Message Structured
Header – This part is network specific, and shows Institution Identification Codes (IICs) The Institution Identification Code explains why Mastercard and Visa use different message header structure.
| Header | > This part is network specific, and shows Institution Identification Codes (IICs) that explains why Mastercard and Visa use different message header structure.
Typically shows the size of the message, can contain information about the size of header plus the size of message. An example of a header is 0158 which depicts the content of the message (mti+bitmap+data elements) is 158 bytes | | --- | --- | | Message Type Indicator (MTI) | > MTI in ISO 8583 identifies the message's version, class, function, and origin. It consists of four numeric parts. There are three versions of the standard: 1987, 1993, and 2003. Together, these MTI fields define the type of message being transmitted.
0100 Digit 1 indicates the version of ISO 8583 (version of ISO 8583 (0 = 1987 version)) Digit 2 indicates the class of the message (class of the message (1 = authorization message)) Digit 3 indicates the function of the message (function of the message (1 = response)) Digit 4 indicates who initiated the communication (who began the communication (0 = acquirer)) | | Bitmaps | > The primary bitmap specifies whether fields 1 – 64 are present. If there is also a secondary bitmap in the message, it indicates whether fields 65 – 128 exist. | | Data elements | Message data elements are defined by the ISO 8583 protocol, and each individual data element contains the information for that specific transaction and each has a specified meaning |
