Technical data

TCP/IP Network Basics 7
Agilent Connectivity Guide 171
sender re-sends the packet. This figure shows a network in which the
source and destination are using TCP and summarizes the steps to use
TCP for communication between hosts.
User Datagram Protocol (UDP) User Datagram Protocol (UDP) is
used for connectionless, non-guaranteed communication. Unlike TDP,
UDP does not set up a connection and does not use acknowledgements.
Instead, UDP sends out packets without waiting for acknowledgement
from the destination.
The Application Layer
The Application Layer is the layer where requests for data or services
are processed. Applications at this layer are waiting for requests to
process and all applications are “listening” at their respective
port. The
Application Layer has two protocols:
• File Transfer Protocol (FTP)
Figure 59 TCP Comunication
Router
Source Destination
Steps
1. Source sends a packet to destination to set up communication.
2. Destination sends acknowledgement to establish communication.
3. Source sends another packet that confirms connection.
4. Source sends a data packet and waits for destination acknowledgement.
5. If acknowledgement is not received, source re-sends the packet.
If acknowledgement is received, source sends the next packet.
TCP Communication