WorksheetsCN Minor1
Total questions: 20
Worksheet time: 19mins
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?
At host A
At host B
On the link
Removed from the Link
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?
NS/R
(N-1)S/R
(N-2)S/R
NR/S
Which of the following metric is often ignored by the users while evaluating a network
Dealy
Throughput
Security
Losses
Which of the following is an advantage of layering?
Helps troubleshooting
Reduces complexity Helps
interoperability
All
Latency of a channel does not directly depend on
Media characteristics
Error recovery
Signal propogation speed
Transmission distance
Which of the following parameter cannot be considered to classify networks
Cost
Size
Functionality
Physical Connectivity
Switches and bridges lies on _________ layer
Transport
Physical
Network
Data link
Primary job of a MAC layer is
data compression
Acknowledging the data transmissions
Allowing multiple nodes to share a single medium
Ensuring error free transmissions
MAC address is given to a device when ____
It is manufactured
Drivers are installed
Network admin decides
the device bootsup
The purpose of twisting the wires in unshielded twisted-pair cable is to reduce
Noise
Attenuation
Electro magnetic interference
Cross talk
Network Interface Cards primary functionality includes
connects the clients, servers and peripherals to the network through a port
connects networks with different protocols like TCP/IP
boost the signal between two cable segments or wireless access points
allows you to segment a large network into smaller, efficient networks
Is the alternating bit protocol the same as Go-Back-N protocol with a sender and receiver window size of 1?
Yes
No
May be
Never be
In which of the following MAC protocols is there a delay (latency) associated with accessing the channel to transmit a packet? Assume the packet is at the head of the queue.
CDMA
FDMA
Polling
SDMA
In which of the following techniques can a node prepared to receive from its sender receive (whether it wants to or not) other sender’s transmissions? Assume a simple receiver with no special capabilities.
Random Access
FDMA
CDMA
SDMA
Which of the following encodings have problem with long sequence of 1’s
Manchester
NRZI
NRZ
4B/5B
A switch can connect 10Mbps and a 100Mbps link, while a hub cannot. Why?
Lack of buffer
Hub is not reliable
Hub is expensive
Hub does not have a forward option
In a sliding window protocol, suppose 8 bits were assigned to the sequence number field. How many packets would have to be sent for the sequence numbers to wrap around? That is, say you sent a packet with sequence no 5, how many more packets need to be sent after this for you to see the same sequence number 5 again?
128
255
256
127
CRC bits: Suppose a 16 bit message is converted into a 20 bit codeword by CRC, answer the following. A) What is the degree of the message polynomial M(x)? B) What is the degree of the divisor polynomial C(x)?
15 and 4
16 and 4
15 and 5
16 and 5
Stop and wait protocol over an asymmetric link: Suppose the stop and wait protocol is employed over an asymmetric link A to B. The A to B link bandwidth is 1Mbps with a propagation delay of 20ms, however the B to A link bandwidth is 10Mbps with a propagation delay of 10ms (reverse link different from forward link, that is asymmetric). Assume a data packet size of 1000 byte and an ACK size of 100 byte. What is the throughput achieved by the protocol? Ignore other delays. Express answer in kbps.
205
220
210
218
Which of the following tasks is not done by data link layer?
channel coding
flow control
framing
error control
