ATM Quiz - Introduction to Asynchronous Transfer Mode

1 What is the fixed size of an ATM cell?

A. 48 bytes

B. 53 bytes

C. 64 bytes

D. 128 bytes

2 In an ATM cell, how many bytes are allocated to the header and payload respectively?

A. 5 bytes header, 48 bytes payload

B. 8 bytes header, 45 bytes payload

C. 10 bytes header, 43 bytes payload

D. 3 bytes header, 50 bytes payload

3 What does the VPI field represent in an ATM cell header?

A. Virtual Channel Identifier

B. Virtual Path Identifier

C. Variable Packet Index

D. Virtual Protocol Interface

4 Which ATM Adaptation Layer (AAL) is designed for Constant Bit Rate (CBR) services such as voice and uncompressed video?

A. AAL1

B. AAL2

C. AAL3/4

D. AAL5

5 What is the primary difference between UNI and NNI cell header formats?

A. UNI has a 4-bit GFC field while NNI uses these bits for additional VPI bits

B. NNI has a larger payload size than UNI

C. UNI uses 16-bit VCI while NNI uses 8-bit VCI

D. NNI includes error correction in the payload while UNI does not

6 Which ATM service category provides guaranteed bandwidth with constant bit rate and is suitable for real-time applications?

A. Available Bit Rate (ABR)

B. Unspecified Bit Rate (UBR)

C. Variable Bit Rate (VBR)

D. Constant Bit Rate (CBR)

7 What is the function of the CLP (Cell Loss Priority) bit in the ATM header?

A. It indicates the type of payload (user data or control data)

B. It determines the virtual circuit identifier

C. It marks cells that can be discarded during network congestion

D. It controls the generic flow between user and network

8 Which layer in the ATM protocol reference model is responsible for segmentation and reassembly of data?

A. Physical Layer

B. ATM Layer

C. ATM Adaptation Layer (AAL)

D. Network Layer

9 What is the relationship between Virtual Paths (VP) and Virtual Channels (VC) in ATM?

A. A Virtual Path contains multiple Virtual Channels

B. A Virtual Channel contains multiple Virtual Paths

C. They are independent and parallel concepts

D. Virtual Paths are used only in UNI while Virtual Channels are used only in NNI

10 Which AAL type is commonly used for IP over ATM and LAN Emulation due to its simplicity and low overhead?

A. AAL1

B. AAL2

C. AAL3/4

D. AAL5

11 What is the purpose of the HEC (Header Error Control) field in the ATM cell header?

A. To encrypt the payload data for security

B. To detect and correct errors in the header and perform cell delineation

C. To identify the type of service (CBR, VBR, etc.)

D. To control the flow rate between sender and receiver

12 What is the main advantage of using fixed-size cells in ATM compared to variable-length packets in traditional packet switching?

A. Higher data compression ratios

B. Predictable processing time, low latency, and efficient hardware switching suitable for real-time traffic

C. Ability to carry larger amounts of data per unit

D. Reduced need for error checking mechanisms