When issue the traceroute command, I get the feeback
me@alpha:~$ traceroute www.youtube.com
traceroute to www.youtube.com (203.98.7.65), 64 hops max
.........
4 61.148.6.201 2.463ms 2.298ms 2.119ms
5 202.96.12.121 2.714ms 2.520ms 2.444ms
6 219.158.5.154 7.203ms 8.785ms 6.966ms
7 219.158.16.66 5.199ms 9.587ms 6.808ms
8 219.158.103.6 342.937ms 307.527ms 308.729ms
9 195.2.22.53 317.321ms 243.056ms 359.128ms
10 195.2.8.137 271.794ms 342.338ms 306.371ms
11 * * *
12 * * *
13 * * *
14 * * *
15 * * *
16 * * *
What does the stars mean?