Test 2 Study Guide

CSC3013/BIS3013 Computer Networks and Telecommunications

Fall 2012

Chapter 4: Data Link Layer

MEDIA ACCESS CONTROL

Controlled Access – Polling

Contention – collisions

Relative Performance - crossover-point

ERROR CONTROL

Sources of Error – know each, what causes it, how to prevent it

Error Prevention – methods, equipment and strategies

Error Detection – efficiency issues, parity, checksum, CRC

Error Correction via Retransmission – relative merits, protocols, efficiency considerations.

Forward Error Correction – advantages, costs. Hamming codes.

Error Control in Practice

DATA LINK PROTOCOLS

Asynchronous Transmission – what is it, examples, pro and cons.

Synchronous Transmission – frames, HDLC, Ethernet, PPP

TRANSMISSION EFFICIENCY

Information vs. overhead bits

Definition of transmission efficiency

Effects of frame size on throughput

TRIB computations

Chapter 5: Networks and Transport Layers

TRANSPORT AND NETWORK LAYER PROTOCOLS

Transmission Control Protocol

- protocol fields and purpose

Internet Protocol

- protocol fields and purpose

TRANSPORT LAYER FUNCTIONS

Linking to the Application Layer

- Port addressing

Segmenting

Session Management

- Connection-oriented messaging

- Connectionless-oriented messaging

- Quality-of-service

ADDRESSING

Assigning Addresses

- Types of addresses (Application, Network, and Physical layer addresses)

- ICANN

- Internet Address classes (recognize a address class from an address), significance of classes

- Subnets – meaning, masks, routine

- Dynamically assigning IP address (DHCP)

Address Resolution

- DNS
- Name servers
- hierarchical lookups

ROUTING

Routing tables

Types of Routing

- Centralized
- Static
- Dynamic (distance vector, link state)

Routing Protocols

- Interior routing protocols

- Exterior routing protocols

- BGP, ICMP, RIP
- OSFP

Multicasting
-

TCP/IP Protocol operation

Known Addresses, Same Subnet

Known Addresses, Different Subnet

Unknown Addresses

TCP Connections

TCP/IP and Network Layers

Sample T/F questions

Chapter 4

1. Media access controls refer to the need to control when computers transmit.

Difficulty: Easy

Reference: Media Access Control

2. The data link layer accepts messages from the network layer and controls the hardware that transmits them.

Answer: True

Difficulty: Moderate

Reference: Introduction

3. Only the sender of a data transmission needs to be concerned about the rules or protocols that govern how it communicates with the receiver

Answer: False

Difficulty: Easy

Reference: Introduction

4. Most computer networks managed by a host mainframe computer use contention media access control.

Answer: False

Difficulty: Moderate

Reference: Controlled Access

5. Polling is the process of permitting all clients to transmit or receive at any time.

Answer: False

Difficulty: Moderate

Reference: Controlled Access

6. With roll-call polling, a server polls clients in a consecutive, pre-arranged priority list.

Answer: True

Difficulty: Easy

Reference: Controlled Access

7. Token passing is a term that refers to hub polling, in which one computer starts a poll and passes it to the next computer on a multipoint circuit.

Answer: True

Difficulty: Easy

Reference: Controlled Access

8. With contention, a computer does not have to wait before it can transmit. A computer can transmit at anytime.

Answer: False

Difficulty: Moderate

Reference: Contention

9. Contention is commonly used with Ethernet local area networks.

Difficulty: Easy

Reference: Contention

10. Controlled access MAC approaches work better in a large network with high usage.Answer: True

Difficulty: Easy

Reference: Relative Performance

11. In a network, the type of errors caused during data transmission can be controlled by the network hardware and software.Answer: True

Difficulty: Easy

Reference: Error Control

12. The two categories of network errors are: lost data and delimited data.

Answer: False

Difficulty: Easy

Reference: Error Control

13. If a computer transmits a message containing “ABC” and the destination computer receives “abc” as the message, the message is corrupted.

Answer: True

Difficulty: Moderate

Reference: Error Control

14. In data transmission, data errors are uniformly distributed in time.

Answer: False

Difficulty: Easy

Reference: Error Control

15. Undesirable stray electrical voltage can cause data communication errors.

Answer: True

Difficulty: Moderate

Reference: Sources of Errors

16. Gaussian noise is a special type of attenuation.

Answer: False

Difficulty: Moderate

Reference: Sources of Errors

17. Impulse noise is caused by the thermal agitation of electrons.

Answer: False

Difficulty: Easy

Reference: Sources of Errors

18. Crosstalk occurs when the signal transmitted on one circuit or channel of a transmission system creates an undesired effect in another circuit or channel.

