OSI Model Flashcards

Background network info. Not required for exam but helps with understanding Sec+ topics.

1
Q
  1. Physical Layer
A

Concerned with transmission and reception of the unstructured raw bit stream over the physical medium.

Physical structure:

  • Cables
  • Hubs

Primary device - hub

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q
  1. Data Link Layer
A

Provides node-to-node data transfer over the physical layer.

Frame - primary protocol data unit, container for single n/w packet and contains MAC address.

2 sublayers:

  1. Medium Access Control (MAC) Layer - controls a device’s access to n/w and permission to transmit data.
  2. Logical Link Control (LLC) Layer - identifies and encapsulates n/w layer protocols

Central devices: Switch, Bridge, WAP

Central protocols: PPP/SLIP

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

Controls the operations of the subnet, deciding which physical path the data takes.

Provides functional and procedural means to xfr packets from one node to another network’s node.

Central device: Router

Central protocol: IP/IPX/ICMP

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

Ensures that messages are delivered error-free, in sequence, and with no lossess or duplications.

TCP - Host to Host, Flow Control

Central protocols: TCP/SPX/UDP

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

Controls dialogue between computers

Establishes, manages and terminates connections between a local and remote machine

Synch & send to ports (logical ports)

Central device: logical ports

Central Protocols: RPC/SQL/NFS/NetBIOS names

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q
  1. Presentation Layer
A

Formats the data to be presented to the Application layer. Viewed as the translator for the network.

Syntax layer - encrypt & decrypt (if needed)

Central protocols: JPEG/ACII/EBDIC/TIFF/GIF/PICT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
  1. Application Layer
A

Serves as the window for users and application processes to access the network service.

End User Layer - program that opens what was sent or creates what will be sent.

Protocols: (E)SMTP/Telnet/FTP/DNS/DHCP/SNMP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

OSI Model

A

Open Systems Interconnection model

Conceptual model that standardizes communications functions of telecom or computing systems.

Goals:

  • Interoperability of diverse systems
  • Standardized communications protocols

Comprised of 7 layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

OSI Model Layers

A
  1. Application layer
  2. Presentation layer
  3. Session layer
  4. Transport layer
  5. Network layer
  6. Data layer
  7. Physical layer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly