Spin Server Rollover Usage Example

The diagram below shows the exchange of messages over time between a member and Cboe’s Multicast PITCH feed and spin server during rollover.

At time 1, the member has no state of the book and desires to become current. The member caches the received Multicast PITCH messages (sequences 4,294,967,294 and 4,294,967,295) for later use. Since the member has no book, they cannot yet be applied.

At time 5, the member has successfully logged into the Spin Server and has cached another message, sequence 1 (the sequence number has rolled over).

At time 7, the member receives Spin Image Available message which indicates that the spin server is capable of giving them a spin of all open orders as of sequence 4,294,967,291. The member does not have all messages cached after 4,294,967,291 (they are missing 4,294,967,292 and 4,294,967,293), so this spin is not useful to the member.

At time 10, the sequence number has rolled over and the member receives a Spin Image Available message with sequence number 2. This is useful since it would be a spin of all orders up to and including rolled over sequence 2, and the member has all messages starting at 4,294,967,294 cached.

At time 11, the member sends a Spin Request message for all messages up to and including 2 and continues to cache Multicast PITCH messages received.

At time 14, the spin server acknowledges the spin request and indicates that three open orders will be sent.

At time 24, the spin server indicates that it has finished sending all open orders. The member must then apply the cached messages from sequence number 3 through current.