| |
| There are a few network parameters that can be tuned to better match |
| the kernel to your system hardware and intended usage. The defaults |
| are usually a good choice for 99% of the people 99% of the time, but |
| you should be aware they do exist and can be changed. |
| |
| The current list of parameters can be found in the files: |
| |
| linux/net/TUNABLE |
| Documentation/networking/ip-sysctl.txt |
| |
| Some of these are accessible via the sysctl interface, and many more are |
| scheduled to be added in this way. For example, some parameters related |
| to Address Resolution Protocol (ARP) are very easily viewed and altered. |
| |
| # cat /proc/sys/net/ipv4/arp_timeout |
| 6000 |
| # echo 7000 > /proc/sys/net/ipv4/arp_timeout |
| # cat /proc/sys/net/ipv4/arp_timeout |
| 7000 |
| |
| Others are already accessible via the related user space programs. |
| For example, MAX_WINDOW has a default of 32 k which is a good choice for |
| modern hardware, but if you have a slow (8 bit) Ethernet card and/or a slow |
| machine, then this will be far too big for the card to keep up with fast |
| machines transmitting on the same net, resulting in overruns and receive errors. |
| A value of about 4 k would be more appropriate, which can be set via: |
| |
| # route add -net 192.168.3.0 window 4096 |
| |
| The remainder of these can only be presently changed by altering a #define |
| in the related header file. This means an edit and recompile cycle. |
| |
| Paul Gortmaker 06/96 |