[Codel] [PATCH net-next] fq_codel: report congestion notification at enqueue time

David Miller davem at davemloft.net
Fri Jun 29 01:29:34 EDT 2012

From: Eric Dumazet <eric.dumazet at gmail.com>
Date: Fri, 29 Jun 2012 07:24:08 +0200

> By the way, I am not sure NET_XMIT_CN is correctly used in RED.
> Or maybe my understanding of NET_XMIT_CN is wrong.
> If a the packet is dropped in enqueue(), why use NET_XMIT_CN instead of 
> This seems to mean : I dropped _this_ packet, but dont worry too much, I
> might accept other packets, so please go on...

I am pretty sure the behavior in RED is intentional.

It's a soft push back on TCP.

We're taking this path when we are unable to sucessfully ECN mark a
packet.  But our intention was to do so.

More information about the Codel mailing list