tpod173
Newbie level 2
hi to all ...
can i get for this Q's --solutions please ..if any one knows post it imm or PM me the solutions .thnx in advance ..
-----------------
1. (20 pts) IP fragmentation and reassembly
A message is sent from host A to host B. The message size is 2300 bytes and A's protocol
breaks the message into three datagrams. The frst two are 800 bytes of data and the third
is 700 bytes of data. The header size is not specied but the size is in addition the data byte allotment. There exist several routes from A to B.
_ Datagram 1 goes through routers C then D. C's MTU is 400 and D's MTU is 300.
_ Datagram 2 goes through routers C then E. C's MTU is 400 and E's MTU is 500.
_ Datagram 3 goes through router F. F's MTU is 300.
Assume the following _elds are available for fragmentation and reassembly in the header of each datagram.
_ ID
_ Data length in bytes
_ Fragment O_set in bytes
_ More Flag
Notice that these fields are taken from IP with modifications made for simplification. The
major simplification is all fields are in byte units. You may assume no errors or congestion occur during transmission and propagation.
(a) (2 pts) Draw a possible internetwork of hosts and routers from the description given.
(b) (3 pts) Show the header (only four _elds) for each of the three datagram leaving A.
(c) (6 pts) Show the header for each entering and exiting datagram at each router.
(d) (9 pts) Show, using a diagram of data structures and header information, how B re-
assembles the incoming datagrams to the original three datagrams. Demonstrate how
your data structure and header are used together. No code is necessary. You may not
assume any particular order of datagram delivery.
2. (10 pts) UDP and TCP
(a) ( 5 pts) Why is UDP needed? Why can't a user program directly access IP?
(b) (5 pts) Compare and contrast UDP sockets and TCP sockets. Answer this question from both the transport and application level (programmer) perspective.
3. (10 pts) IPv4 and IPv6
List two new or changed features in IPv6. Discuss how each one a_ects the Internet Protocol including the a_ects to inter-networking issues. Be thorough in your discussion.
4. (10 pts) ATM
(a) (2 pts) What features of ATM provide for a high-speed network? Provide a brief de-
scription of how each feature a_ects the speed of the network.
(b) (2 pts) What does ATM guarantee about the delivery of cells and what does it not
guarantee (regardless of quality of service)?
5. (10 pts) High-speed LANs
(a) (4 pts) What hardware and software changes/additions have been made to traditional
Ethernet to achieve 100 Mbps, 1000 Mbps and 10000 Mbps(10 Gbps)?
(b) (6 pts) Compare and contrast hubs, layer 2 switches, and layer 3 switches relative to
achieving high data rates.
6. (10 pts) High-speed LANs II
Consider a bus LAN with a number of equally spaced stations with a data rate of 1000 Mbps and a bus length of 1.8 km.
(a) (5 pts) What is the mean time to send a frame of 4000 bits to another station, measured from the beginning of transmission to the end of reception? Assume a propagation speed of 300m/_s.
(b) ( 5 pts) If two stations begin to transmit at exactly the same time, their packets will
interfere with each other. If each transmitting station monitors the bus during trans-
mission, how long before it notices an interference, in seconds? In bit times?
7. (15 pts)Probability
(a) (5 pts) A taxicab was involved in a fatal hit-and-run accident at night. Two cab com-
panies, The Green and The Blue, operate in the city. You are told that:
• 85% of the cabs in the city are Green and 15% are Blue
• A witness identified the cab as Blue
The court tested the reliability of the witness under the same circumstances that existed
on the night of the accident and concluded that the witness was correct in identifying
the color of the cab 80% of the time. What is the probability that the cab involved in
the incident was Blue rather than Green?
(b) (5 pts) In the carnival game known as chuck-a-luck, a player plays an amount E as an
entrance fee, selects a number between one and six, and then rolls three dice. If all three
dice show the number selected, the player is paid four times the entrance fee; if two dice
shows the number, the player is paid three times the entrance fee, and if only one die
shows the number, the player is paid twice the entrance fee. If the selected number does
not show up, the player is paid nothing. Let X denote the player's gain in a single play
of this game, and assume the dice are fair. Determine the probability function of X.
8. (15 pts)Queuing Analysis
(a) (5 pts) Consider a coffee counter with a single server at which tired students arrive
according to a Poisson process. Let the mean arrival rate be two students per ten
minutes and assume the serving time is exponentially distributed with an average of 180
seconds per student.
i. What is the average queue length?
ii. How long does a student have to wait in the queue?
iii. Find the average queue length and waiting time in the queue if the service time
decreases to 120 seconds per student.
(b) (5pts) The owner of a shop observes that on average 18 customers per hour arrive and
there are typically 8 customers in the shop. What is the average length of time each
customer spends in the shop?
can i get for this Q's --solutions please ..if any one knows post it imm or PM me the solutions .thnx in advance ..
