Layer Encapsulation Devices or
Name Keywords/Description
# Units Components
Network services for application processes, such as file, print,
7 Application data
messaging, database services
Standard interface to data for the application layer. MIME
6 Presentation data encoding, data encryption, conversion, formatting,
compression
Interhost communication. Establishes, manages and
5 Session data
terminates connection between applications
End-to-end connections and reliability. Segmentation/de-
4 Transport segments
segmentation of data in proper sequence. Flow control
Logical addressing and path determination. Routing.
3 Network packets router
Reporting delivery errors
bridge, switch, Physical addressing and access to media. Two sublayers:
2 Data Link frames
NIC Logical Link Control (LLC) and Media Access Control (MAC)
repeater, hub, Binary transmission signals and encoding. Layout of pins,
1 Physical bits
transceiver voltages, cable specifications, modulation
OSI comparison with TCP/IP Protocol Stack
OSI OSI Layer TCP/IP TCP/IP Layer Encapsulation
TCP/IP Protocols
# Name # Name Units
FTP, HTTP, POP3, IMAP, telnet, SMTP, DNS,
7 Application data
TFTP
4 Application
6 Presentation data
5 Session data
4 Transport 3 Transport segments TCP, UDP
3 Network 2 Internet packets IP
2 Data Link frames
1 Network Access
1 Physical bits