Manualshelf

User manual

ManualsBrandsCONRAD COMPONENTS ManualsScience KitsCourse material Profi Lernpaket Internet of Things 14 years and over
21222324252627282930
What is a port?
When comparing to a postal address, the port would be similar to the front door in
an apartment house. A computer with a unique IP can provide different services
via different ports. You can reach the server via the IP, but you use the port to
choose the service to be used. For example, this can be port 20 for FTP data
transmission or port 23 for a Telnet connection. You can usually select the port
freely; however, there are standardised ports that make handling web applications
easier. A list of standardised ports can be found at
https://de.wikipedia.org/wiki/Liste_der_standardisierten_Ports
What is UDP?
UDP is short for User Datagram Protocol. This is a minimal, connection-free net-
work protocol. Generally, it is more minimalist and simpler than other internet pro-
tocols, such as TCP, which we will deal with later. The comparison is not particu-
larly simple here yet, but you may remember the following regarding the protocol's
properties:
U
UDP is broadcast-capable.
U
It does not review the data for accuracy or correct errors.
U
There is therefore no guarantee that data have been successfully
transmitted.
U
There also is no guarantee that data have not been falsified on the
way or listened in on by third parties.
U
You do not need to establish a connection first. Quick data exchange
is possible.
U
There are barely any transmission delay fluctuations.
U
The format is suitable, e.g., for VoIP (Voice over IP – i.e. phone calls
via internet).
These are the most important basics on the terms for the following projects. The
subject can be dealt with in more detail still, and further information will follow in a
suitable location. First, let us deal with the practical part.
2.1 | Exchanging data between the board und PC by UDP
In this project on the subject of UDP, data are exchanged between the board and
the PC via the WLAN. The prerequisite for this is that your computer has a WLAN
adapter. A program on the PC-side ensures successful receipt of the messages.
You will not need any special hardware setup for this experiment.
The program
When you load the program P04_UDPBasics.ino onto the controller, the controller