Chapter 2: Network Model

LAYERS OF OSI MODEL

1. physical-transmit individual bits frm 1 node to next
2. data link-transmit frames 1 nodes to next
3. network-delivery of packets from original sources to final destination
4. transport-delivery of message from 1 process to another
5. session-maintains,establishes & synchronizes interaction betw. com. systems
6. presentation-syntax and semantics of information exchanged betw. 2 systems
7. application-provide services to user

TCP/IP MODEL - RELATION - ADDRESS

1. physical - underlying physical network - physical
2. data link - same
3. network - IP & other protocols - logical
4. transpot - UDP,TCP,SCTP - port
5. application - process - specific

Chapter 1:Introduction to Data Communication

DEFINITION: exchange of data betw. 2 devices via some form of transmission medium.

COMPONENTS:

1. message: data(text,no,image,audio,video)
2. sender: devices that send message
3. receiver: devices that receive data
4. medium: physical path for transmission
5. protocol: set of rules that governs data communication

EFFECTIVENESS:

1. delivery
2. accuracy
3. timeliness
4. easy understand
5. noise

DATA FLOW

1. simplex: undirectional(only 1 of 2 devices can transmit or receive)
2. half-duplex: both can transmit and receive but not at same time
3. full-duplex: can transmit and receive simultaneously

MODE OF DATA TRANSMISSION

• parallel
• serial -synchronous,asynchronous