Exam Two Study Guide Flashcards

1
Q

What does the physical layer provide?

A

Responsible for the physical connection between devices. Handles the transmission of raw data, hardware components, signal encoding, data rates and synchronization.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the components of a wireless access point?

A

Radio transceivers, antennas, processor, memory RAM and ROM, power supply, ethernet ports, and firmware.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q
  • What is a NIC and a WLAN NIC?
A

NICs operate at the data link layer and the physical layer of the OSI model, handling network protocols and data formatting for transmission over a network. Wired NIC connects to a network via Ethernet cables and a WLAN NIC uses radio waves instead of physical cables, emabling devices to connect to wireless access points and access networks without being physically tethered.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q
  • Explain the process of encapsulation the physical layer performs.
A

Main role is to convert the data from the data link layer into electrical, optical, or radio signals that can travel over a physical medium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q
  • What are the three basic forms of media?
A

Copper cable (electrical media); fiber-optic cable (optical media); wireless (radio or electromagnetic media)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q
  • What does the physical layer consist of?
A

hardware and transmission components that enable data transfer across a network. It handles the actual transmission of raw bits over a physical medium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
  • What are the organizations that are responsible for physical layer standards?
A
  • International Organization for Standardization (ISO)
  • Institute of Electrical and Electronics Engineers (IEEE)
  • International Telecommunication Union (ITU)
  • American Standards Institute (ANSI)
  • Electronic Industries Alliance (EIA)
  • Telecommunications Industry Association (TIA)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  • The four areas these organizations define and govern of the Physical layer standards?
A

Physical and electrical specifications, data transmission and signaling methods, media and bandwidth specifications, environmental and safety requirements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  • What are the three fundamental functions of the Physical layer?
A

Bit transmission, physical topology, and signal encoding and modulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q
  • How are the bits of the frame transmitted by the physical layer?
A

Bit preparation, encoding, modulation, signal transmission, receiving signals, and decoding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q
  • What is a signaling method?
A

Refers to the technique used to convey information over a communication channel by manipulating signals to represent data.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q
  • How do we represent digital information across a medium?
A

Before transmission, digital information is encoded into a form suitable for the transmission medium. When transmitting digital information over certain types of media (especially wireless), modulation is used to adpat the digital signals to the medium. The encoded and modulated signals are then transmitted across the physical medium, and at the receiving end , the process is reversed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q
  • Which medium uses Manchester encoding?
A

Manchester encoding is particularly used in Ethernet networking technologies, especially for wired networks.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q
  • How do we measure bandwidth?
A

Throughput (bps) = File Size (bits)/Transfer Time (seconds)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q
  • What determines the practical bandwidth of a network?
A

Determined by a combination of the physicial medium, network equipment, protocols, traffic load, latency, configuration, and environmental factors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q
  • What are the three measures for bandwidth quality?
A

Throughput, latency, and jitter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q
  • What is the difference between throughput and goodput?
A

Throughput refers to the total amount of data successfully transmited over a network in a given period, typically measured in bits per second (bps). Goodput refers to the actual usable data transmitted over a network in a given period, also measured in bits per second (bps).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q
  • What type of connector is commonly used in copper cabling?
A

RJ45 is an 8-pin connector that is used primarily for Ethernet networking.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q
  • What are the properties of UTP cabling?
A

UTP consists of pairs of wires twisted together, which reduces electromagnetif interference and crosstalk between pairs. The maximum distance for UTP cabling is generally up to 100 meters (328 feet)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q
  • What is done to the pairs of wires to minimize signal degradation due to electronic noise?
A

Twisted Pair Configuration: each pair of wires is twisted together at a specific rates which helps to cancel out electromagnetic interference because the opposing magnetic fields generated by the current in the wires effectively neutralize each other. Proper pairing and color coding. Use of shieled twisted pair (STP), used in environments where electronic noise is a significant concern.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q
  • What are the other methods listed to limit the susceptibility of copper cables to electronic noise?
A

Shielding, proper installation practices, high-quality materials, reducing loop areas, balancing pairs, grounding and bonding, and the use of ferrite beads.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q
  • What is crosstalk? What is used to limit crosstalk?
A

