Usually, devices in a Frame Relay network have 2 main roles: The customer Frame Relay Router and the provider Frame Relay Switch. I like to call them like this because it makes the difference more clear between the 2 roles. One difference between a switch and a router is that, typically, a router makes forwarding decisions based on the Layer 3 address, and a switch based on the Layer 2 address. In Frame Relay, the customer router will receive or create a Layer 3 packet. It will look at its destination address and based on the routing table it will have to forward it over a Frame Relay interface. To do this, it will have to encapsulate the Layer 3 packet into a Layer 2 “frame” before sending it out the Frame Relay interface. The next device on the link is the provider Frame Relay Switch, which will forward the frame based only on the Layer 2 information, without looking at Layer 3. This is why the devices in the provider’s Frame Relay cloud are called Frame Relay Switches.