Font size
WorksheetsIT420 HW 3
Total questions: 17
Worksheet time: 4hrs 15mins
Assume odd parity. The single-bit parity for the data 01101011 is
0
1
00010100
Cannot be determined
A receiver receives a message containing redundant bits for error checking and uses those bits to determine that no error has occurred. What does the receiver then do with the redundant bits?
discards them
passes them to the next layer up in the network model at the receiver
saves them for future use
returns them to the sender
Can single-bit parity detect an error that flips exactly two data bits?
No
Yes
Sometimes - it depends on the data
The checksum for 1000 bytes of data is 16 bits long. Assuming the same checksum algorithm is used, how long will the checksum be for 500 bytes of data?
500 bits
16 bits
8 bits
cannot be determined
A CRC is 5 bits long. How long is the divisor?
5 bits
6 bits
7 bits
cannot be determined
Assume 4-bit wide units of data. Calculate the checksum for 1101 1001
0111
0101
1 0 0 0
1010
Assume a bit sequence of 10110 and a divisor of 1001.
Generate the CRC
100
001
101
Assume a bit sequence of 10110 and a divisor of 1001.
Check the CRC
checks, since remainder is 0
does not check, since remainder is not 0
A CRC polynomial is x2 + 1. What is the divisor?
(a)
A CRC divisor is 1011001. What is the polynomial?
(a)
In what kind of multiplexing does each sender use some of the bandwidth of the link for all time?
FDM
TDM
both of these
neither of these
What scheme multiplexes digital signals?
FDM
TDM
both of these
neither of these
What is the minimum bandwidth of the output of a FDM multiplexer that combines 5 channels of 3KHz each? Assume 500Hz guard bands.
(a)
Three FDM multiplexers are connected as shown above. If each input has a bandwidth of 24 MHz, what is the minimum bandwidth of the output from each multiplexer? Assume a 3 MHz guard band between channels.
For the top first-layer multiplexers: 72 MHz
For the bottom first layer multiplexer: 105 MHz
For the second-layer multiplexer: 186 MHz
For the top first-layer multiplexers: 78 MHz
For the bottom first layer multiplexer: 96 MHz
For the protocols listed below, select the controlled access protocol(s).
Polling
FDMA
Token Passing
TDMA
Reservation
For the protocols listed below, select the random access protocol(s).
CDMA
TDMA
CSMA/CD
CSMA/CA
For the protocols listed below, select the channelization access protocol(s).
FDMA
Polling
CDMA
TDMA