Crosstalk occurs when a signal from one circuit or channel interferes with a signal in another nearby circuit or channel. Twisted pair design, shielding, balanced transmission, and highquality cables help to prevent crosstalk.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q
  • What changes in the twist from one pair of wires to the next pair to improve the limitation of crosstalk?
A

Varying twist rate/length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q
  • What are some of the elements defined by the TIA/EIA 568A standard?
A

Cable types, performance metrics, wireing schemes, installation pracices, and testing procedures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q
  • What are the three types of Ethernet cables?
A

Twisted pair cables, Coaxial cables, and fiber-optic cables.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q
  • What is a straight-through used for?
A

a straight-through cable is a type of Ethernet cable used primarily to connect different types of network devices in a local area network (LAN). It is typically wired in a way that allows for communication between devices of different roles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q
  • What is a crossover used for and when would I possibly need it?
A

A crossover cable is a type of Ethernet cable specifically designed to connect similar devices directly without the need for an intermediary device like a switch or hub.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q
  • What is a rollover used for?
A

Rollover cables are essential for network administrators when they need direct access to the console ports of networking devices for configuration, management, and troubleshooting.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q
  • What are the other two types of copper cabling besides UTP?
A

Shielded Twisted Pair (STP), which adds shielding to reduce inteference, and Coaxial Cable, which has a central conductor and shielding designed for high-frequency signal transmission.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q
  • What type of materials can be used for fiber optic cabling?
A

Fiber optic cabling utilizes glass (for both single-mode and multi-mode fibers) and plastic (for plastic optical fibers) as the primary materials for its core and cladding. Glass fibers are preferred for long-distance telecommunications due to their superior performance, while plastic fibers are valued for their flexibility and cost-effectiveness in short distance applications.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q
  • What is the encoding method for fiber optic?
A

OOK is the simplest form of modulation used in fiber optics. In this method, the presence of light indicates a binary “1,” while the absence of light represents a binary “0.” This direct representation of data allows for straightforward signal transmission. In PPM, the data is represented by the position of a pulse in time. A pulse is transmitted within a defined time slot, and its position indicates the binary value being sent.FSK involves varying the frequency of the light signal to represent different data values. Different frequencies correspond to different binary values.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q
  • What is meant when I say fiber is used as a ‘light pipe’?
A

it emphasizes its function of efficiently transmitting light signals over long distances through the principles of total internal reflection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q
  • What areas usually implement fiber optic cabling?
A

Fiber optic cabling is implemented across a wide range of areas, including telecommunications, internet service provision, data centers, healthcare, education, industrial applications, smart cities, and broadcasting. Its high bandwidth, low loss, and resistance to interference make it a preferred choice for modern communication and networking needs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q
  • Are two cables needed to transmit and receive light signals? Why?
A

While two separate cables are commonly used for transmitting and receiving light signals in traditional duplex fiber optic communication to facilitate simultaneous bidirectional communication, it is also possible to use a single fiber cable with techniques like Wavelength Division Multiplexing or Time Division Multiplexing. The choice between these approaches depends on the specific application requirements, cost considerations, and infrastructure constraints.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q
  • What are the two types of fiber optic cables?
A

The two primary types of fiber optic cables are Single-Mode Fiber (SMF), designed for long-distance transmission with a small core, and Multi-Mode Fiber (MMF), suited for short-distance applications with a larger core.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q
  • Where would each type of fiber cable be found?
A

Single-Mode Fiber (SMF) is primarily found in long-distance telecommunications, interconnecting data centers, campus networks, and fiber-to-the-home applications due to its capability to transmit data over long distances with low loss. Multi-Mode Fiber (MMF) is more commonly used in local area networks, within data centers for short-distance connections, in broadcasting applications, and in industrial automation settings.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q
  • What colors represent types of fiber cable?
A

Single-Mode Fiber (SMF): Yellow
Multi-Mode Fiber (MMF): Orange (for OM1 and OM2) and Aqua (for OM3 and OM4).
OM5: Light Blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q
  • How do wireless media carry electromagnetic signals?
A

Wireless media carry electromagnetic signals by generating electromagnetic waves that propagate through the air. These signals are transmitted by devices that convert electrical signals into electromagnetic waves and are received by antennas or receivers that convert them back into electrical signals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q
  • What is the major concerns/limitations for wireless signals?
A

Interference, range limitations, security vulnerability, bandwidth limitations, signal attenuation, and latency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q
  • What are the 4 standards for wireless networks?
A
  • IEEE 802.11a: This standard operates in the 5 GHz frequency band and supports data rates up to 54 Mbps
  • IEEE 802.11b: Operating in the 2.4 GHz frequency band, this standard supports data rates up to 11 Mbps.
  • IEEE 802.11g: This standard is also in the 2.4 GHz band and supports data rates up to 54 Mbps.
  • IEEE 802.11n: Operating in both the 2.4 GHz and 5 GHz bands, 802.11n significantly improves throughput, supporting data rates of up to 600 Mbps through the use of MIMO (Multiple Input Multiple Output) technology, which uses multiple antennas for transmission and reception, thereby enhancing performance and range.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q
  • What are the 4 areas physical layer star nards are applied for wireless media?
A
  • Frequency band utilization
  • modulation techniques
  • signal transmission and reception.
  • data rates and throughput
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q
  • What are the two network devices necessary to implement a wireless network?
A

A Wireless Access Ppint (WAP) connects to a wireed network and allows wireless devices to communicate with the wired networks and with each other. A Wireless Network Interface Card (NIC) is installed in a computer or other device to enable it to connect to a wireless network.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q
  • Copper cable and fiber-optic cable are examples of physical media, which is used to carry the communication signal?
A

Copper Cable: This type of cable, which includes twisted pair cables (like Cat5e, Cat6) and coaxial cables, uses electrical signals to transmit data. Copper cables are relatively inexpensive and easy to install but are subject to electromagnetic interference and signal degradation over longer distances. They are commonly used in local area networks (LANs) and for connecting devices like computers, routers, and switches.

Fiber-Optic Cable: Fiber-optic cables use light signals to transmit data through thin strands of glass or plastic. This type of cable provides much higher bandwidth and can transmit data over much longer distances without loss of signal quality compared to copper cables. Fiber optics are immune to electromagnetic interference and offer greater security. They are often used in backbone networks, data centers, and long-distance telecommunications.

44
Q
  • What is the purpose of encoding?
A

The purpose of encoding in networking and data communication is to convert data into a specific format for efficient transmission and storage.

45
Q

What are the 2 basic services the Data Link layer provides?

A

Framing: This service involves encapsulating network layer packets into frames. Framing defines the start and end of each frame, ensuring that the data can be correctly interpreted by the receiving device. It includes adding headers and trailers that contain control information, such as source and destination addresses and error-checking data.

Error Detection and Correction: The Data Link layer is responsible for detecting and correcting errors that may occur during the transmission of frames over the physical medium. It employs various techniques, such as checksums and cyclic redundancy checks (CRC), to identify errors and may request retransmission of corrupted frames to ensure reliable communication

46
Q

List and define the 4 specific terms associated with the Data Link layer.

A

Frame: A data packet encapsulated with header and trailer.
MAC Address: A unique identifier for network interfaces.
Error Detection: Methods to identify errors in data transmission.
Flow Control: Mechanisms to manage data transmission rates.

47
Q

What happens to the frame as it moves from source to destination?

A

The frame is encapsulated, transmitted over the network, possibly modified for routing, and then decapsulated at the destination.

48
Q

What is Media Access Control (MAC) and what does it do?

A

Media Access Control (MAC) is a sublayer of the Data Link layer in the OSI model that manages how devices in a network gain access to the shared medium and transmit data. Its main functions include:

Addressing: Assigns a unique MAC address to each device on the network for identification.

Channel Access: Regulates how devices share the transmission medium, preventing collisions and ensuring orderly access to the channel.

Framing: Prepares data frames for transmission, including adding headers and trailers.

Error Detection: Implements methods to identify errors in transmitted frames, ensuring data integrity.

49
Q

What can the control information tell you?

