[Bloat] Stab overhead caliculation and mpu for ingress shaping.

[Y]

Hi , all.

I set root qdisc for traffic shaping like this

egress
$tc qdisc add dev $ext_ingress root handle 1: stab overhead -4
linklayer atm mpu 60 mtu 2048 tsize 256 hfsc default 13

ingress
$tc qdisc add dev $ext root handle 1: stab overhead -4 mpu 53 linklayer
atm mtu 2048 tsize 256 hfsc default 26
($ works at script )

PPPoA WAN - modem/router - Ethernet LAN - My pc 1 interface.

engress overhead of PPPoA via ethernet is -4 and mpu 53.
This is certain.
We can think without Ethernet padding at stab.

My asking is whether that This is also correct at ingress shaping or
not?

mpu for ingress in myscript = 60.
Because of minimal ethernet packet size = 60( with padding without FCS)

oevrhead for ingress in myscript = -4.
Because I want to shape connection , so , must set speed setting * 48 /
53.

This is certain or not?

Yuta. 

For example. 
see this section (Extensive framing compensation (for DSL/ATM/PPPoe))
https://www.bufferbloat.net/projects/codel/wiki/Cake/