3.2.4.5.12 OUT_R2/B2 RTS PDU
An outbound proxy implementation MUST NOT accept the OUT_R2/B2 RTS PDU in any state other than B1W. If this condition is not met, this PDU is a protocol error and the outbound proxy MUST treat it as a protocol error as specified in section 3.2.4.5.14.
If this RTS PDU is received in B1W state, the outbound proxy implementation MUST perform the following actions in the sequence given:
Transition the state to opened.
Close the successor OUT channel to the client.