week 2 : Introduction cont. & Network Models

Introduction cont.
Intranet vs. Extranet
Intranet is a LAN network that open only inside the organization
Extranet is a LAN network that open only for user outside the organization and allow user to access the network through the internet

Protocols and Standards (Protocols must have standards)
The key elements of protocol
- Syntax(language)
- Semantics
-Timing

Types of standards for Protocols
- Formal standards (developed by industy or goverment)
- De-facto standards(developed by big company)

Major Standard Bodies
- ISO (develop OSI)
- ITU-T (formal name - CCITT)
- ANSI (approve standard)
- IEEE
- IETF
-W3C

Network Models
Implementation of Communication Function
- Single layer
Put everything in one modul, if have something wrong and it already fix. The entire network need to be checked again
- Multi layer
Solve the problem that Single layer have, if it have something wrong in any layer it can modify and fix just the layer that has problem

OSI Model
- Application (providing service to user)
- Presentation (translation compression and encyption)
- Session (dialog control and synchronization)
- Transport (send program data from machine to another program on another machine)
- Network (send frame from source host to the destination host)
- Data link (moving frame from node to node)
- Physical (just send the data and move data from computer to target computer)