Hello Abhishek,
>> When we trace route one ip address why it show 3 packets with 3 different types of ms value on every hop. Please explain .It is interview question .
Because traceroute discovery actually makes three attempts for each TTL value to find out intermediate router hops.
This allows to see if there are some alternative next-hops in the path.
Even if a single path / single next-hop exists it reports the results of each attempt so you see three measures of delay expressed in ms for each hop.
The delay measure is possible for the presence of timestamps in the probe packets.
After having done the three attempts the router will increment the TTL by 1 before sending other three probes and so on until the final destination is reached or the maximum number of hops is reached (default to 30).
Actually also the UDP destination port is incremented.
See the link below:
https://www.cisco.com/c/en/us/support/docs/ios-nx-os-software/ios-software-releases-121-mainline/12778-ping-traceroute.html#traceroute
Hope to help
Giuseppe
