/proc/sys/net/ipv4/tcp_timestamp
/proc/sys/net/ipv4/tcp_window_scaling
/proc/sys/net/ipv4/tcp_sack 

##</code><code>##

/proc/sys/net/ipv4/ip_no_pmtu_disc

##</code><code>##

/proc/sys/net/core/rmem_default      (default receive window)
/proc/sys/net/core/rmem_max          (maximum receive window)
/proc/sys/net/core/wmem_default        (default send window)
/proc/sys/net/core/wmem_max            (maximum send window)

/proc/sys/net/ipv4/tcp_rmem    (memory reserved for TCP rcv buffers)
/proc/sys/net/ipv4/tcp_wmem    (memory reserved for TCP snd buffers)

##</code><code>##

/proc/sys/net/ipv4 # cat tcp_wmem
                       4096    16384   131072

/proc/sys/net/ipv4 # cat tcp_rmem
                       4096    87380   174760