link effects between hub/switch and node only have downstream effect

```
1. Draw a link between a node and a switch and another node.
2. Configure 3ms delay on one link.
3. The round-trip delay will be 3ms, not 6ms as the GUI seems to indicate, as
one would expect.

The netem queues only effect outbound traffic. For a link to a switch there is
only one veth pair. For an upstream effect, a tc netem queue can be placed on
the veth installed in the namespace container. Drawback here is that this is
exposed to the "user" inside the container, and any queuing an app or daemon
may apply. Another option is to try using the Intermediate Functional Block
pseudo-device IFB, described here:

http://www.linuxfoundation.org/collaborate/workgroups/networking/netem#How_can_I
_use_netem_on_incoming_traffic.3F

Described in blog entry here:
http://coreemu.blogspot.com/2013/12/asymmetric-links-and-jitter.html

```

Original issue reported on code.google.com by `ahrenh...@gmail.com` on 3 Dec 2013 at 10:19