Understanding Loopback Testing

Layer 1 to 4 loopbacks (MAC address, IP address and port swap frame reflection) enable remote QoS testing Ethernet, IP and triple-play services. You can establish loopbacks using any of the following combination of parameters:

• The source and/or destination MAC address
• The VLAN ID
• The source and/or destination IP address
• The source and/or destination UDP/TCP ports
• The service level

Loopbacks can be performed either in-band or out-of-band, thereby not impacting customer traffic while tests are being performed.

The Cisco Provider Connectivity Assurance Sensor Control supports the following two types of loopbacks:

• Local (or Private) Loopback: Loops back all traffic matching the custom loopback parameters you define
• Remotely-Controlled Loopback: Loops back traffic upon the reception of a predefined frame type from a JDSU/Acterna™ test set