TCP Reno, HSTCP, STCP or Fast TCP? Or we can change the algorithm with current popular kernel?
Any recent kernel (3.14.0 is the source version I'm looking at), offers a handful of congestion control algorithms:
What you actually are using or have available depend on options chosen when the kernel has been compiled. You can see what's available with
cat /proc/sys/net/ipv4/tcp_available_congestion_control and control what is actually used by fiddling with the file
In case you have enabled kernel config inclusion in to the running kernel, you can also see what is compiled in with
zcat /proc/config.gz | grep CONG. The kernel configuration, e.g.
make menuconfig, has more detailed descriptions of each algorithm, but of course nothing beats reading the source, available in your kernel source tree under
net/ipv4/ (see files
tcp_*.c, filenames are self-explanatory).