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hw3key - 2 RTT : HTML le d 3 3 e (2 RTT ) : 3 objects, 3 at...

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EEE459 Homework 3 answer key 5 points/review question: 19 10 points/problem: 4, 6, 7, and 20 Review Question 19. Yes. The mail and web servers can have the same alias for a host name. The record type for the mail server would be MX. Problems 4. At the application layer, HTTP and DNS are used. At the transport layer, these protocols use TCP and UDP respectively. 6. There is one request and reply for each of the n DNS servers, one RTT 0 to set up the TCP connection, and another RTT 0 to get the object (HTML page): 2 RTT 0 + Σ n 1 RTT i 7. In each case, there is still the same Σ n 1 RTT i delay, plus the time it takes to get the web page: a) Non-persistent: 2 RTT 0 : HTML file 3 · (2 RTT 0 ) : 3 objects, 1 at a time 8 RTT 0 b) Non-persistent with (3) parallel connections:
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Unformatted text preview: 2 RTT : HTML le d 3 3 e (2 RTT ) : 3 objects, 3 at a time 4 RTT c) Persistent w/ pipelining: 2 RTT : HTML le RTT : all 3 requests sent together 3 RTT d) Persistent w/o pipelining: 2 RTT : HTML le 3 RTT : 3 objects, requested 1 at a time 5 RTT 20. Initially, the query is sent to all N neighbors. On every successive step, only N-1 queries are forwarded, because we exclude the host that sent the last query. This proceeds for K-1 steps (when the count is exhausted). Therefore, the number of messages at each step is N ( N-1) i , and the total number is K-1 i =0 N ( N-1) i = N (( N-1) K-1) N-2 1...
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