Final answer:
In an SCTP association, upon receiving a SHUTDOWN chunk while in the ESTABLISHED state and with no data to send, the host responds with a SHUTDOWN ACK chunk and then transitions to the SHUTDOWN-ACK-SENT state, leading to a graceful termination of the association.
Step-by-step explanation:
When an SCTP (Stream Control Transmission Protocol) association is in the ESTABLISHED state and it receives a SHUTDOWN chunk, the host must transition to the SHUTDOWN-RECEIVED state if there are no outstanding or pending data to be sent. Since the host does not have any data to send, it should respond with a SHUTDOWN ACK chunk and then transition to the SHUTDOWN-ACK-SENT state. Finally, upon receiving the SHUTDOWN COMPLETE chunk from the peer, the association is gracefully terminated, and the host moves to the CLOSED state.
When an SCTP association is in the ESTABLISHED state and receives a SHUTDOWN chunk, the host needs to acknowledge the receipt of the chunk by sending a SHUTDOWN COMPLETE chunk. This indicates that the host agrees to shutdown the association. However, since there are no outstanding or pending data, the host can immediately proceed to close the association.