OSI model: Open System
Interconnection model. This
model has 7 layers-vertical
stack of 7 layers.
Upper layer: software that provides
network services-like encryption and
connection management.
Lower layer: hardware orientated
functions: routing, addressing and
flow control.
1. Application: SMTP,
FTP, Telnet, HTTP
2. Presentation:
format data(ascii) and
encryption
3. Session:
start and
stop session
4. Transport: TCP,
port numbers
5. Network: IP addresses,
routers
6. Data link: mac addresses
and switches
7. Physical: cables, network,
ethernet
TCP/IP model: transmission control
protocol/internet protocol. This model has 4
layers: application, transport, internet and
link
Application: includes
high level protocols-
FTP, HTTP, SMTP, DNS
Transport: ensures reliable arrival of
messages and provides error checking
mechanisms and data flow controls
Internet: packs data into data
packets (datagrams). Each
packets contains a source and
destination address-IP address.
Uses several protocols for routing
and delivering packets.
Link: defines how datagrams
(like packets) can be passed
in a network.