Sequence Reset

A reset sequence operation is not available for Binary Order Entry. However, a Member can send a Login Request message with NoUnspecifiedUnitReplay field enabled, and NumberOfUnits field set to zero. Then, upon receiving a Login Response message from Cboe, the Member can use the LastReceivedSequenceNumber field as the sequence starting point for sending future messages.

Cboe Titanium U.S. Options BOE Specification - Sequence Reset | Cboe