From Figure 1 we see that there may be many alternate
paths between a source and destination. DSR chooses the route
with the “best” metric and caches the remaining routes as
backups for future use. A malicious black hole node would
respond to RREQ packets, falsely claiming that it has the best
routes to the destination. It does this to trick the sending node
into routing information through it; this information then gets
dropped and never reaches the destination.