Example: Established Socket

A socket is created by an application running in a host. The application assigns a transport protocol (TCP or UDP) and source and destination addresses to the socket. It identifies sockets by assigning numbers to them.

Note the web server has two sockets opened: one for each web page it is serving. These sockets are differentiated by the destination port numbers.

socket_creation.JPG

One host does not assign the socket number on both sides of the communication channel. The socket numbers assigned to each socket are only used by the host that assigned them. In other words, socket number 1 created on one host may be connected to socket number 5 on another host.

Based on the Well-Known source port numbers assigned to each socket, we can determine sockets 1 and 2 were created by an HTTP server application and socket 3 was created by an SMTP or email server application.

This graphic shows a virtual TCP connection between a client and server. Note the socket numbers are not the same on both sides of the channel. Hosts create, close and number their own sockets.

socket_example.JPG
© 2024 Microchip Technology, Inc.
Notice: ARM and Cortex are the registered trademarks of ARM Limited in the EU and other countries.
Information contained on this site regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer's risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights.