Test: Access Control Protocols - Computer Science Engineering (CSE) MCQ

• TDMA is a multiple access method in which the bandwidth is just one time-shared channel.
•  It can convey 64 kbps to 120 Mbps of information rates.
• TDMA provides higher battery life because it does not transmit data continuously while CDMA constantly transmit the data.

An Ethernet network bridge is a device which connects two different local area networks together into one extended Ethernet. For this both networks must connect using the same Ethernet protocol.

A modem (modulator-demodulator) is a network hardware device that modulates one or more carrier wave signals to encode digital information for transmission and demodulates signals to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data.

In slotted aloha, there are time Throughput Calculation

- Given data:
- Frame size = 200 bits
- Bandwidth = 200 Kbps
- Frames per second = 250

- To calculate the throughput, we need to find the efficiency of the system.

- Efficiency of slotted ALOHA system = S * e^(-S), where S is the offered load.

- Offered load (S) = (Frames per second) * (Frame size / Bandwidth)
= 250 * (200 / 200,000)
= 0.25

- Efficiency = 0.25 * e^(-0.25)
≈ 0.2212

- Throughput = Efficiency * Bandwidth
= 0.2212 * 200 Kbps
≈ 44.24 Kbps

- Throughput in frames per second = Throughput / Frame size
= 44.24 Kbps / 200 bits
≈ 0.2212 frames per second

- Converting frames per second to frames per second:
0.2212 frames per second ≈ 49 frames per second

Therefore, the throughput of the system is approximately 49 frames per second. So, the correct answer is A: 49.slots for the stations to transmit the data. Stations can transmit data in time slots. Stations have to wait for their time slots to transmit the data.

Network topology is a schematic description of a network arrangement, connecting various nodes(sender and receiver) through lines of connection.
Common network topologies used in the computer network is as shown:

Conclusion: Cap is not a topology in the computer field.

• There are many networks that exist often with different hardware and software
• It is needed to connected devices on one network with devices on another network
• To connect such incompatible networks, necessary translation in terms of hardware and software is required, the gateway does this task
• A file server is a computer attached to a network that provides a location for shared disk access that can be accessed by the workstations through a shared link
• Printer server is a device that connects printers to client computers over a network
• The Utility Server runs a number of utility applications that support or enhance the component applications facilitating a complete single box solution

B = 10⁸ bits/sec
d = 1 km
Round trip distance = 2 km
To detect a collision, the sender must be transmitting when it receives the collision signal so that it can transmit again.

There are three generations in cellular telephony.

• First Generation: It was designed for voice communication using analog signals. Example: AMPS (Advanced mobile phone system) is one of the leading analog cellular system. It uses FDMA to separate channels in a link. AMPS operates in the ISM 800 MHz band.
• Second Generation: To provide higher quality mobile voice communication, these generation of cellular phone are required. These are used for digital voice communication. Example: D- AMPS, CDMA, GSM. The product of evolution of analog AMPS into a digital system is digital AMPS. D-AMPS uses TDMA and FDMA. GSM stands for global system for mobile communication. It provides duplex communication by using two digital bands.
• Third generation: It refers to a combination of technologies that provide a variety of services. It can provide both digital data and voice communication. Main goal of third generation cellular telephony is to provide universal personal communication. These are based on broadband CDMA. Example: IMT-DS, IMT-MC etc

Data:
L = size of frame
BW → bandwidth = 20 × 10⁶ b/s
T_p → propagation time = 40 μs = 40 × 10-6 s
T_t → transmission time
Formula:
For CSMA/CD,
Tt ≥ 2 × T_p

Calculation:

L ≥ 2 × 40 × 10^-6 × 20 × 10⁶
L ≥ 1600 bits
L ≥ 200 bytes
L_min = 200 bytes
Therefore, the minimum size of a frame in the network is 200 bytes. 

• TDMA is a multiple access method in which the bandwidth is just one time-shared channel.
•  It can convey 64 kbps to 120 Mbps of information rates.
• TDMA provides higher battery life because it does not transmit data continuously while CDMA constantly transmit the data.