Download Assignment BTech 6_1

B.Tech. (CS/IT) 6th Semester Assignment – 1
Computer Network –II (TCS-605/TIT605)
Date of Submission: 09-03-2016
1. Discuss how a hierarchical organization of the Internet has made it possible to scale to millions of users.
2. Compare and contrast the advertisements used by RIP and OSPF.
3. Find the shortest path (Dijkstra Algorithm) for all the nodes from node A.
7
4
A
E
2
C
2
5
4
1
G
1
2
3
B
D
F
6
4. For the network given below, give the distance-vector routing table at node B when
(i). Each node knows only the distances to its immediate neighbors.
(ii). Each node has reported the information it had in the preceding step to its immediate
neighbors.
(iii). Step (ii) happens a second time.
7
A
3
4
2
B
5
C
E
2
9
5
D
What is the difference between a group-shared tree and a source-based tree in the context of multicast
routing?
6. For each of the three general approaches we studied for broadcast communication (uncontrolled
flooding, controlled flooding, and spanning-tree broadcast), are the following statements true or false?
You may assume that no packets are lost due to buffer overflow and all packets are delivered on a
link in the order in which they were sent.
a. A node may receive multiple copies of the same packet.
b. A node may forward multiple copies of a packet over the same outgoing link.
7. Suppose nodes A, B, and C each attach to the same broadcast LAN (through their adapters). If A
sends thousands of IP datagrams to B with each encapsulating frame addressed to the MAC address
of B, will C’s adapter process these frames? If so, will C’s adapter pass the IP datagrams in these
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
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frames to the network layer C? How would your answers change if A sends frames with the MAC
broadcast address?
Why is an ARP query sent within a broadcast frame? Why is an ARP response sent within a frame
with a specific destination MAC address?
Suppose that N switches supporting K VLAN groups are to be connected via a trunking protocol.
How many ports are needed to connect the switches? Justify your answer.
Suppose the information content of a packet is the bit pattern 1110 0110 1001 1101 and an even
parity scheme is being used. What would the value of the field containing the parity bits be for the
case of a two-dimensional parity scheme? Your answer should be such that a minimum-length
checksum field is used.
Consider the 7-bit generator, G=10011, and suppose that D has the value 1010101010. What is the
value of R?
Suppose nodes A and B are on the same 10 Mbps broadcast channel, and the propagation delay
between the two nodes is 325 bit times. Suppose CSMA/CD and Ethernet packets are used for this
broadcast channel. Suppose node A begins transmitting a frame and, before it finishes, node B begins
transmitting a frame. Can A finish transmitting before it detects that B has transmitted? Why or why
not? If the answer is yes, then A incorrectly believes that its frame was successfully transmitted
without a collision. Hint: Suppose at time t = 0 bits, A begins transmitting a frame. In the worst case,
A transmits a minimum-sized frame of 512 + 64 bit times. So A would finish transmitting the frame
at t = 512 + 64 bit times. Thus, the answer is no, if B’s signal reaches Abefore bit time t = 512 + 64
bits. In the worst case, when does B’s signal reach A?
Recall that with the CSMA/CD protocol, the adapter waits K _ 512 bit times after a collision, where K
is drawn randomly. For K = 100, how long does the adapter wait until returning to Step 2 for a 10
Mbps broadcast channel? For a 100 Mbps broadcast channel?
In an infinite-population slotted ALOHA system, the mean number of slots a station waits between a
collision and its retransmission is 4. Plot the delay versus throughput curve for this system.
How long does a station, s, have to wait in the worst case before it can start transmitting its frame
over a LAN that uses the basic bit-map protocol?
A LAN uses Mok and Ward's version of binary countdown. At a certain instant, the ten stations have
the virtual station numbers 8, 2, 4, 5, 1, 7, 3, 6, 9, and 0. The next three stations to send are 4, 3, and
9, in that order. What are the new virtual station numbers after all three have finished their
transmissions?
Sixteen stations, numbered 1 through 16, are contending for the use of a shared channel by using the
adaptive tree walk protocol. If all the stations whose addresses are prime numbers suddenly become
ready at once, how many bit slots are needed to resolve the contention?
A collection of 2n stations uses the adaptive tree walk protocol to arbitrate access to a shared cable. At
a certain instant, two of them become ready. What are the minimum, maximum, and mean number of
slots to walk the tree if 2n -1?
The wireless LANs that we studied used protocols such as MACA instead of using CSMA/CD. Under
what conditions, if any, would it be possible to use CSMA/CD instead?