A

Control information can indicate the source and destination addresses, error-checking data, and frame type, helping to manage data flow and integrity during transmission.

50
Q

List and define the 3 elements of a Data Link Layer Frame.

A

Header: Contains control information, including source and destination MAC addresses, and protocol type. It helps in directing the frame to the correct recipient.

Payload: The actual data being transmitted, which can include upper-layer protocol data.

Trailer: Typically includes error-checking information, such as a Frame Check Sequence (FCS), to detect any errors that may have occurred during transmission.

51
Q

What is the most common physical device that is used for the Data Link Layer?

A

The most common physical device used for the Data Link Layer is a network switch. Switches operate at the Data Link Layer to forward frames based on MAC addresses, enabling communication within a local area network (LAN).

51
Q

List and define the 5 typical field types of an ethernet frame.

A

Preamble: A 7-byte field that helps synchronize the transmission timing between sender and receiver.

Start Frame Delimiter (SFD): A 1-byte field that indicates the start of the frame data.

Destination MAC Address: A 6-byte field specifying the MAC address of the intended recipient.

Source MAC Address: A 6-byte field that contains the MAC address of the sender.

Payload (Data): A variable-length field that carries the actual data being transmitted, typically up to 1500 bytes.

Frame Check Sequence (FCS): A 4-byte field used for error detection, containing a cyclic redundancy check (CRC) value.

52
Q

Describe the two sublayers of the Data Link Layer.

A

Logical Link Control (LLC): This sublayer manages communication between the upper layers (Network Layer) and the lower sublayer (Media Access Control). It provides flow control, error checking, and framing for data packets. LLC also allows multiple network protocols to coexist over the same physical medium.

Media Access Control (MAC): This sublayer controls how devices on a network access the shared medium. It determines the rules for data transmission, including frame addressing, collision detection, and avoidance methods (such as CSMA/CD and CSMA/CA). MAC ensures that frames are sent and received without interference between devices.

53
Q

What are the two functions of the Logical Link Control?

A

Flow Control: LLC manages the rate of data transmission between devices to prevent overwhelming the receiving device. It ensures that the sender does not transmit more data than the receiver can process at any given time.

Error Control: LLC provides mechanisms for error detection and correction. It checks for errors in the transmitted data frames and may request retransmission of corrupted frames to ensure reliable communication.

54
Q

What are the two functions of the Media Access Control sublayer?

A

Frame Delimitation and Addressing: MAC adds headers and trailers to data frames, providing addresses for the source and destination devices. This ensures that frames are properly formatted for transmission over the physical medium.

Medium Access Control: MAC determines how devices on the same network segment access the shared communication medium. It employs methods like Carrier Sense Multiple Access (CSMA) to manage data transmission and prevent collisions.

55
Q

What are the 4 organizations that define the Data Link standards?

A

Institute of Electrical and Electronics Engineers (IEEE): Develops standards for networking protocols, including Ethernet and wireless (e.g., 802.11).

International Organization for Standardization (ISO): Develops global standards for various industries, including networking (e.g., OSI model).

Telecommunications Industry Association (TIA): Creates standards for telecommunications equipment and systems, including wiring standards.

Internet Engineering Task Force (IETF): Develops and promotes voluntary Internet standards, including those relevant to network protocols and data link layer specifications.

56
Q

What analogy is made with the media access control?

A

The analogy commonly made with Media Access Control (MAC) is that of a traffic light system. Just as traffic lights regulate the flow of vehicles at intersections to prevent collisions and ensure smooth traffic flow, MAC protocols manage how multiple devices share the same communication medium to avoid data collisions and coordinate access to the network. This helps maintain orderly communication in a networked environment.

57
Q

What does the method that media access control uses depend on?

A

The method that Media Access Control (MAC) uses depends on the network topology and the protocol being implemented. Factors such as whether the network is a wired or wireless environment, the number of devices sharing the medium, and the nature of the data traffic (e.g., bursty vs. continuous) all influence the choice of MAC method. Common methods include Carrier Sense Multiple Access (CSMA) for wired networks and Token Ring for certain types of local area networks (LANs).