-----------------
1. (20 pts) IP fragmentation and reassembly
A message is sent from host A to host B. The message size is 2300 bytes and A's protocol
breaks the message into three datagrams. The frst two are 800 bytes of data and the third
is 700 bytes of data. The header size is not specied but the size is in addition the data byte allotment. There exist several routes from A to B.
_ Datagram 1 goes through routers C then D. C's MTU is 400 and D's MTU is 300.
_ Datagram 2 goes through routers C then E. C's MTU is 400 and E's MTU is 500.
_ Datagram 3 goes through router F. F's MTU is 300.
Assume the following _elds are available for fragmentation and reassembly in the header of each datagram.
_ ID
_ Data length in bytes
_ Fragment O_set in bytes
_ More Flag
Notice that these fields are taken from IP with modifications made for simplification. The
major simplification is all fields are in byte units. You may assume no errors or congestion occur during transmission and propagation.
(a) (2 pts) Draw a possible internetwork of hosts and routers from the description given.
(b) (3 pts) Show the header (only four _elds) for each of the three datagram leaving A.
(c) (6 pts) Show the header for each entering and exiting datagram at each router.
(d) (9 pts) Show, using a diagram of data structures and header information, how B re-
assembles the incoming datagrams to the original three datagrams. Demonstrate how
your data structure and header are used together. No code is necessary. You may not
assume any particular order of datagram delivery.
2. (10 pts) UDP and TCP
(a) ( 5 pts) Why is UDP needed? Why can't a user program directly access IP?
(b) (5 pts) Compare and contrast UDP sockets and TCP sockets. Answer this question from both the transport and application level (programmer) perspective.
3. (10 pts) IPv4 and IPv6
List two new or changed features in IPv6. Discuss how each one a_ects the Internet Protocol including the a_ects to inter-networking issues. Be thorough in your discussion.
4. (10 pts) ATM
(a) (2 pts) What features of ATM provide for a high-speed network? Provide a brief de-
scription of how each feature a_ects the speed of the network.
(b) (2 pts) What does ATM guarantee about the delivery of cells and what does it not
guarantee (regardless of quality of service)?
5. (10 pts) High-speed LANs
(a) (4 pts) What hardware and software changes/additions have been made to traditional
Ethernet to achieve 100 Mbps, 1000 Mbps and 10000 Mbps(10 Gbps)?
(b) (6 pts) Compare and contrast hubs, layer 2 switches, and layer 3 switches relative to
achieving high data rates.
6. (10 pts) High-speed LANs II
Consider a bus LAN with a number of equally spaced stations with a data rate of 1000 Mbps and a bus length of 1.8 km.
(a) (5 pts) What is the mean time to send a frame of 4000 bits to another station, measured from the beginning of transmission to the end of reception? Assume a propagation speed of 300m/_s.
(b) ( 5 pts) If two stations begin to transmit at exactly the same time, their packets will
interfere with each other. If each transmitting station monitors the bus during trans-
mission, how long before it notices an interference, in seconds? In bit times?
7. (15 pts)Probability
(a) (5 pts) A taxicab was involved in a fatal hit-and-run accident at night. Two cab com-
panies, The Green and The Blue, operate in the city. You are told that:
• 85% of the cabs in the city are Green and 15% are Blue
• A witness identified the cab as Blue
The court tested the reliability of the witness under the same circumstances that existed
on the night of the accident and concluded that the witness was correct in identifying
the color of the cab 80% of the time. What is the probability that the cab involved in
the incident was Blue rather than Green?
(b) (5 pts) In the carnival game known as chuck-a-luck, a player plays an amount E as an
entrance fee, selects a number between one and six, and then rolls three dice. If all three
dice show the number selected, the player is paid four times the entrance fee; if two dice
shows the number, the player is paid three times the entrance fee, and if only one die
shows the number, the player is paid twice the entrance fee. If the selected number does
not show up, the player is paid nothing. Let X denote the player's gain in a single play
of this game, and assume the dice are fair. Determine the probability function of X.
8. (15 pts)Queuing Analysis
(a) (5 pts) Consider a coffee counter with a single server at which tired students arrive
according to a Poisson process. Let the mean arrival rate be two students per ten
minutes and assume the serving time is exponentially distributed with an average of 180
seconds per student.
i. What is the average queue length?
ii. How long does a student have to wait in the queue?
iii. Find the average queue length and waiting time in the queue if the service time
decreases to 120 seconds per student.
(b) (5pts) The owner of a shop observes that on average 18 customers per hour arrive and
there are typically 8 customers in the shop. What is the average length of time each
customer spends in the shop?
