4.a - OSI Network Model Layers Flashcards

1
Q

Two dominant network model in use

A

The two dominant network models that are used to illustrate networks are OSI and TCP/IP.

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2
Q

OSI Network model

A

Open Systems Interconnection Model, consist of seven layers :
Physical, Data Link, Network, Transport, Session, Presentation, Application.

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3
Q

Memory Aid for the seven OSI layer models

A

Please Do Not Throw Sausage Pizza Away

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4
Q

OSI Layer 1: Physical

A

Concerned with electrical and physical specifications for devices.

At the physical layer, networks are little more than electric signals flowing in wires or radio frequency airwaves.

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5
Q

Example of OSI Physical layer standard

A

• Cabling • RS-232 • T1 • DOCSIS • 802.11aPHY• CDMA • WLAN • LTE

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6
Q

802.11aPHY

A

means the physical layer component of 802.11

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7
Q

OSI Layer 2: Data Link

A

The data link layer in the OSI model focuses on the method of transferring data from one station on a network to another station on the same network.

DOES NOT DEAL WITH ROUTERS

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8
Q

Example of Data link layer standards

A
  • LAN protocol

* 80211.MAC/LLC - a portion of a well-known WI-FI protocols

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9
Q

OSI Layer 3: Network

A

Ensure the delivery of messages from one station to another via one or more networks.
DEALS WITH ROUTERS

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10
Q

Example of protocols at the network layer

A
  • IP protocol
  • IPSec - to authenticate, encapsulate, and encrypt IP traffic between networks
  • ICMP - for communication diagnostics
  • IGMP - to organize multicast group membership
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11
Q

OSI Layer 4: Transport

A

Concerned with the reliability of data transfer between systems.

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12
Q

Example of transport layer

A
  • TCP, https, three-way handshake

* UPD - transfer file protocol, VoIP

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13
Q

OSI Layer 5 : Session

A

Used to control connections that are established between applications on the smae, or different , systems

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14
Q

Example of session layer

A
  • NetBios

* rpc

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15
Q

OSI Layer 6: Presentation

A

The presentation layer in the OSI model is used to translate or transform data from lower layers (session, transport, and so on) into formats that the application layer can work with.

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16
Q

Examples of presentation layer functions include

A
  • Character set translation - ASCII & EBCDIC
  • Encryption/decryption - SSSL,
  • CODECS - to encode, decode, compress, decompress audio and video data streams
17
Q

OSI Layer 7: Application

A

contains programs that communicate directly with the end user.

18
Q

Physical Network Topology

A
  • Star - Separate cable is run from a central location to each computer.
  • Ring - Consists of cabling that runs from one computer to the next.
  • Bus - Consist of a central cable, with connectors along its length that would facilitate “branch “ cables that would be connected to individual computers.
19
Q

Network adaptor

A

or Network interface card, is a device that is directly connected to a computer’s bus and contain one or more connectors to which an Ethernet network cable may be connected.

20
Q

Hub

A

Like a repeater, they propagate packets

21
Q

Gatteway

A

Device that acts as a protocol converter, or performs some other type of transformation of messages.

22
Q

Repeater

A

A device that receives and re transmits the signal on an Ethernet network

23
Q

A bridge

A

a device that is used to interconnect Ethernet networks

24
Q

Switch

A

It’s like a hub, but it listens to traffic, and learn the MAC addresses associated to each port and will send packets only to destinations ports

25
Q

Router

A

A device used to connect two or more logical networks together

26
Q

WI-FI or WLAN

A

permits computers to communicate with each other wirelessly at high speeds over moderate distances from each other

27
Q

WI-FI encryption

A

WPA or WPA2

28
Q

Multicast

A

Multicast is a method for sending IP packets to multiple stations in a one-to-many fashion.