Login Response Message Fields
A Login Response message is sent in response to a Login Request message. On a successful login, the LoginResponseStatus will be set to A. On a failed login, LoginResponseStatus will be set to a value other than A, and LoginResponseText will be set to an appropriate failure description.
Note that the repeating group starting with field UnitNumber provides the highest available Cboe to member sequence number for the specified unit. For unitized ports, only the unit of the port will populate this group (i.e., NumberOfUnits will be 1).
| Field Name | Offset | Length | Data Type | Description |
|---|---|---|---|---|
| StartOfMessage | 0 | 2 | Binary | B0 E3 (58288) |
| MessageLength | 2 | 2 | Binary | (76 + NumberOfUnits*5) |
| MessageType | 4 | 2 | Binary | F5 01 (501) |
| MatchingUnit | 6 | 1 | Binary | Will be zero |
| Reserved | 7 | 1 | Binary | Unspecified |
| SequenceNumber | 8 | 4 | Binary | Will be zero |
| LoginResponseStatus | 12 | 1 | Text |
|
| LoginResponseText | 13 | 60 | Text | Human-readable text with additional information about the reason for rejection. ASCII NUL (0x00) filled on the right, if necessary. |
| ClientSequence | 73 | 4 | Binary | Last inbound (member to Cboe) message sequence number processed by Cboe on this port. |
| NumberOfUnits | 77 | 1 | Binary | A number, n, of unit/sequence pairs to follow, one per unit. A pair for every unit will be sent, even if no messages have been sent to this port today. For logins having LoginResponseStatus other than A, Q, or R, this will be 0. |
| →UnitNumber | 78 | 1 | Binary | A unit number |
| →UnitSequence | 79 | 4 | Binary | Highest available Cboe to member sequence number for the unit. |





