows you to adjust:
You can adjust systemwide TCP/IP parameters using
as described in
``Using inconfig to change global TCP/IP parameters''.
The send and receive TCP window for an interface.
These windows are used by two communicating systems to negotiate
the amount of data that can be sent before an acknowledgement is
required. The default values of these windows are set to optimize
performance on a local area network (LAN).
If you are using a high bandwidth, and high latency connection
such as a satellite link, increase the values of these parameters to
on the link.
The maximum value that you can set is 64KB.
The maximum segment size (MSS) rounding parameter.
This is a boolean value; if set to 1, TCP negotiates
the largest segment size that can be transmitted in
the maximum transmission unit of the physical network. This is
also referred to as using full frames.
If set to 0, the MSS is rounded down to the nearest power
of 2. For Ethernet, this corresponds to 1KB.
With modern Ethernet hardware, you should use full frames
to maximize the amount of data per Ethernet frame.
On older Ethernet cards with small buffers and narrow data paths,
rounding down should be selected to
enable the data in the Ethernet
frame to be moved into the card's buffer more efficiently.
Token Ring networks have a much larger MTU than Ethernet;
full frames should always be used.
This should be set for older network adapters whose small
buffers cannot handle back-to-back streams of packets.
If it is known that a substantial number of network hops will be
necessary for a packet to reach its destination, increase this
Problems with TCP/IP may be experienced if:
Other performance considerations for TCP/IP include:
The main tool for investigating the performance of TCP/IP is
as described in
``Monitoring TCP/IP performance''.
Monitoring TCP/IP performance
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003