Midterm Exam #2 Review
• Exam time is July 5th during class time.
• The second homework and lecture content after
first mid-exam until this class will be covered.
• You need to compute out the final numerical
results in your answer. Do not simply write down
the formula as your answer.
– You can bring a calculator (no computer, iPhone, etc)
Question Types
– Knowledge questions
– True or false statement (explain why)
– Protocol
– Calculations
Knowledge Question Examples
• Compare pros and cons for go-back-N and
selective repeat ARQ?
– Go-back-N: pro: single timer, simple con: not efficient,
waste bandwidth when a packet is lost/broken
– Selective repeat: pro: efficient, only lost/broken
packets need retransmission con: complicated with
multiple timers, receiver needs a buffer to buffer outof-order packets
• Difference between “Ethernet hub” and “Ethernet
switch”?
• IPv6 uses how many bits for addresses?
Knowledge Question Examples
• Difference between Ethernet switch and router?
• What is VLAN? Its advantages?
• Interpret IP address block “a.b.c.d/n”? How
many IPs in it? First address? Last address?
• What is NAT? Its pros and cons?
• How many bytes are used for MAC address? IP
address? IPv6 address?
• What are the three blocks of private IP subnets?
• What is the minimum Hamming distance?
Protocol Example
• Stop-and-wait ARQ for noisy channel (hw2, Q9)
• CRC circuit design (homework 2)
• Bit stuffing and byte stuffing (ch11, homework 2)
Calculation Problem Examples
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Hamming Distance (ch10, Page 17-20)
Checksum (ch10, homework 2)
Go-back-N utilization compute (ch11.ppt, Page 34-37)
IP block subnet allocation (ch19.ppt, Page 34-40)
NAT table and address translation (ch19.ppt, Page 44)
• All questions in homework 2 will be covered
Midterm 2 Grade Statistics