What is a common way hackers attempt to shut down an organization's network?

"One of the more common ways bad actors may attempt to shut down Cisco's network infrastructure is through Denial-of-Service attacks, also known as DoS. These types of attacks occur when hackers flood the network with a high number of requests. These requests overload the servers and prevent them from processing legitimate network traffic from authorized users. The key to remediate Denial-of-Service attacks against Cisco is to quickly identify them and route the traffic they are creating outside of the network. I also employ preventive measures such as firewalls and robust user authentication to prevent DoS attacks from occurring."