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ECE3076 Quiz 1 p. 1 of 3
ECE3076, Internetwork Programming, QUIZ 1
Spring 2007
Prof. John A. Cop eland Feb. 21, 2007
E-Mail: copeland@ece.gatech.edu
RULES.
i This quiz is not open book. One original sheet of hand-written notes may be used . Calculators are ok.
ii Answer all questions and show all work to receive fu ll credit. Use back of sheets only if necessary.
iii All sub-questions have the same weight (3.3%).
iv Please do not ask the proctors any questions during the exam about exam questions. Part of the test is
understanding the question, as written, without supplemental information. If you feel additional d ata is needed to solve the
problem, make (and state) an assump tion and then work the problem.
v. This is a time-limited test. All papers must be turned in 70 minutes after the start. If you find you are
taking more than 10 minutes on a par ticular problem, move on and come back to that problem after finishing the oth ers. The
Georgia Tech Honor Code applies (see last page).
Question 1 โ The Internet
a. __Autonomous__ IANA assigns blocks of IP addresses to what kind of Systems (hint: abbreviation is AS)?
b. _ Authoritativ e___ What type(s) of DNS Server has the IP addres ses of all names in the AS?
c. _ Top Level (T LD) What type of DNS Server h as the IP addresses of every syst em DNS with a ".edu" ending.
d. ____ Root ______ What type of DNS Server h as the IP address for the DNS servers for .edu, .com, .gov, .mil, ... .
e. _ Connectionless_ Even though TCP can set up connections between hosts, the Internet itself (IP) is "______"?
f. __TTL, Time to Live__ The "traceroute" program takes advantage of the fact that each router de crements which field in
the IP header?
Question 2 โ Bandwidth-Delay Product
a. _____37.5_____ (kbytes) If the round-trip tim e (RTT) for a dedicated 10 Mbit/s connection to California is 30 ms, what
is minimum TCP widow size that w ill allow this channel to be fully utilized? Rate x Delay = 10 Mbits/s x 0.030 s / 8 b/Byte
b. _________10_______ (Mbits/s) What will the maximu m throughput be if the window is 64 kbytes in the example above.
Any Window size larger than Rat e x Delay will al low be limited by Rate, which is < Window / De lay
c. _______1001 0001__________ What is the one's compliment 8-bit checksum of the following 8-bit binary numbers :
1 0 0 0 1 1 0 1
1 1 1 0 0 0 0 0
1 0 1 1 0 1 1 0 1 -> 0 1 1 0 1 1 1 0 then bit-wise compliment
On a shared network, what two factors cause TCP sending hosts to slow down and relieve congestion:
d. __Buffer fill (Queuing) delays__ What change in the network (routers) causes RTT to increase?
e. ______Lost packets_______ What causes the TCP sender's window to decrease?
