Communicating over the network - part 2 Flashcards
What is communication governed by?
Predetermined rules called protocols
What are protocols specific to?
The characteristics of a conversation?
What is a protocol suite?
A group of inter-related protocols that are necessary to perform a communication function
What are protocols implemented in?
Software and hardware that is loaded on each host and networked device
What does a protocol stack show?
How individual protocols within the suite are implemented on a host
How are protocols viewed in the stack?
As a layered hierarchy, with protocols in the higher levels depending on some functionality defined by the lower levels
What 2 things do the lower levels in the protocol stack do?
Move data across a network and provide functionality to the higher levels of the stack
What do the upper layers of the protocol stack focus on?
The content of the message being sent and the UI
What would the physical layer represent in human communication?
The use of people using their voices
What would the rules layer represent in human communication?
How the conversation is carried out e.g.
- Common language
- Wait your turn
- Signal end of speech
What would the content layer represent in human communication?
The actual words that are spoken e.g. “Wilfried Zaha is the greatest footballer in the world”
Why are network protocols used?
To allow devices to communicate successfully
What is the 1st (4) way a network protocol suite would describe precise requirements and interactions?
The format and structure of a message
What is an example of a network protocol suite describing the format and structure of a message?
“Lets agree that each piece will be 10 letters long”
What is the 2nd (4) way a network protocol suite would describe precise requirements and interactions?
The method by which networking devices share information about pathways and other networks
What is an example of a network protocol suite describing the method by which networking devices share information about pathways and other networks?
“Let’s all agree that if one of our pathways is down, we’ll notify all connected devices”
What is the 3rd (4) way a network protocol suite would describe precise requirements and interactions?
How and when error and system messages are passed between devices
What is an example of a network protocol suite describing how and when error and system messages are passed between devices?
“Let’s all agree that error messages have a unique ID number”
What is the 4th (4) way a network protocol suite would describe precise requirements and interactions?
The setup and termination of data transfer sessions
What is an example of a network protocol suite describing the setup and termination of data transfer sessions?
“Lets all agree that sessions will end after 60s of inactivity”
What does it mean if individual protocols in a stack are proprietary or vendor specific?
One company or vendor controls how the protocol functions.
What is the 1st (2) way companies can use proprietary protocols not owned by them?
Some can be used with permission from the owner
What is the 2nd (2) way companies can use proprietary protocols not owned by them?
Some can only be implemented on equipment manufactured by the proprietary vendor
What is a standard?
A process or protocol that has been endorsed by the networking industry and ratified by a standards organisation
What is the 1st (2) network standards organisation?
Institute of Electrical and Electronics Engineers (IEEE)
What is the 2nd (2) network standards organisation?
The Internet Engineering Task Force (IETF)
How do standards help the development and implementation of protocols?
The ensure that protocols from different manufacturers can work together for efficient communication
If one end of a communication is using a protocol that governs one way communication and a protocol at the other end is assuming two way communication, what is the probably outcome?
No information will be exchanged
What is the 1st (4) protocol in a web server protocol stack?
Application protocol
What is an example of an application protocol in the web server stack
Hypertext transfer protocol HTTP
What does HTTP govern? (1st)
The way a web server and client interact
What does HTTP define (2nd)
The content and formatting of requests and responses exchanged between the client and server
What implements HTTP as part of the application (3rd)
Both the web server and client software
What does HTTP rely on other protocols for (4th)
To govern how messages are sent between client and server
What is the 2nd (4) protocol in a web server protocol stack?
Transport protocol
What is an example of a transport protocol in the web server stack?
Transfer control protocol (TCP)
What doe TCP manage (1st)
The individual conversations between web clients and web servers
What does TCP do with HTTP messages (2nd)
Divides them into smaller pieces, called segments, to be sent to the destination client
What does TCP control (3rd)
The size and rate at which messages are exchanged between the server and the client
What is the 3rd (4) protocol in a web server protocol stack?
Internetwork protocol
What is an example of an Internetwork protocol in the web server stack?
Internet protocol (IP) The most common Internetwork protocol
What are the 4 things in sequence that IP is responsible for?
- Taking the formatted segments from TCP
- Encapsulating them into packets
- Assigning the appropriate address
- Selecting the best path to destination host
What is the 4th (4) protocol in a web server protocol stack?
Network Access Protocol
What is an example of a Network access protocol in a web server stack?
Ethernet
Data link management is the 1st primary function of the network access protocol. What does it do?
Protocols take packets from IP and format them to be transmitted over media
The physical transmission of data on the media is the 2nd primary function of the network access protocol. What is the 1st (2) step of this?
Standards and protocols for physical media govern how signals wil lbe sent over media and how they will be interpreted by the receiving clients
The physical transmission of data on the media is the 2nd primary function of the network access protocol. What is the 2nd (2) step of this?
Transceivers on NICs implement the standards to be used appropriately for media that is being used
What do protocols generally not do?
Describe HOW to accomplish a particular function
Why do protocols generally not describe how to accomplish a function?
So the implementation of a protocol can be technology independent
What is the benefit of a technology independent protocol?
Any device can access a web page stored on any server, using any operating system from anywhere on the internet
How does HTTP remain technology independent?
Doesn’t specify:
What programming language is used to create a browser
Which web server software should be used to serve web pages
What OS the server runs on etc…
What is the 1st (4) benefit of using a layered model?
Assists in protocol design
How does a layered model assist with protocol design?
Protocols that act at a specific layer have defined information that they act upon and defined interfaces to the layers above
What is the 2nd (4) benefit of using a layered model?
Fosters competition because products from different vendors can work together