network congestion explanation (bregman-arie#379)

Add explanation of network congestion and its causes. 
Provide recommendations for preventing and managing network congestion.

README.md

@@ -614,6 +614,10 @@ Throughput. To have a good throughput, the upload stream should be routed to an
 
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 <summary>What is Network Congestion? What can cause it?</summary><br><b>
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+Network congestion occurs when there is too much data to transmit on a network and it doesn't have enough capacity to handle the demand. </br>
+This can lead to increased latency and packet loss. The causes can be multiple, such as high network usage, large file transfers, malware, hardware issues, or network design problems. </br>
+To prevent network congestion, it's important to monitor your network usage and implement strategies to limit or manage the demand.
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