Ugh, tell me about it.. worse still if the nodes aren't all on fast connections. One thing we had to deal with is where a mobile operator had two sites with multiple nodes per site. Our nodes were connected through a high speed network on each site, but the connection between the two sites was very slow and unreliable, so we had to change our software so that it would "prefer" to communicate with other nodes on the same site before trying the second site.