[Mini-NDN] NdnRoutingHelper error in large topologies

[Philipp Moll]

Hi guys,

I am currently working on a MiniNDN scenario evaluation, where I need a 
large network topology. I pushed the Geant topology to gerrit yesterday. 
This topology has 45 nodes and quite high connectivity between the 
nodes. Installing all possible routes with the NdnRoutingHelper takes 
about 20 minutes. For me, this is too long when considering that my 
actual evaluation only takes 10 minutes.

When restricting the routes to install to the shortest path only to save 
time (NdnRoutingHelper.calculateNPossibleRoutes(nFaces=1)), the 
computeDijkastra method fails in line 241 when using the Geant topology.

I am not familiar with the ndn_routing_helper code, that's why I'll use 
a workaround. But maybe someone who is familiar with the routing-helper 
can find the problem's cause.

Thanks,
Philipp