MIN_ RTO dialog

The manager ： Why? minrto want 200 ms So big ？

​ Worker ： It is as you say Linux Well ？

​ The manager ： No matter what system ,anyway,whatever, Why? minrto So big , such as 200 ms,100 ms ?

​ Worker ： Because I have to take care of Delayed ACK, Avoid unnecessary overtime retransmission . Normative theory Delayed ACK Of delay The duration is about minrto This magnitude , such as 50 ms,100 ms,200 ms.
​
The manager ： So that's it , Why minrto You can't configure every connection ？

​ Worker ： because Delayed ACK Time cannot be configured per connection , And delay The opposite end of time doesn't know .

​ The manager ： If I make sure my connection is IDC What about Nei ,RTT It's impossible to exceed 1 ms .

​ Worker ：Delayed ACK The delay How long or how long , And the receiving end does not know that the sending end is IDC Inside .

​ The manager ： Then I'll change it by force minrto by 200us Well ？

​ Worker ：rto Accuracy of ms, To reach us.

​ The manager ： If I change the implementation , The accuracy is us Well ？

​ Worker ： Does the manager have this ability ？

​ The manager ： You can have it , Change it now , Or I'll fire you .

​ Worker ： I have changed it , But you are still not allowed to configure every connection minrto, This must be determined by the overall situation , And must be consistent with Delayed ACK The magnitude is the same .

​ The manager ： this TMD Why? ？

​ Worker ： If it is completely illuminated RTT count rto, The world observes Delayed ACK Under normal conditions, it will cause frequent unnecessary timeout retransmissions , Cause internet congestion ！ Unnecessary overtime retransmission causes Internet congestion, which makes all congestion control mechanisms useless .

​ The manager ： I promise only IDC Use , Do not block the public network .

​ Worker ： If there is a configuration, someone must use it , You can't help it , People will inevitably misconfigure , Will block the Internet . You can't open this hole ！

​ The manager ： Is there any other way ？

​ Worker ： What do you want to do , Stealthily touched , Keep quiet .

​ Worker ：Google There are two options , Support us Time stamp , But without solving the fundamental problem .

​ The manager ： Then I'll ask the workers to steal it .

​ Worker ： Good luck to the manager ！

attach ：

draft-wang-tcpm-low-latency-opt-00
draft-yang-tcpm-ets-00

quite a lot “ Don't open up ” Configuration of , such as Timewait Time . Overall consideration is necessary , To ensure this overall situation ,“ What configuration can be changed at will ” It needs to be strictly controlled .

Congestion control should ensure that there is only one copy of a packet on the network , therefore “ Avoid unnecessary retransmission ” Is to strictly stop , Although you have the right to modify it at will TCP Realization , But in principle, you are against the rules . therefore , Can standards take the lead in breaking rules ？ Obviously not. .

Many private implementations ,MIN_RTO Already configurable , But this is really not open .

Zhejiang Wenzhou leather shoes wet , It's not fat when it's raining .