1. Process-to-Process Delivery
Purpose
Ensures
communication between application processes
(not just between hosts).
Data link layer:
Node-to-node
Network layer:
Host-to-host
Transport layer:
Process-to-process
Client–Server Paradigm
Client:
Requests service.
Server:
Provides service.
Communication defined by:
Local host
Local process
Remote host
Remote process
Addressing
IP address:
Identifies the host.
Port number:
Identifies the specific process on that host.
IANA Port Ranges
Range
Type
Control
0–1023
Well-known ports
Controlled by IANA
1024–49151
Registered ports
Registered to avoid duplication
49152–65535
Dynamic/Private
Used temporarily by clients
Socket Address
