Community-Lab introduction

Modified script.txt from [6c76a054b8] to [c3079155a8].

   109    109   - Each node is able to run several experiments simultaneously.
   110    110   - An experiment runs in a given node as a sliver which holds a share of its
   111    111     resources (CPU, memory, disk, bandwidth, interfaces…).
   112    112   - Finally, related slivers are grouped in a slice for management purposes.
   113    113   - All these concepts are inspired in PlanetLab. *##*
   114    114   
   115    115   ** Node architecture
   116         -allows the realization of these concepts.  *##* A node consists of a CD, a RD
   117         -and a rD connected to the same wired local network.
          116  +allows the realization of these concepts.  *##* A node is a RD connected to a CN
          117  +through the wired local network of a CD.
   118    118   
   119    119   - The community device
   120    120     - Completely normal CN device, so existing ones can be used.
   121    121     - routes traffic between the CN and the local network (which runs no routing
   122    122       protocol).
   123    123   - The research device
   124    124     - Usually more powerful than CD, since experiments run here.