Protocol level:

1. TCP_SENDSYN
   A SYN packet has been sent from the specified TCP socket.

2. TCP_RECVSYN
   A SYN packet has been received to the specified TCP socket.

3. TCP_SENDSYNACK
   A SYN-ACK packet has been sent from the specified TCP socket.

4. TCP_RECVSYNACK
   A SYN-ACK packet has been received to the specified TCP socket.

5. TCP_SENDACK
   An ACK packet has been sent from the specified TCP socket.

6. TCP_RECVACK
   An ACK packet has been received to the specified TCP socket.

7. TCP_SEND
   The specified amount of data is being sent from the specified TCP socket.

8. TCP_SENDPACKET
   A fragmented/whole (unspecified) TCP packet is being queued for sending in the specified TCP socket.

9. TCP_RECEIVE
   The specified amount of data (processed) is being received to the specified TCP socket.

10. TCP_RECEIVEPACKET
    A fragmented/whole (specified) TCP packet has been received to the specified TCP socket and is queued for processing.

11. TCP_RECV_URGENTDATA
    The specified amount of data (processed) is being received to the specified TCP socket. The packet carries the URG (urgent) flag and is processed before other non-urgent data.

12. TCP_DISCONNECT
    A TCP socket has disconnected from its target.

13. UDP_PUSHPENDINGFRAMES
    A UDP socket is pushing all of its pending frames to a specified socket buffer.

14. UDP_FLUSHPENDINGFRAMES
    There has been a ``cork'' in the specified UDP socket and therefore all of the pending frames are being flushed immediately.

15. UDP_QUEUESOCKETBUFFER
    A UDP socket is queueing IP packets received from a specified socket buffer for processing.

16. UDP_RECEIVE
    The specified amount of data (processed) is being received to the specified UDP socket.

17. UDP_SEND
    The specified amount of data is being sent from the specified UDP socket.

18. UDP_CONNECT
    A UDP socket has connected to its target using the UDP protocol.

19. UDP_DISCONNECT
    A UDP socket has disconnected from its target.

20. ICMP_SEND
    An ICMP packet, containing constant data (specified as enumerated code types), is being sent.

21. ICMP_REPLY
    An ICMP packet reply packet is being sent back to the ICMP packet sender.

22. ICMP_RECEIVE
    An ICMP packet, containing constant data (specified as enumerated code types), has been received.

23. ICMP_PUSHPENDINGFRAMES
    An ICMP socket is pushing all of its pending frames to a specified socket buffer.