OSI Flashcards
Physical layer specifications
Pin layouts
Voltages
Cable specifications
Hardware: hubs, repeaters, and network interfaces
Data in the Network Layer is broken down into these
Packets
Compression happens in this layer
Presentation (Layer 6)
Connectionless communications
Connection-oriented communications
Flow control
Windowing
Acknowledgements
Transport Layer (Layer 4) specifications
POP3, IMAP, SMTP, Web Browsing (HTTP), Domain Name Service (DNS), File Transfer Protocol (FTP), TELNET, Simple Network Management Protocol (SNMP) are all examples of what layer
Application (Layer 7)
Logical Link Control
Data Link Layer
Ensures every host on the network has a unique address
Logical addressing
Sets up, manages, and tears down sessions between Presentation Layer entities
Provides dialogue control between devices
Coordinates communication between systems
Session Layer (Layer 5)
Layer 3
Network
Hierarchy layers
OSI
BGP
Border gateway protocol
Primarily responsible for getting data from one end-point to another
Network Layer
Routing protocol used to transfer data and information between gateways or autonomous systems
BGP (Border Gateway Protocol)
Communicates directly with the media that transmit bits
Physical
Layer 7
Application
Layer 4
Transport
EPL
Ethernet Private Line
Layer 2
Data Link
Layer 1
Physical
Ensures that data transferred from one system’s Application Layer can be read by the Application Layer on the receiving system
Presentation (Layer 6)
Transfers Ethernet frames from one customer site to another within the Comcast or partner carrier network
EPL (Ethernet Private Line)
OSI
Open Systems Interconnection
Media Access Control (MAC)
Data Link Layer
Routers fall into this layer
Layer 3 (Network Layer)
Logical device addressing
Tracking location of devices on the network
Determining best path for moving data
Network Layer
Layer 6
Presentation
MPEG (Moving Picture Experts Group) - encoding and compression of audio and video data
SSL (Secure Sockets Layer) - encryption for data transmitted on the internet
Presentation (Layer 6)
IPV4
Internet protocol version 4
End-to-end transport services
Establishment of logical connection between sending and destination hosts
Flow Control
Error recovery
Layer 4 (Transport)
Defines electrical and physical specification of devices and relationship between devices and transmission media
Physical
Segments and reassembles data from the upper layers
Transport (Layer 4)
Data translation and code formatting
Presentation (Layer 6)
Oversees movement of data in and out of the communication path using Frames
Data Link Layer
IP (Internet Protocol)
ICMP (Internet Control Message Protocol)
RIP (Router Information Protocol)
Layer 3 (Network Layer)
Presents data to the application layer
Presentation (Layer 6)
Encryption and Decryption
Presentation Layer (Layer 6)
Comcast Business Ethernet falls under this layer
Layer 2 (Data Link)
Identifies where data is headed and where it came from
Data Link Layer
Known as “Protocol Layer”
Data Link Layer
Sends and receives bits on the network
Physical
Layer 5
Session
Ensures that an application’s data is separate from other users’ applications’ data
Layer 5