58
Q

What are two examples of controlled media access?

A

Token Ring: A network protocol where a token circulates around the network, granting permission to the device holding it to transmit data. Only the device with the token can send data, preventing collisions.

Polling: In this method, a central controller (master) polls each device in the network to check if it has data to send. Only the polled device can transmit, ensuring orderly access to the communication medium.

59
Q

What are two examples of contention-based media access?

A

Carrier Sense Multiple Access with Collision Detection (CSMA/CD): Used in wired Ethernet networks, this method allows devices to listen to the channel before transmitting. If a collision occurs (two devices transmit simultaneously), they stop, wait a random period, and try again.

Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA): Common in wireless networks like Wi-Fi, this approach allows devices to listen to the channel and use techniques like RTS/CTS (Request to Send/Clear to Send) to minimize the chance of collisions before transmitting data.

60
Q

Why can controlled media access be inefficient?

A

Idle Time: In scenarios where a medium is reserved for a specific device, other devices must wait, leading to underutilization of the medium during idle periods.

Overhead: The protocols governing controlled access can introduce additional overhead from managing access, which can slow down communication and reduce overall network throughput.

61
Q

What is CSMA?

A

CSMA (Carrier Sense Multiple Access) is a network protocol used to manage how data packets are transmitted over a shared communication medium. The key features of CSMA include:

Carrier Sense: Devices listen to the network channel to determine if it is free before attempting to send data.

Collision Handling: If two devices transmit simultaneously, a collision occurs. CSMA protocols often incorporate mechanisms to detect and manage these collisions, typically through techniques like CSMA/CD (Collision Detection) or CSMA/CA (Collision Avoidance).

62
Q

What is a data collision?

A

A data collision occurs in a network when two or more devices attempt to send data packets over the same communication channel simultaneously. This results in the packets interfering with each other, causing them to become corrupted and leading to the loss of the transmitted data. Collision management protocols, such as CSMA/CD or CSMA/CA, are implemented to detect or prevent collisions and ensure reliable data transmission.

63
Q

What is CSMA/CD?

A

CSMA/CD (Carrier Sense Multiple Access with Collision Detection) is a network protocol used to manage access to a shared communication medium. Here’s how it works:

Carrier Sense: A device listens to the channel to determine if it is free before attempting to transmit data.
Multiple Access: Multiple devices can share the same communication medium.
Collision Detection: If two devices transmit simultaneously and a collision occurs, they detect it.
Backoff: After detecting a collision, the devices stop transmitting and wait for a random period before attempting to resend their data.
Primarily used in Ethernet networks

64
Q

What is CSMA/CA?

A

Carrier Sense: A device checks the channel to see if it is free before attempting to transmit data.
Collision Avoidance: Instead of detecting collisions after they occur (like CSMA/CD), CSMA/CA takes proactive steps to avoid collisions.
Request to Send (RTS) and Clear to Send (CTS): Before transmitting data, a device may send an RTS signal to the receiving device. If the receiver is ready, it responds with a CTS signal, indicating the sender can transmit.
Backoff Mechanism: If the channel is busy, devices will wait for a random backoff period before rechecking the channel, reducing the chance of collisions.
CSMA/CA is commonly used in wireless networks like Wi-Fi (IEEE 802.11) to ensure that multiple devices can share the same frequency without interfering with one another.

65
Q

What logical and physical topologies are typically used in networks?

A

Logical Topologies:
Bus Topology: All devices share a single communication line. Data travels in both directions along the bus, and devices listen for messages addressed to them.
Star Topology: All devices connect to a central hub or switch. Data is sent from a device to the hub, which then forwards it to the destination device.
Ring Topology: Each device is connected to two other devices, forming a circular pathway. Data travels in one direction, passing through each device until it reaches its destination.
Mesh Topology: Devices are interconnected, allowing for multiple paths for data to travel. This increases reliability as there are alternative routes if one connection fails.
Physical Topologies:
Star Topology: Physically, devices are connected to a central point (hub or switch) using individual cables.
Bus Topology: All devices connect to a single backbone cable, with terminators at both ends to prevent signal bounce.
Ring Topology: Devices are connected in a circular fashion using cables, forming a closed loop.
Hybrid Topology: A combination of two or more topologies, such as star-bus or star-ring, tailored to the network’s needs.

