• Initially set to 0xFFFF by the initiator • Responder does not need to assign RX_ID • RX_ID can be assigned if the exchange is multiplexed
DF_CTL
S_ID D_ID
F_CTL
SEQ_CNT
RX_ID
The N_Port that initiates an exchange is called the Exchange Originator and the N_Port that responds to the exchange is called the Exchange Responder. The OX_ID and RX_ID fields are used by the Exchange Originator and Responder to identify a given exchange:
• When the Exchange Originator initiates an exchange, it assigns an OX_ID, and uses the same OX_ID is used for every frame in the exchange.
• The originator initially sets RX_ID to 0xFFFF. The responder can then assign an RX_ID.
• Typically, the responder does not send RX_ID. RX_ID can be used if the exchange is multiplexed across multiple data paths.