Answer: True

Difficulty: Moderate

Reference: Sources of Errors

19. Attenuation refers to the loss of signal strength.

Answer: True

Difficulty: Easy

Reference: Sources of Errors

20. When the signals from two circuits combine to form a new signal that falls into a frequency band reserved for another signal, this is called, intermodulation noise.

Answer: True

Difficulty: Moderate

Reference: Sources of Errors

21. Eliminating jitter to generate a pure carrier signal in an analog circuit is impossible.

Answer: True

Difficulty: Easy

Reference: Sources of Errors

22. The distance between repeaters or amplifiers on a telephone circuit is determined by the amount of power gained per unit length of the transmission.

Answer: False

Difficulty: Moderate

Reference: Error Prevention

23. When we amplify the signal on an analog circuit, we also amplify any noise that is present on the circuit.

Answer: True

Difficulty: Easy

Reference: Error Prevention

24. For effective error detection and correction, extra error detection “data” must be included with each message

Answer: True

Difficulty: Moderate

Reference: Error Detection

25. In an odd parity-checking scheme, the parity bit is set to make the total number of ones in the byte (including the parity bit) an even number.

26. Parity checking can only detect an error when an even number of bits are switched.

Answer: False

Difficulty: Moderate

Reference: Parity Checking

27. Cyclical redundancy check is one of the most popular polynomial error-checking schemes.

Answer: True

Difficulty: Easy

Reference: Cyclical Redundancy Check

28. The simplest method for error correction is retransmission.

Answer: True

Difficulty: Easy

Reference: Error Correction via Retransmission

29. Another term for stop-and-wait ARQ is sliding window.

Answer: False

Difficulty: Easy

Reference: Continuous ARQ

30. One type of forward error correction is the Hamming code.

Difficulty: Moderate

Reference: How Forward Error Correction Works

31. Forward error correction is commonly used in satellite transmission.

Answer: True

Difficulty: Easy

Reference: Forward Error Correction

32. HDLC is very similar to the SDLC synchronous data link protocol.

Answer: True

Difficulty: Moderate

Reference: High-Level Data Link Control

33. Point-to-point Protocol is a byte-count-oriented protocol.

Answer: True

Difficulty: Easy

Reference: Point-to-Point Protocol

34. Overhead bits are used for error checking and marking the start and end of characters and packets.

Answer: True

Difficulty: Easy

Reference: Transmission Efficiency

35. Transmission efficiency refers to the percentage of bits transmitted without errors.

Answer: False

Difficulty: Moderate

Reference: Transmission Efficiency

Chapter 5

1. Several different protocols exist that specify how network and/or transport layer packets are organized.

Answer: True

Difficulty: Easy

Reference: Transport and Network Layer Protocols

2. TCP/IP is a data link protocol that is used on the Internet.

Answer: False

Difficulty: Moderate

Reference: Transport and Network Layer Protocols

3. The network layer sits directly between the application layer and the data link layer in the Internet five-layer network model.

Answer: False

Difficulty: Easy

Reference: Introduction

4. The network layer is responsible for end-to-end delivery of the message.

Answer: False

Difficulty: Easy

Reference: Introduction

5. The transport layer routes messages thought the network selecting the best path from the source to the destination station.

Answer: False

Difficulty: Easy

Reference: Introduction

6. The transport layer process running on the destination computer, reassembles the fragmented application message before passing it up to the application layer

Answer: True

Difficulty: Moderate

Reference: Introduction

7. Software with multiprotocol stacks refers to the fact that the software supports several different transport/network protocols.

Answer: True

Difficulty: Easy

Reference: Transport and Network Layer Protocols

8. TCP is the network layer protocol used on the Internet today.

Answer: False

Difficulty: Easy

Reference: Transmission Control Protocol

9. IP is responsible for error-free delivery of packets on a TCP/IP network.

Answer: False

Difficulty: Easy

Reference: Internet Protocol

10. The TCP portion of TCP/IP performs linking to the application layer.

Answer: True

Difficulty: Easy

Reference: Transmission Control Protocol

11. The source port identifier in the TCP header tells the TCP software on the destination computer, which application on the destination it should pass the packet to.

