Consider the DNS iterative query as shown in the picture below. Suppose the round-trip time (RTT) between the computer bit.vt.edu (and any other computer in vt.edu) and its local name server, jeru.cns.vt.edu, is 10 milliseconds, and that the RTT from dns.vt.edu to any other Internet site is 100 milliseconds.

The local DNS server cache at dns.vt.edu, and that the caches of all other DNS servers are initially empty.

1. How long is the time between when bit.vt.edu first makes sends a DNS query for the IP address of seas.ucla.edu, and the time that it gets a reply to that DNS query? Explain how you arrived at your answer.
2. Now suppose a second computer in vt.edu send a DNS query to its local name server, jeru.cns.poly.edu, and again asks for the IP address of seas.ucla.edu . How long is it until this query is satisfied?
    

Transcribed Image Text:

N root DNS server tl local DNS server jeru.cns.vt.edu 1|| 8 requesting host bit.vt.edu 3 4 5 7 TLD DNS server 6 authoritative DNS server ns1.dns.ucla.edu seas.ucla.edu N root DNS server tl local DNS server jeru.cns.vt.edu 1|| 8 requesting host bit.vt.edu 3 4 5 7 TLD DNS server 6 authoritative DNS server ns1.dns.ucla.edu seas.ucla.edu

Answer rating: 100% (QA)

To determine the total time between when bitvtedu first sends a DNS query for the IP address of seas... View the full answer