This chapter is from the book
Gateways
Any device that translates one data format to another is called a gateway. Some examples of gateways include a router that translates data from one network protocol to another, a bridge that converts between two networking systems, and a software application that converts between two dissimilar formats. The key point about a gateway is that only the data format is translated, not the data itself. In many cases, the gateway functionality is incorporated into another device.