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Linus Torvalds1da177e2005-04-16 15:20:36 -07001
2There are a few network parameters that can be tuned to better match
3the kernel to your system hardware and intended usage. The defaults
4are usually a good choice for 99% of the people 99% of the time, but
5you should be aware they do exist and can be changed.
6
7The current list of parameters can be found in the files:
8
9 linux/net/TUNABLE
10 Documentation/networking/ip-sysctl.txt
11
12Some of these are accessible via the sysctl interface, and many more are
13scheduled to be added in this way. For example, some parameters related
14to Address Resolution Protocol (ARP) are very easily viewed and altered.
15
16 # cat /proc/sys/net/ipv4/arp_timeout
17 6000
18 # echo 7000 > /proc/sys/net/ipv4/arp_timeout
19 # cat /proc/sys/net/ipv4/arp_timeout
20 7000
21
22Others are already accessible via the related user space programs.
23For example, MAX_WINDOW has a default of 32 k which is a good choice for
24modern hardware, but if you have a slow (8 bit) Ethernet card and/or a slow
25machine, then this will be far too big for the card to keep up with fast
26machines transmitting on the same net, resulting in overruns and receive errors.
27A value of about 4 k would be more appropriate, which can be set via:
28
29 # route add -net 192.168.3.0 window 4096
30
31The remainder of these can only be presently changed by altering a #define
32in the related header file. This means an edit and recompile cycle.
33
34 Paul Gortmaker 06/96