Q. The plain text message BAHI encrypted with RSA algorithm using e=3, d=7 and n=33 and the characters of the message are encoded using the values 00 to 25 for letters A to Z. Suppose character by character encryption was implemented. Then, the Cipher Text message is ............

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Q. If link transmits 4000 frames per second and each slot has 8 bits, the transmission rate of circuit of this TDM is ...............

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Q. Given the following statements:

(a) Frequency Division Multiplexing is a technique that can be applied when the bandwidth of a link is greater than combined bandwidth of signals to be transmitted.
(b) Wavelength Division Multiplexing (WDM) is an analog multiplexing Technique to combine optical signals.
(c) WDM is a Digital Multiplexing Technique.
(d) TDM is a Digital Multiplexing Technique.

Which of the following is correct?

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Q. A pure ALOHA Network transmit 200 bit frames using a shared channel with 200 Kbps bandwidth. If the system (all stations put together) produces 500 frames per second, then the throughput of the system is ..............

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Q. Match the following:

(a) Line coding                         (i) A technique to change analog signal to digital data.
(b) Block coding                       (ii) Provides synchronization without increasing
number of bits
(c) Scrambling                          (iii) Process of converting digital data to digital signal.
(d) Pulse code modulation    (iv) Provides redundancy to ensure synchronization
and inherits error detection.

Codes:
      (a)   (b)   (c)   (d)

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Q. Assume that we need to download text documents at the rate of 100 pages per minute. A page is an average of 24 lines with 80 characters in each line and each character requires 8 bits. Then the required bit rate of the channel is ................

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Q. Suppose that the time to do a null remote procedure call (RPC) (i.e, 0 data bytes) is 1.0 msec, with an additional 1.5 msec for every 1K of data. How long does it take to read 32 K from the file server as 32 1K RPCs?

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Q. Which of the following services is not provided by wireless access point in 802.11 WLAN?

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Q. Which of the following fields in IPv4 datagram is not related to fragmentation?

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Q. Four channels are multiplexed using TDM. If each channel sends 100 bytes/second and we multiplex 1 byte per channel, then the bit rate for the link is ...............

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Q. In a typical mobile phone system with hexagonal cells, it is forbidden to reuse a frequency band in adjacent cells. If 840 frequencies are available, how many can be used in a given cell?

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Q. Using p=3, q=13, d=7 and e=3 in the RSA algorithm, what is the value of ciphertext for a plain text 5?

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Q. Which of the following is not a congestion policy at network layer?

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Q. The combination of an IP address and a port number is known as ...................

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Q. A network with bandwidth of 10 Mbps can pass only an average of 15,000 frames per minute with each frame carrying an average of 8,000 bits. What is the throughput of this network ?

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Q. Consider a subnet with 720 routers. If a three-level hierarchy is choosen with eight clusters, each containing 9 regions of 10 routers, then total number of entries in the routing table is ...................

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Q. In a classful addressing, the IP addresses with 0 (zero) as network number:

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Q. In electronic mail, which of the following protocols allows the transfer of multimedia messages?

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Q. A device is sending out data at the rate of 2000 bps. How long does it take to send a file of 1,00,000 characters ?

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Q. Infrared signals can be used for short range communication in a closed area using ................... propagation.

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