This read-only BertPattern reports the pattern actually being received (Rx) on this BERT test stream, per its description, as distinct from the Tx pattern being transmitted. An administrator compares this against the expected/transmitted pattern to detect pattern mismatches, which can indicate a misconfiguration or a signal integrity problem on the link. For example, if bertTestStreamMonRxPattern doesn't match the configured Tx pattern, an operator would suspect a wiring or loopback configuration error rather than simple bit errors.