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The Establishment Acknowledgment message is sent when an Establish message from a customer is accepted by CME.


TagNameBinary TypeBinary LengthReqEnumerationDescription

Matches Establish.UUID.

Matches Establish.RequestTimestamp.

Next expected message sequence number.

On primary connection, the expected message sequence number of the next business message from CME to customer.

  • At the beginning of the week this should be set to 1
  • Should be set to last known message sequence number + 1 for Establish message sent midweek using same UUID as previous Establish message
  • Should be set to 1 for Establish message sent midweek using different UUID from previous Establish message

On backup connection, this will be set to 0.


Reflects the sequence number of the last business message published by CME with the PreviousUUID.

If no business message was published, this will be zero.


Refers to the UUID sent in the previous message before this message from CME.

  • This can be the CME assigned default UUID=0 for messages published by CME before first Negotiation of customer at the beginning of the week
  • This can be the last UUID as used by the customer from the previously Established session
  • If no business message has been published by CME, this will also be set to 0

The longest time in milliseconds that CME will wait before sending a keep alive Sequence message.

CME Globex will echo back the keep-alive interval submitted in the customer Establish message.

Indicates the expiration date of the HMAC secret key.  Sent in number of days since Unix epoch.

0 – Backup

1 – Primary

Indicates whether the connection is the primary or backup.


0=Split Msg Delayed

1=Out of Order Msg Delayed

2=Complete Msg Delayed

Indicates if a message was delayed as a result of:

  • being split among multiple packets (0)
  • TCP re-transmission (1)
  • due to a previously submitted split or out of order message (2).

If absent then the message was not delayed, split, or received out of order.