Linux Network Performance Ultimate Guide

"net.core.wmem_max: the upper limit of the TCP send buffer size. Similar to net.core.rmem_max (but for transimission)."

and then we have `net.ipv4.tcp_wmem` which bring two questions: 1. why there is no IPv6 equivalent and 2. what's the difference from `net.core.wmem_max` ?

net.core.wmem_max is a maximum value, as its name says.

net.ipv4.tcp_wmem is a triple value, with minimum, default and maximum values. The maximum given here cannot exceed the previous value.

TCP is a protocol that should be the same regardless whether it is transported by IPv4 or by IPv6.

See e.g.

https://docs.redhat.com/en/documentation/red_hat_data_grid/7...

So `net.ipv4.tcp_wmem` applies to IPv4 and IPv6? If so it's absolutely not obvious.

The three problems of computing:

0. Cache invalidation

1. Naming things

2. Off by one errors

Two problems