Please Scroll down for more info. The vertical bars represent the range of time taken by packets of each size. Note the variation in round trip time. Ideally, the vertical bars should be very short, and lined up diagonally on the graph.
Tall bars indicate routing delays.
Note also that the bandwidth estimate will be limited by the round trip over the link. If the nameserver isn't responding quickly, websurfing can be tediously slow. Routers may set a low priority for ICMP Ping packets when they are nearing their load limit.