Which two factors influence the method that is used for media access control?

This course covers configuring and implementation of LAN networks.

IT6201 Data Communications and Networking 1

A media access control is a network data transfer policy that determines how data is transmitted between two computer terminals through a network cable. The media access control policy involves sub-layers of the data link layer 2 in the OSI reference model.

The essence of the MAC protocol is to ensure non-collision and eases the transfer of data packets between two computer terminals. A collision takes place when two or more terminals transmit data/information simultaneously. This leads to a breakdown of communication, which can prove costly for organizations that lean heavily on data transmission.

This network channel through which data is transmitted between terminal nodes to avoid collision has three various ways of accomplishing this purpose. They include:

Carrier sense multiple access with collision avoidance (CSMA/CA)
Carrier sense multiple access with collision detection (CSMA/CD)
Demand priority
Token passing

Carrier sense multiple access with collision avoidance (CSMA/CA) is a media access control policy that regulates how data packets are transmitted between two computer nodes. This method avoids collision by configuring each computer terminal to make a signal before transmission. The signal is carried out by the transmitting computer to avoid a collision.

Multiple access implies that many computers are attempting to transmit data. Collision avoidance means that when a computer node transmitting data states its intention, the other waits at a specific length of time before resending the data.

CSMA/CA is data traffic regulation is slow and adds cost in having each computer node signal its intention before transmitting data. It used only on Apple networks.

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Carrier sense multiple access with collision detection (CSMA/CD) is the opposite of CSMA/CA. Instead of detecting data to transmit signal intention to prevent a collision, it observes the cable to detect the signal before transmitting.

Collision detection means that when a collision is detected by the media access control policy, transmitting by the network stations stops at a random length of time before transmitting starts again.

It is faster than CSMA/CA as it functions in a network station that involves fewer data frames being transmitted. CSMA/CD is not as efficient as CSMA/CA in preventing network collisions. This is because it only detects huge data traffic in the network cable. Huge data traffic increases the possibility of a collision taking place. It is used on the Ethernet network.

The demand priority is an improved version of the Carrier sense multiple access with collision detection (CSMA/CD). This data control policy uses an ‘active hub’ in regulating how a network is accessed. Demand priority requires that the network terminals obtain authorization from the active hub before data can be transmitted.

Another distinct feature of this MAC control policy is that data can be transmitted between the two network terminals at the same time without collision. In the Ethernet media, demand priority directs that data is transmitted directly to the receiving network terminal.‍

This media access control method uses free token passing to prevent a collision. Only a computer that possesses a free token, which is a small data frame, is authorized to transmit. Transmission occurs from a network terminal that has a higher priority than one with a low priority.

Token passing flourishes in an environment where a large number of short data frames are transmitted. This media access control policy is highly efficient in avoiding a collision. Possession of the free token is the only key to transmitting data by a network node. Each terminal holds this free token for a specific amount of time if the network with the high priority does not have data to transmit, the token is passed to the adjoining station in the network.

Media access control regulates how a network is accessed by computer terminals and transmits from one terminal to the other without collision. This is achieved through CSMA/CD, CSMA/CA, demand priority, or Token passing.

Last Updated on January 14, 2021 by Admin

This quiz covers the content in CCNA R&S Introduction to Networks Chapter 4. It is designed to provide an additional opportunity to practice the skills and knowledge presented in the chapter and to prepare for the Chapter Exam.

- bus
- extended star
- ring
- partial mesh
- greater distances per cable run
- lower installation cost
- limited susceptibility to EMI/RFI
- durable connections
- greater bandwidth potential
- easily terminated
- controlling access to media
- transmitting bits across the local media
- performing error detection on received frames
- exchanging frames between nodes over physical network media
- full duplex
- half duplex
- multiplex
- simplex
- STP ——-> This type of copper media is used in industrial or similar environments where there is a lot of interference.
- wireless ——-> This type of media provides the most mobility options.
- optical fiber ——-> This type of media is used for high transmission speed and can also transfer data over long distances.
- coaxial ——-> Traditionally used for television but can now be used in a network to connect the customer location to the wiring of the customer premises.
- They all include the flow control and logical connection fields.
- Ethernet frame header fields contain Layer 3 source and destination addresses.
- They vary depending on protocols.
- They include information on user applications.
- how data is generated by end devices applications
- how the connection between nodes appears to the data link layer
- how signals are encoded by the NICs on end devices
- how nodes share the media
- how the IP protocol forwards the packet to the destination
- CSMA/CD
- priority ordering
- CSMA/CA
- token passing
- addressing ——> This field helps to direct the frame toward its destination.
- error detection ——> This field checks if the frame has been damaged during the transfer.
- type ——> This field is used by the LLC to identify the Layer 3 protocol.
- frame start ——> This field identifies the beginning of a frame.
ITN Chapter 4 Quiz Answers 02
- crossover
- rollover
- straight-through
- fiber-optic
- The end-user device only has an Ethernet NIC.
- The end-user device requires a dedicated connection because of performance requirements.
- The end-user device needs mobility when connecting to the network.
- The end-user device area has a high concentration of RFI.
- crossover
- rollover
- straight-through
- coaxial
- Noted: There are 3 possible answers. You can fill in one of the following in netacad: LIGHT, Light, and light. But you can fill only LIGHT.
ITN Chapter 4 Quiz Answers 01
- 128 kb/s
- 10 Mb/s
- 100 Mb/s
- 1000 Mb/s
- It uses the characteristic of one wave to modify another wave.
- It transmits data signals along with a clock signal which occurs at evenly spaced time durations.
- It generates the electrical, optical, or wireless signals that represent the binary numbers of the frame.
- It converts bits into a predefined code in order to provide a predictable pattern to help distinguish data bits from control bits.
- It requires that some of the branch sites be interconnected through point-to-point links.
- It requires that every site be interconnected to each other through point-to-point links.
- All sites require a hub device that connects to a router.
- The branch sites are connected to a central site through point-to-point links.
- to define the media access processes that are performed by the hardware
- to provide data link layer addressing
- to identify which network layer protocol is being used
- to accept segments and package them into data units that are called packets