Each station then waits a random amount of time and tries to send its packet again. After 16 consecutive failed attempts, the original application that sent it must start again. As more people try to use the network, the number of collisions, errors, and subsequent retransmits grows quickly, causing a snowball effect. Collisions are normal occurrences, but too many can slow the network. When more than 50 percent of the total network bandwidth is used, collision rates begin to cause congestion.
Files take longer to print, applications take longer to open, and users are forced to wait.
At 60 percent or higher, the network can slow dramatically or even shut down. Shared Ethernet is like a single-lane highway with a 10 Mbps speed limit. Switched Ethernet look likes a multilane highway with a speed limit of 10 Mbps in each lane. Switched Fast Ethernet also would be a multilane highway, but with a speed limit of 100 Mbps in each lane. Switched Gigabit Ethernet would have even more lanes, with a speed limit of 1000 Mbps in each lane.