Computer Network
INTERNET
Nuts And Bolts Description
Basic Hardware And Software Components That Make Up The Internet
In Terms Of Networking Infrastructure That Provides Services To Distributed Applications
NUTS And BOLTS Description
CN That Interconnects Billions Of Computing Devices Throughout The World
Hosts Or End systems
They Are Connected Together By Network Of Communication Links And Pocket Switches
Transmission Rate Is Measured In bits/sec
When One End System Wants To Send Data To Another, the Sender End system Segments Data And Add Header To Each Segment. the Resulting Packages Of Information Are Called Packets
Packet Switches
ROUTER - Basically Used For Network Core
Link Layer Switches - Basically Used For Access Network
Sequence Of Communication Links And Packet Switches From Sender End System To receiver End System Known As Route or Path
End Systems Access Internet Through ISP(Internet service Providers)
ISP's That Provide Access To end systems Must Also Be Interconnected To Upper Tier (National And International ISP's)
Upper Tier ISP's Consist Of High speed Routers Interconnected With High speed Fiber Optic Links
Each ISP's (Upper Or Lower) Runs The IP Protocol And Confirms To Certain Naming And Address Conventions
Hosts, Packet Switches And Other Internet Devices Run Protocols That Control Sending And Receiving Of Information. TCP and IP are Two Most Important Protocols In Internet.
IP Protocol Specifies Format Of The Packets That Are Sent And Receiving Among Router And End System.
Internet Standards Are Developed By INTERNET ENGINEERING TASK FORCE(IETF). IETF Standard Documents Are Called Request For Commands(RFC's). RFC's Define Protocols Such As TCP, IP, HTTP(For WEB), SMTP(For e-mail). There Are Are More Than 7000 RFC's exists.
The IEEE 802 LAN/MAN specified The Ethernet And Wireless WIFI Standards
Services Description
Internet Is An Infrastructure That Provides Services To Applications. Applications are said to be Distributed Applications Since they involve multiple end systems that exchange data with each other.
Internet Applications Run On end systems And not on the packet switches in Network Core although packet switches facilitate exchange of data among end systems.
End Systems Attached To The Internet provide A Socket Interface That specifies how a running program on one end system ask the internet infrastructure to deliver the data to a specific destination program running on the another end system.