I'd never understood what the ifb4 interface was for. Here's a nice diagram from an sqm-scripts GitHub issue. Ken -------- Forwarded Message -------- Subject: Re: [tohojo/sqm-scripts] diagram needed (#125) Date: Tue, 17 Nov 2020 19:36:47 -0800 From: taggart Reply-To: tohojo/sqm-scripts To: tohojo/sqm-scripts CC: Subscribed Well it's not great, maybe something like this example Here's the dia file (gzip'd cause github) example.dia.gz I was trying to wrap my head around why ifb4 existed and how it worked. Maybe it could somehow explain that qdisc's can only work on packets leaving a device and that's the reason for the ifb4. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub , or unsubscribe .