cannot attach child qdisc on netem

[Daniel Smilkov]

Binary package hint: iproute

In Ubuntu 9.10 when you write these 2 commands:

tc qdisc add dev eth0 root handle 1: netem delay 20ms
tc qdisc add dev eth0 parent 1: netem delay 20ms (doesn't matter which qdisc you attach)

it says: RTNETLINK answers: Invalid argument

In the previous ubuntu versions it works (also in all other Linux distributions).
SO, when you place a netem qdisc, you cannot attach a child qdisc, and you should.

[Arnd (arnd-arndnet)]

Netem became classless with kernel 2.6.29.
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=02201464119334690fe209849843881b8e9cfa9f

Because you cannot attach a child qdisc to a classless qdisc, this means that netem no longer supports child qdisc.

I'm afraid this is not a bug.

[Stéphane Graber (stgraber)]

One way or another, something changed in iproute and it's no longer failing (it might be ignoring part of it though).