The Heartbeat (tag 35-MsgType=0) message is sent in response to a iLink 2 Test Request to ensure connectivity.

TagNameFIX TypeEnumerationReqDescription

iLink 2 Standard Header - Client System to CME Globex

iLink 2 Standard Header - CME Globex to Client System

35MsgTypeString(2)0=HeartbeatYHeader tag identifying message type.





Required if heartbeat message is generated in response to a Test Request message. In this case, this tag must contain the TestReqID that was sent in the Test Request message.


0 – Split message 

1 – Out-of-order message 

2 – Complete message 


Indicates whether a message was subject to additional processing as a result of being:

  • split among multiple packets (0)
  • out-of-order (1)
  • a previously submitted split message (2)

If absent, then the message was not subject to additional processing.

iLink 2 Standard Message Trailer

End of message.

Y: Required by FIX protocol, Y*: Required by CME Globex (not by FIX protocol), N: Not Required, C: Conditionally