66
Q

Which type of topology is used to determine the media access control?

A

The logical bus topology is typically used to determine the media access control (MAC) method in networks. In a bus topology, all devices share the same communication line, and the MAC protocol manages how data is transmitted over this shared medium, helping to prevent data collisions and ensuring orderly access. This setup is particularly common in protocols like Carrier Sense Multiple Access (CSMA), which is designed for environments where multiple devices need to communicate over a single channel.

67
Q

What are the three types of media access control can be used in a multi-access topology?

A

Controlled Access: Devices take turns accessing the medium (e.g., Token Ring, Polling).
Contention-Based Access: Devices compete for access (e.g., CSMA/CD, CSMA/CA).
Time-Division Multiple Access (TDMA): Medium is divided into time slots for each device to transmit.

68
Q

How does a data flow in a ring network?

A

In a ring network, data flows in a circular path. Each device is connected to two others, forming a closed loop. When a device wants to send data, it transmits the data packet, which travels in one direction around the ring until it reaches the intended recipient. The recipient device accepts the data, and the packet continues around the ring until it completes the cycle. If the packet is not addressed to any device, it is discarded after a full loop.

69
Q

Which part the network (WAN/LAN) is the data link address used in delivering?

A

The data link address is used in delivering data within a Local Area Network (LAN). It enables communication between devices on the same local network segment, facilitating the transfer of frames between nodes. In contrast, Wide Area Networks (WANs) rely on logical addressing (like IP addresses) for routing data between different networks.

70
Q

What is the difference between Data Link Address and Logical Address?

A

Scope:

Data Link Address: Local network (LAN); identifies devices on the same segment (e.g., MAC address).
Logical Address: Across networks (WAN); used for routing (e.g., IP address).
Format:

Data Link Address: MAC address (hardware identifier).
Logical Address: IP address (network identifier).
Function:

Data Link Address: Facilitates direct communication within a local network.
Logical Address: Enables routing between different networks.

71
Q

Does a point-to-point link need a data link address?

A

No, a point-to-point link does not need a data link address because it connects only two devices directly. Communication occurs without the need for a unique identifier for each device, as both ends of the link can identify each other directly.

72
Q

What is error detection?

A

Error detection is a technique used to identify errors that may occur during data transmission. It involves adding extra bits (redundancy) to the data, which allows the receiving device to check for discrepancies between the sent and received data, ensuring data integrity. Common methods include checksums, cyclic redundancy checks (CRC), and parity bits.

73
Q

Explain the Frame Check Sequence (FCS)

A

The Frame Check Sequence (FCS) is a method used in data link layer protocols to detect errors in transmitted frames. It involves a checksum calculated from the data within the frame and appended to the frame before transmission. Upon receiving the frame, the receiving device recalculates the checksum and compares it to the FCS value. If they match, the frame is considered error-free; if not, the frame is deemed corrupted and typically discarded. FCS helps ensure data integrity in network communications.

74
Q

Do all Data Link protocols support using the FCS to determine errors?

A

Not all Data Link protocols support FCS; some may use different error detection methods or none at all

75
Q

What is the data link address?

A

A data link address (or MAC address) is a unique identifier assigned to network interfaces for communication at the data link layer.

76
Q

How is the data link address expressed?

A

Data link addresses are typically expressed in hexadecimal format, often as six pairs of two-digit numbers (e.g., 00:1A:2B:3C:4D:5E).

77
Q

*

What is the standard used for wireless LANs?

A

The IEEE 802.11 standard is used for wireless LANs.

78
Q

What services are supported by 802.11?

A

802.11 supports services such as authentication, encryption, and framing for data transmission

79
Q

How does the data link layer prepare packets for transmission?

A

The data link layer encapsulates packets into frames, adding headers and trailers, including MAC addresses and FCS

80
Q

Describe the features of a logical ring topology.

A

In a logical ring topology, each device connects to two others, forming a closed loop for data transmission, with data passing in one direction

80
Q

Which protocols are typically used in WANs for media access?

