Heartbeat Messages

The Sequenced Unit Header with a count field set to 0 will be used for Heartbeat messages. During trading hours Heartbeat messages will be sent from all multicast addresses if no data has been delivered within 1 second. Heartbeat messages never increment the sequence number.

Outside of trading hours Cboe sends heartbeat messages on all real-time channels with a sequence of 0 to help users validate multicast connectivity. Heartbeat messages may not be sent from 12:00 a.m. - 1:00 a.m. ET or during maintenance windows.

Cboe expects Heartbeat messages to be sent to the GRP and Spin Servers on live connections no less than every 5 seconds. Failure to receive two consecutive Heartbeat messages will result in the GRP or Spin Server terminating the client connection.