Loopback Testing

To configure loopback testing at the SONET/SDH level, use loopback.

loopback

Use to configure the type of loopback at the SONET/SDH layer.
Specify one of the following options:
- local—Loops the data back toward the router
- network—Loops the data toward the network before the data reaches the frame.
Examplehost1(config)#controller sonet 4/0 host1(config-controller)#loopback network
Use the no version to disable loopback.
See loopback.