Network layer
Physical layer
Data link layer
All of these
LAN
MAN
DSL
Telnet
SMTP
DNS
FTP
Data inaccessibility
Data encryption
Data validity
Data security
WAN
Internet
Memory card
CPU
Protocol
Network
Keyboard Layout
Character Encoding System
Software
Standard Font
Dynamic
PAT
NAT
Static
IEEE800
IEEE801
IEEE802
IEEE803
IP
UDP
TCP
HTTP