APS prevents upper layer protocols and services from being affected by the failure of the active circuit.
The following example with figures and description illustrate how services are protected during a single-chassis APS switchover.
Figure: APS working and protection circuit example shows an example in which the APS working circuit is connected to IOM-1/MDA-1 and the protection circuit is connected to IOM-2/MDA-1. In this example, assume that the working circuit is currently used to transmit and receive data.
Figure: APS working and protection circuit example
