Introduction to Networking Flashcards
Why Networking needed?
After inventing personal computers those computers needed to share resources(share printers, share data storage without maintainingduplicats of same data on different computers)
Reasons that motivated Networking of computer
Share expensive resources
To permit the distribution of workload
Concurrent/parallel computing, client-server computing, fault tolerance
To facilitate the transfer of information
Database transactions, electronic mail and networked distribution of data archives
Data communication
Process of transferring digital data in a reliable and efficient manner.
Data communication model
Binary-> analog-> Binary
How computers connected to network
External or internal Modem
Network interface card(NIC)
What’s network?
Two or more computer systems connected together using data communication link is called network
Computer networks depending on technology, structure are of coverage
Technology-
Peer to peer
Client service
Structure -
Star, bus, ring
Area -
Pan, wan, lan, man
Protocol
Set of agreed rules between communicating parties on how communication is proceed
Peer entities
Entities in the corresponding layers on different computer systems
Interface
Difine which operations and services the lower layer makes available to the adjacent upper layer
Flow control
Speed of the sender may differ from the receiver. In such case both sender and receiver should agree on how to send and receive data without them being lost. Receiver’s should acknowledge receipt of data indicating receiver’s current situation.
Error control
Receiver should tell the sender which message were correctly received or not so that sender may resend them or discard the whole message.
Routing
Function of facilitating a path from a source node on one network to a destination node on another network.
OSI Reference model
7. Applications layer
Provide common interface for different user applications
Information maintained-
User data
Portacol-
Http, pop3, soap
Device-
Gateway
presentation layer
Concerned with the syntax and semantics of the information transmitted
Information maintained-
Message
Portacol-
ASC II, GIF, JPAG
Device-
Gateway
Session layer
Established and manages end-user connections
Eg- allows user on different machines to establish sessions between them
Eg- a session might be used to allow a user to log into a remote time sharing system or to transfer a file between two machines
Information maintained-
_
Portacol-
RPC
Device-
Gateway
Transport layer
Provide the functions necessary to guarantee a reliable network link.
Provide error recovery and flow control between two end points of the network connection.
Insulates upper layers(5-7) from having to deal with the complexity of layers 1 - 3
Information maintained-
Datagrams
Portacol-
TCP, UDP
Device-
Gateway
Network layer
Responsible for establishing maintaining, and terminating network connections
Dose routing and forwarding of information in the network
Information maintained-
Packet
Portacol-
IPV4/IPV6, X 25
Device-
Routers and layer three switches
Data link layer
Responsible for reliability of the physical layer established at layer 1.
Create and recognize frame boundaries
Provide error control between adjacent nodes
Information maintained-
Frame
Protocol-
Token ring ethernet, slip, ppp, x.25
Device-
Switches which forward data packets based on the mqc address,
Bridges
Physical layer
Concerned with transmitting raw bits over a communication channel
Information maintained-
Bit
Protocol-
Token ring ethernet, isdn, dsl, x.25
Device-
NIC, repeated, hubs
TCP/IP (Transmission control protocol/ internet protocol)
Only have 4 layers,
Applications
Transport
Internet
Network access
Physical
