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WorksheetsCN_Minor2
Total questions: 20
Worksheet time: 17mins
Name
Class
Date
1.
In link state routing, if the time interval between periodic updates is T, which of the following should hold true with respect to the ageing timer A associated with a link state packet entry at a router?
a)
A < T
b)
A > T
c)
A = T
d)
A ≠ T
2.
Suppose N packets arrive simultaneously at a router every T seconds. Suppose the packets are of size S bits and the transmission rate of the router is R bps. What should the minimum value of T be such that the queuing delay does not grow without bound?
a)
(N-1)S/R
b)
NS/R
c)
(N-2)S/R
d)
NR/S
3.
What is the IP source address of a DHCP discover message generated by a host?
a)
0.0.0.0
b)
255.255.255.255
c)
Host’s MAC address
d)
The last 4 bytes of the host’s MAC address
4.
Host A wants to send a packet to Host B and Host B needs to reply back with a packet to Host A. In response to this, how many messages are actually exchanged on the link including the packets that A and B need to send? Assume empty ARP cache at both nodes and that Host A knows the IP address of Host B
a)
5
b)
6
c)
4
d)
3
5.
Host A is connected to another host B directly. Assume that the propagation delay is less than the transmission delay on this link. If host A starts transmission at t=0, at time equal to transmission delay, where is the first bit of the packet?
a)
At host A
b)
At host B
c)
On the link
d)
Removed from the link
6.
What is the maximum number of bytes that can be accommodated as UDP payload?
a)
65507
b)
65535
c)
65135
d)
65555
7.
A user wishes to download a webpage which has 3 embed images within it. Assume that all objects reside on the same server. How many HTTP response messages are sent?
a)
5
b)
3
c)
4
d)
6
8.
Two hosts A and B are communicating with each other using TCP. Assume the sequence number field starts at 0 and the receiver employs cummulative ack. A has successfully sent 465 bytes of data which were also acked by B. Suppose A were now to send 3 segments of size 100, 40 and 60 each. We will call these three segments, first, second and third. Suppose the second segment was received before the first and third segment, what will the ack value be in the ack generated as a consequence of receiving this second segment?
a)
565
b)
465
c)
505
d)
605
9.
What should be the maximum size of a file such that the TCP sequence number doesn’t wrap around before the file transfer finishes? Assume a segment size of 536 bytes. Express the file size in Gigabytes.
a)
4.3
b)
4
c)
2.8
d)
4.8
10.
Which of the following is TRUE about Routing Information Protocol (RIP) and Open Shortest Path First (OSPF)
a)
RIP uses distance vector routing and OSPF uses link state routing
b)
OSPF uses distance vector routing and RIP uses link state routing
c)
Both RIP and OSPF use link state routing
d)
Both RIP and OSPF use distance vector routing
11.
You need to subnet a network that has 5 subnets, each with at least 16 hosts. Which classful subnet mask would you use?
a)
255.255.255.192
b)
255.255.255.255
c)
255.255.255.224
d)
255.255.255.240
12.
Which of the following is loopback address ?
a)
127.0.01
b)
127.0.0.0
c)
127.0.1.0
d)
127.1.1.1
13.
Vacation daemons work by sending an automated out of office emails. Who implements these daemons, user agent or message transfer agent? Note that one does use user-agent to set them up but who actually sends (not forwards) the reply emails?
a)
Message-transfer-agent
b)
User-agent<br /><br />
c)
Either User-agent or Message-transfer-agent
d)
Neither User-agent nor Message-transfer-agent
14.
Which of the following are disadvantages of using NAT?<br /><br />1. Translation introduces switching path delays.<br />2. Conserves legally registered addresses.<br />3. Causes loss of end-to-end IP traceability.<br />4. Increases flexibility when connecting to the Internet.<br />5. Certain applications will not function with NAT enabled.<br />6. Reduces address overlap occurrence.
a)
1, 3. 5
b)
2, 4, 6
c)
1, 2, 6
d)
3, 5, 6
15.
If a code has a hamming distance of 7, how many errors can it detect?
a)
1
b)
6
c)
21
d)
14
16.
Assume the standard deviation around the average is 5ms. Which among the following would be a suitable timeout value for the ARQ algorithm?
a)
20ms
b)
10ms
c)
12ms
d)
15ms
17.
Which of the following is private IP address?
a)
255.255.255.255
b)
1.0.0.1
c)
128.0.0.1
d)
192.168.24.43
18.
Which of the following statements are TRUE?<br />(S1) TCP handles both congestion and flow control<br />(S2) UDP handles congestion but not flow control<br />(S3) Fast retransmit deals with congestion but not flow control<br />(S4) Slow start mechanism deals with both congestion and flow control
a)
S1 and S2
b)
S1, S4, and S2
c)
S1 and S3
d)
S3 and S4
19.
What is the IP source address of a DHCP discover message generated by a host?
a)
Host’s MAC address
b)
255.255.255.255
c)
0.0.0.0
d)
The last 4 bytes of the host’s MAC address
20.
Which of the following corresponds to class C addressing ?
a)
110, NID(24), HID(8)
b)
100, NID(24), HID(8)
c)
000, NID(8), HID(24)
d)
110, NID(8), HID(24)
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