Recommended Login
"Request replay of everything that you missed"
The login protocol supports a variety of options for how a participant may want to approach reconciling sequence numbers and messages after a disconnection. For most participants, the following Login strategy is the simplest approach to support a robust, lossless login experience:
| Field Name | Value | Comment |
|---|---|---|
| StartOfMessage | BO E3 | |
| MessageLength | 1E 00 | 30 |
| MessageType | 01 00 | 1 (login request) |
| MatchingUnit | 00 | |
| Reserved | 00 | |
| SequenceNumber | 00 | |
| SessionId | 41 42 43 44 | (ex. "ABCD") - Session Id as supplied by Cboe |
| SessionSubId | 30 30 30 31 | ex. "0001") Session Sub Id as supplied by Cboe |
| Password | 61 62 63 64 65 66 67 68 69 6A | (ex. "abcdefghij") Password |
| ReplayInstruction | 52 | "R" - Replay unknown units. |
| NumberOfUnits | 02 | There are 2 rows in the array below, representing the 2 system matching units. |
| →UnitNumber | 01 | Matching unit #1 |
| →UnitSequence | 00 00 00 00 | Last SequenceNumber that participant received with MatchUnit=1. Zero if participant has not received anything for MatchUnit=1, for instance as the first login of the day. |
| →UnitNumber | 02 | Matching unit #2 |
| →UnitSequence | 00 00 00 00 | Last SequenceNumber that participant received with MatchUnit=2. Zero if participant has not received anything for MatchUnit=2, for instance as the first login of the day. |