The MPLS/RSVP-TE/LDP protocol models have been revised and mostly rebuilt
from scratch by Vojta Janota since the INET-20050922 release. This network
already features the new simulation models.

This is a sample to demonstrate reroute and preemption handling.

Following description refers to the nam trace file genereated by the simulation
run.

Two LSPs are established on simulation startup. The green one is a higher
priority path, the orange one has a regular priority. Later, the green path is
rerouted to the same hop-route the orange one uses and since there is not enough
bandwidth to serve both, the lower priority orange path is preempted.

Remarks:

Rerouting in RSVP-TE works in 3 steps:

   1. New LSP (A) is created in the same session as the path being rerouted (B).

   2. After (A) is successfully built, the ingress starts forwarding the traffic
      via this new path.

   3. Old LSP (B) is torn down (usually after some short period).

In this simulation, this process is controlled by the ScenarioManager. The
small delay between the preemption and the actual act of rerouting the traffic
onto new path is caused by the static timing of the process in the
scenario.xml, i.e. traffic is not rerouted as soon as the (A) is ready, but
after a fixed period after (A) starts to be built.

After the orange path is preempted, there is no LSP for the traffic coming from
host2 and this traffic is thus handled as a regular best-effort IP traffic.
Particularly this means:

   1. its color changes to black (black is used for L3-routed IP datagrams)

   2. it's routed via the routing table
