Looking for some education on ALTQ

[Daniel Hartmeier]

In your setup, the data is flowing from the iperf client (sender) on
NPX4 to the iperf server (receiver) on NPX1.

Apply the queue on the interface on NPX3 where the data is flowing
out, i.e. the interface facing NPX1. Queueing applies to outgoing
packets of an interface, not incoming packets.

It looks like you confused the interface, according to the drawing
the interface would be em0, but the ifconfig output places em0 in
the network towards NPX4. Then the pass rule in pf.conf uses em3.
It looks like you limited the (nearly non-existant) return traffic
instead.

When fixed, pfctl -vvsq should show quickly growing pkts and bytes
counters for test7788, of the order iperf reports (133KB vs. 597MB
in your output).

Kind regards,
Daniel