Ethernet loopback support for RFC 2544-based benchmarking test

Junos OS supports configuring Ethernet loopback for performing the RFC 2544-based benchmarking test. Ethernet loopback can be used for verifying the connectivity and identifying or isolating faults in a network. This feature can be used for performance measurements where packets are looped back to measuring device. Ethernet loopback is supported in the egress user-to-network interface (UNI) direction for a bridge family configuration.