An outbound proxy implementation MUST NOT accept the OUT_R1/A5 RTS PDU in any state other than opened. If it is received in any other state, the outbound proxy MUST treat this PDU as a protocol error as specified in section

If this RTS PDU is received in opened state, the outbound proxy implementation MUST send the OUT_R1/A6 RTS PDU to the client on the default OUT channel. The OUT R1/A6 RTS PDU is initialized using the elements of the OUT R1/A5 RTS PDU.  The state remains unchanged.