This MIB module provides information about Voice Enabled ATM and Frame Relay Links used by the Cisco Switched voice protocol. The Cisco Switched voice protocol passes the default MAC address for its node to the next node in the path, in both call setup messages and keepalive requests and responses. This MAC address is stored at the remote node to identify where the incoming pvc originates. This information is then used by the Cisco Voice Manager Application to determine the voice network topology.