A common problem is to ask for more links then there are physical
interfaces (ethernet cards) for on your node(s). If that happens, you will
see a message like:
*** No possible mapping for node0053 Too many links of type ethernet!
The typical testbed machine has 1-4 available network cards, which is limit
of links that can be incident on those nodes. One way to get around this
limitation is to use a single large lan instead of point to point links.
Another approach is to use multiplexed links, which allows you to
multiplex several virtual network links onto a single physical ethernet
link using VLAN tagged devices. You are of course still limited to the
bandwidth of the underlying physical device, but if your experiment does not
saturate all your links, this works very well.
To turn on link multiplexing, add this to your links:
You will also need to do one of the following on each of your links:
link1.best_effort = True link1.best_effort = True
Or if you want too allocate specific bandwidths to each link (and make sure
that those bandwidths are enforced:
link1.bandwidth = 10000 link2.bandwidth = 10000
Note that the bandwidth is specified in Kbps. Also, note that all of the
bandwidths have to sum to less then the bandwidth on the physical interface.
For example, if a node has a single 10G physical interface, you can
multiplex ten 1G links on top of it.