A

Protocols like PPP (Point-to-Point Protocol) and Frame Relay are commonly used in WANs

80
Q

If a node receives a frame and the calculated CRC does not match the CRC in the FCS, what action will the node take?

A

The node will discard the frame, as it indicates an error in transmission

81
Q

Name five layer 2 protocols.

A

Five layer 2 protocols include Ethernet, PPP, HDLC, Frame Relay, and ATM.

82
Q

What are the contents of the payload in a frame?

A

The payload contains the actual data being transmitted, encapsulated by the data link layer

83
Q

What are the IEEE802.3 data encapsulation components?

A

IEEE 802.3 encapsulation components include the preamble, MAC header, payload, Frame Check Sequence (FCS), and the inter-frame gap

83
Q

What is the minimum and maximum size of the ethernet frame field?

A

The minimum size is 64 bytes, and the maximum size is 1518 bytes for Ethernet frames.

84
Q

What is a characteristic of contention-based MAC?

A

Contention-based MAC allows multiple devices to compete for access to the same communication medium, often using protocols like CSMA/CD.

85
Q

Frames less than the minimum are called? Greater than the maximum?What does an Ethernet MAC address consist of (bits and type)?

A

Frames less than the minimum are called “runt frames,” and those greater than the maximum are called “giant frames.” An Ethernet MAC address consists of 48 bits, expressed as 12 hexadecimal digits

86
Q

Know the different components of a MAC address (OUI and Vendor assigned) and where they are located.

A

A MAC address consists of an Organizationally Unique Identifier (OUI) (first 24 bits) and a vendor-assigned identifier (last 24 bits)

86
Q

Know the different methods for denoting a MAC hexadecimal address (‘H’, 0x…)

A

A MAC address can be denoted as 00:1A:2B:3C:4D:5E or in hex format prefixed with 0x (e.g., 0x001A2B3C4D5E).

87
Q

What address (MAC) is used to perform broadcast message? Multicast? Unicast?

A

Broadcast uses the MAC address FF:FF:FF:FF:FF
, multicast uses specific multicast MAC addresses, and unicast uses a unique MAC address for a single recipient.

88
Q

What does the frame in the data link layer encapsulate?

A

The frame encapsulates the data packet from the network layer, adding headers and trailers for delivery

89
Q

Know how a frame is processed.

A

When a frame is received, the MAC checks the address, validates the FCS, and if correct, forwards it to the appropriate layer or device.

90
Q

What is a ‘burned-in address’?

A

A burned-in address is a factory-assigned MAC address that is permanently embedded in the hardware of a network device

91
Q

What is Address Resolution Protocol?

A

Address Resolution Protocol (ARP) resolves IP addresses to MAC addresses on a local network

92
Q

What is Neighborhood Discovery?

A

Neighborhood Discovery is a protocol used to discover other devices on a local network, identifying their IP and MAC addresses

93
Q

Understanding how a switch works, forwards, and builds a MAC address table.

A

A switch forwards frames based on MAC addresses and builds a MAC address table by learning the addresses of devices connected to its ports.

94
Q

What happens if a frame is received that is not included in a switches MAC address table?

A

If the frame’s destination MAC address is not in the table, the switch will flood the frame to all ports except the one it was received on.

95
Q

What are the two variants of cut-through switching?

A

The two variants of cut-through switching are fast-forward and fragment-free switching.

96
Q

What is store-and-forward switching?

A

Store-and-forward switching receives the entire frame before forwarding it, checking for errors before transmission.

97
Q

What is the two memory buffering methods on switches?

A

The two memory buffering methods are shared memory buffering and dedicated memory buffering

98
Q

What is auto-negotiation in speed and duplex settings?

A

Auto-negotiation allows devices to automatically agree on the best speed and duplex mode for communication

99
Q

Know and describe the two types of duplex settings used for communications on Ethernet networks.

A

The two types are half-duplex, where data transmission occurs in both directions but not simultaneously, and full-duplex, where data transmission occurs simultaneously in both directions.

100
Q

What is auto-MDIX?

A