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CHAPTER 1 1.3 - Interpret Reference Model of OSI and TCP/IP - Coggle…
CHAPTER 1
1.3 - Interpret Reference Model of OSI and TCP/IP
Communication Fundamentals
Main Elements of Data Communication Systems
Message - Information to be communicated which includes texts, pictures, audio, video and etc
Sender - Device which sends the data messages. For an example computer, workstation, telephone handset and etc.
Receiver - Device which receives the data messages
Transmission Medium - Physical path by which a message travel from sender to receiver.
EX : twisted-pair wire, coaxial cable, radio waves
Protocol - Set of rules that governs the data communications.
Rules Establishment
Protocols that are necessary for effective communication :
An identified sender and receiver
Common language and grammar
Speed and timing of delivery
Confirmation or acknowledgement requirements
Protocols used in network communications :
MESSAGE ENCODING
Encoding between hosts must be in appropriate format.
Messages are first converted into bits by the sending hosts.
Each bit is encoded into a pattern of sounds, light waves, or electrical impulses depending on the networks.
Destination host receives and decodes the signals in order to interpret the message.
MESSAGE DELIVERY OPTIONS
MESSAGE FORMATTING & ENCAPSULATION
Agreed format for letters and addressing letters which is required for proper delivery.
Putting the letters into the addressed envelope (ENCAPSULATION)
Each computer message is encapsulated in specific format, called frame before its send over the network.
Frame acts like an envelope providing destination address & source address
MESSAGE TIMING
Access Method
Flow Control
Response Timeout
MESSAGE SIZE
Each piece is sent in a separate frame.
Each frame has its own addressing information.
A receiving host will reconstruct multiple frames into the original message
NETWORK PROTOCOLS
Defines as a common format and set of rules for exchanging messages between devices.
Ex : Hypertext Transfer Protocol (HTTP) , Internet Protocol (IP)
Communication Methods
Have three elements :
Source (Sender) - Message sources are people, or electronic devices , that needs to communicate.
Destination (Receiver) - Receives the message and interprets it.
Channel (Media) - Provides pathway over which the message can travel from source to destination.
ROLE OF PROTOCOLS
How the message is formatted
Process by which networking device share information about pathways with other networks.
How and when error system messages are passed between devices.
The setup and termination of data transfer sessions.
PROTOCOL INTERACTION
Communication between a web server and web client.
HTTP - An application protocol that governs the way web server and a web client interact.
TCP - Transport protocol that manages the individual conversations.
IP - Encapsulates the TCP segments into packets, assigns addresses, and delivers to the destination host.
Ethernet - Allows communication over a data link and the physical transmission of data
Benefits of Using a Layered Model
Assisting in protocol design since protocols at each layer have defined functions.
Fostering competition because products from different vendors can work together.
Providing a common language to describe networking functions and capabilities.
