Modules 4-7 Flashcards
What is layer 4 of the OSI model?
Transport layer. Manages end-to-end communications.
- manages transmission speeds
- performs error control, ensuring data is received in one piece and requests retransmission if errors occurred.
What is layer 5 of the OSI model?
Session layer. Responsible for opening and closing connections - the time between opening and closing a communication is called a session.
- allows a connection to stay open long enough for data transmission to occur, and then closes it when required to prevent unnecessary resource consumption.
- manages data using checkpoints - if a 100mb file is being transferred, checkpoints can be set at every 5mb, for example, so that if the system crashes, the transfer can be resumed where it left off at the last checkpoint once a session is re-established.
What is layer 6 of the OSI model?
Presentation layer. Prepares data for use by the application layer.
- translates data for the end user or end system to understand.
- if encrypted communication is being used, encryption is either added or decoded.
- if moving down the chain, data is compressed to pass on to the session layer. This improves speed and efficiency by minimising the amount of data requiring transport.
What is layer 7 of the OSI model?
Application layer - presented to the end user/system. Client-side communication.
Which three layers of the OSI model map into to application layer of TCP/IP?
Application, presentation and session.
Which address does a switch use to build the MAC address table?
Source MAC address. Initially, the MAC Address Table of the Switch is empty.It only gets populated when a frame is received.
What four functions does a switch typically have?
- Learning
- Flooding
- Forwarding
- Filtering
What does a switch do when there is no entry in the MAC address table for a destination?
It leaves the Switch with only one option: duplicate and flood the frame out all ports. The frame is duplicated out all ports, except the port it came in on – this is an example of the Switch performing its filteringfunction.
When the correct host receives the frame and realises they indeed are the intended recipient, they will accept the frame and generate a response. Whenthe response arrives on the Switch, another MAC Address Table mapping can be learned: Port 2 contains the MAC address bbbb.bbbb.bbbb.
What three elements do all communication methods have in common?
Message source, destination and a transmission medium.
What is layer 1 of the OSI model?
Physical. Converts data into a bit stream to carry it across physical network components. Both devices in the communication must agree on a signal convention.
What is layer 2 of the OSI model?
Data link layer. Responsible for :
- intranetwork communications - unlike the Network Layer (3), which works with the internetwork
- When data is moving from top to bottom, layer 2 takes packets from layer 3 and segments them into frames.
- flow and error control.
What is layer 3 of the OSI model?
Network. Facilitates data transfer between two different network, routing data and finding the most efficient path. If the devices are on the same network, this layer isn’t required.
- if moving down the chain, it breaks up segments from layer 4 into packets to pass on to layer 2
- if moving up the chain, it reassembles packets to pass on to layer 4.
Which two applications are suitable for deploying coaxial cables?
- to connect various components in a satellite communication system
- to connect network devices in backbone networks
- to connect a TV set to the wall plug at home
- to connect data centres with high bandwidth requirements over long distances
- to connect PCs in an office
- to connect various components in a satellite communication system
- to connect a TV set to the wall plug at home
“Coaxial cable is the kind of copper cable used by cable TV companies. It is used to connect TV sets to the wall jacks that are connected to a cable TV company. It is also used for connecting the various components which make up satellite communication systems.” - https://itexamanswers.net/question/which-two-applications-are-suitable-for-deploying-coaxial-cables-choose-two
Which type of network cable is commonly used in backbone networks and telephone companies?
- fiber-optic
- shielded twisted-pair
- coaxial
- twisted-pair
Fiber-optic cables are ideal for backbone networks and telecommunication infrastructure due to their ability to transmit large amounts of data over long distances with minimal signal loss.
Fiber-optic cables transmit data using light signals that travel through tiny glass or plastic fibers. They provide high bandwidth, long-distance transmission capabilities, and immunity to electromagnetic interference. - https://brainly.com/question/32161715#