Answer: False

Difficulty: Easy

Reference: Linking to the Application Layer

12. TCP includes a sequence number so that the packets can be reassembled at the destination in the correct order.

Answer: True

Difficulty: Moderate

Reference: Transmission Control Protocol

13. The latest version of IP is IPv7, which increases the address space from 128 bits to 256 bits.

Answer: False

Difficulty: Easy

Reference: Internet Protocol

14. To help determine to which application a transmission should be delivered on a particular computer, TCP uses the application layer port addresses to distinguish among many open applications on a computer

Answer: True

Difficulty: Moderate

Reference: Linking to the Application Layer

15. Source port address is the logical address generated by the application layer on the source computer to identify the application, which is sending the data.

Answer: True

Difficulty: Easy

Reference: Linking to the Application Layer

16. The standard port number for Telnet is 53.

Answer: False

Difficulty: Easy

Reference: Linking to the Application Layer

17. Because there is a limit on the length of a frame that the data link layer can transmit from node to node, the transport layer breaks up the message from the application layer into several smaller packets.

Answer: True

Difficulty: Moderate

Reference: Segmenting

18. Connectionless routing sets up a TCP connection, or virtual circuit between a sender and receiver.

Answer: False

Difficulty: Moderate

Reference: Connectionless Messaging

19. TCP/IP operates only as connection-oriented.

Answer: False

Difficulty: Moderate

Reference: Connectionless Messaging

20. Quality of Service routing is a special type of connection-oriented routing in which different connections are assigned different priorities.

Answer: True

Difficulty: Easy

Reference: Quality of Service

21. An example of an application layer address is www.indiana.edu

Answer: True

Difficulty: Easy

Reference: Addressing

22. The network layer address for IP is ten bytes long when using IPv4.

Answer: False

Difficulty: Easy

Reference: Addressing

23. The data link layer address is generally encoded in a network card by the card’s manufacturer.

Answer: True

Difficulty: Easy

Reference: Assigning Addresses

24. IPv4 addresses offer unlimited opportunity for expansion and growth on the Internet.

Answer: False

Difficulty: Easy

Reference: Assigning Addresses

25. Subnet masks tell computers what part of an IP address is to be used to determine whether a destination is in the same subnet or in a different subnet.

Answer: True

Difficulty: Moderate

Reference: Subnets

26. The most common standard for dynamic addressing for TCP/IP networks is Dynamic Host Control Protocol.

Answer: True

Difficulty: Easy

Reference: Dynamic Addressing

27. Translating an application layer address to a network layer address and finally to a data link layer address is called address resolution.

Answer: True

Difficulty: Easy

Reference: Address Resolution

28. Part of the function of address resolution is translating the application layer address of the destination into a network layer address.

Answer: True

Difficulty: Easy

Reference: Address Resolution

29. Domain Name Servers provide the equivalent of directory assistance for application layer addresses.

Answer: True

Difficulty: Easy

Reference: Server Name Resolution

30. An Address Resolution Protocol message is broadcast to all computers in a subnet to find the data link layer address.

Answer: True

Difficulty: Moderate

Reference: Data Link Layer Address Resolution

31. Routing is the process of determining the path or route through the network that a particular message will follow from the sender to the recipient.

Answer: True

Difficulty: Easy

Reference: Routing

32. There are four fundamental approaches to routing: centralized, static routing, dynamic routing, and monitor routing.

Answer: False

Difficulty: Moderate

Reference: Types of Routing

33. When using dynamic routing, routing decisions are always made by a central host or server.

Answer: False

Difficulty: Easy

Reference: Dynamic Routing

34. A hop in a routing calculation is defined as one link or circuit.

Answer: True

Difficulty: Easy

Reference: Dynamic Routing

35. An autonomous system is a network operated by one organization.

Answer: True

Difficulty: Easy

Reference: Routing Protocols

36. A routing protocol used inside an autonomous system is called an exterior routing protocol.

Answer: False

Difficulty: Easy

Reference: Routing Protocols

37. Enhanced Interior Gateway Routing Protocol is a dynamic link state interior routing protocol developed by Cisco.

Answer: True

Difficulty: Moderate

Reference: Routing Protocols

38. A multicast message can be used to send a message to a maximum of two other computers.

Answer: False

Difficulty: Moderate

Reference: Multicasting

Topic revision: r2 - 2012-11-28 - JimSkon
 
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