A reactive mechanism for in-situ operation, administration, and maintenance (IOAM) traffic is provided. In one embodiment, a method is provided that includes assigning a plurality of discriminator identifiers associated with a plurality of discriminators. Each discriminator is mapped to a specified action. The method includes receiving a data packet that includes an IOAM header comprising telemetry data associated with the data packet and a bidirectional forwarding detection (BFD) field that includes a specified discriminator identifier. The method further includes determining whether the specified discriminator identifier matches one of the plurality of discriminator identifiers, and, upon determining that the specified discriminator identifier matches a first discriminator identifier of the plurality of discriminator identifiers, the method includes initiating a seamless bidirectional forwarding detection (S-BFD) reflector session to transmit a response packet according to a first action mapped to a first discriminator associated with the first discriminator identifier.