Cboe One Server (TCP)

The user connects to an assigned host and port using a TCP/IP socket.

Upon connection, the user must send a Cboe One Login message. The Cboe One Login message Next Sequence field allows Cboe One users to specify the next sequence number they expect to receive. If a Cboe One user logs in after trading begins or after connection loss, the Next Sequence field can be used to tell the server to replay any Trade and Trade Break messages that have occurred since the last received Trade or Trade Break message.

If the Next Sequence field is set to 1 (one), then all Trade and Trade Break messages from the beginning of the day will be replayed after the server sends a successful Login Response message. Once the server has replayed any Trade and Trade Break messages, it will deliver relevant Market Status message information, RPI message information, Trading Status messages, and a spin of Symbol Summary, Opening/Close Price and ADAP messages from its cache for each active symbol. Then the server will send the user a Replay Complete message followed by the live stream of Symbol Summary, Best Quote Update, ADAP, RPI, Trade, Trade Break, Market Status, Trading Status, Opening/Closing Price, and End of Day Summary messages.

If the Next Sequence field is set to 0 (zero), then no Trade or Trade Break messages will be replayed after the server sends a successful Login Response message. However, Cboe One users may still receive a spin of Market Status, RPI, Trading Status, Symbol Summary, Opening/Close Price and ADAP messages followed by a Replay Complete message before receiving the live stream of Symbol Summary, Best Quote Update, ADAP, RPI, Trade, Trade Break, Market Status, Trading Status, Opening/Closing Price , and End of Day Summary messages.

If a Cboe One user’s process cannot keep up with the Cboe One feed’s rate of transmission, the connection will be closed by the server. The user should then reconnect and login with the appropriate Next Sequence number to receive any missed trades, and spin of the latest image for all symbols.