The phrase "congested network" refers to a situation when there is too much traffic or data in a network, causing it to become overloaded and slow down. Full definition
If you live in a really congested network area like an apartment complex, you might want to change your Wi - Fi channel to something different than the default to try and get a better signal. (howtogeek.com)
The computers that make up the Net then decide which is the best route for each packet to take, depending on how congested the network is. (newscientist.com)
The more congested a network, greater is the fee. (coinsesame.com)