TCP/IP Model
TCP/IP also known as DARPA or the DOD model has 4 layers
Application or process layer
Transport Layer or host to host
o Protocols are TCP and UDP
o Transmission Control Protocol is full-duplex (both ways at the
same time communication)
o User Datagram Protocol - is simplex (one way communication)
UDP is connectionless or best effort communications
protocol - it does not do error detection/correction,
sequencing, flow control, or preestablished sessions and is
not reliable - has low overhead and is quick not good if
data is essential
Often deployed by real-time or streaming communications
for audio/video
o PORTS
Total of 65,536 ports
Port is an address # that both ends of the communication link
agree on
Socket is Port/IP
0-1,023 are well-known ports or service ports
1,024-49,151 are known as registered software ports - software
products specifically registered with International Assigned
Numbers Authority
49,152-65,535 are random, dynamic or ephemeral ports - used
by random or temporarily by clients as a source port
Internet or Internetworking
Link
3-1-1-2
OSI TCP/IP
1
, Application Application
Presentatio Application
n
Session Application
Transport Transport
Network Internet
Data Link Link
Physical Link
TCP/IP is the most used protocol suite - the whole stack - TCP/IP is a platform
independent protocol based on open standards - can be found in almost
every single operating system - but consumes significant resources and is
easy to hack since it was designed for ease of us rather than security
Can be secured using VPN - VPN adds encryption for privacy, confidentiality,
and authentication and to maintain integrity
Protocols used to establish VPN's are:
PPTP - Point to Point Tunneling Protocol
L2TP - Layer 2 Tunneling Protocol
SSH - Secure Shell - vs Telnet
OpenVPN (w/SSL/TLS)
IPSec - Internet Protocol Security
TCP operates at LAYER 4 (Transport) of the OSI - supports full-duplex,
connection oriented, and employs reliable sessions - it employs a handshake
process between 2 systems to establish a communication session
2
TCP/IP also known as DARPA or the DOD model has 4 layers
Application or process layer
Transport Layer or host to host
o Protocols are TCP and UDP
o Transmission Control Protocol is full-duplex (both ways at the
same time communication)
o User Datagram Protocol - is simplex (one way communication)
UDP is connectionless or best effort communications
protocol - it does not do error detection/correction,
sequencing, flow control, or preestablished sessions and is
not reliable - has low overhead and is quick not good if
data is essential
Often deployed by real-time or streaming communications
for audio/video
o PORTS
Total of 65,536 ports
Port is an address # that both ends of the communication link
agree on
Socket is Port/IP
0-1,023 are well-known ports or service ports
1,024-49,151 are known as registered software ports - software
products specifically registered with International Assigned
Numbers Authority
49,152-65,535 are random, dynamic or ephemeral ports - used
by random or temporarily by clients as a source port
Internet or Internetworking
Link
3-1-1-2
OSI TCP/IP
1
, Application Application
Presentatio Application
n
Session Application
Transport Transport
Network Internet
Data Link Link
Physical Link
TCP/IP is the most used protocol suite - the whole stack - TCP/IP is a platform
independent protocol based on open standards - can be found in almost
every single operating system - but consumes significant resources and is
easy to hack since it was designed for ease of us rather than security
Can be secured using VPN - VPN adds encryption for privacy, confidentiality,
and authentication and to maintain integrity
Protocols used to establish VPN's are:
PPTP - Point to Point Tunneling Protocol
L2TP - Layer 2 Tunneling Protocol
SSH - Secure Shell - vs Telnet
OpenVPN (w/SSL/TLS)
IPSec - Internet Protocol Security
TCP operates at LAYER 4 (Transport) of the OSI - supports full-duplex,
connection oriented, and employs reliable sessions - it employs a handshake
process between 2 systems to establish a communication session
2
