BB not accepted—BIS reply requested: Sent in response to a BB (either an LUSTAT bid or an Attach) to indicate that the receiver has sent a BIS request and wishes to terminate the session without processing any more conversations, but without sending an UNBIND. A BIS reply is requested so that the negative response sender can send a normal UNBIND. This sense code is sent only by LUs not supporting change-number-of-session protocols.