A coupling (or a coupler) is a mechanism for connecting rolling stock in a train. The design of the coupler is standard, and is almost as important as the track gauge, since flexibility and convenience are maximised if all rolling stock can be coupled together.
In computing, a denial-of-service ( DoS) attack is an attempt to make a machine or network resource unavailable to its intended users, such as to temporarily or indefinitely interrupt or suspend services of a host connected to the Internet. A distributed denial-of-service ( DDoS) is where the attack source is more than one–and often thousands of-unique IP addresses.
