Microtronix Access Serial-TCP/IP Converter
5 Encapsulation Message Formats
The following are the formats of the messages used to encapsulate frame data over TCP connections.
The TCP/IP host is expected to implement one of these methods if message preservation is required.
Count (length) fields are in network byte order (big endian) with most significant byte first, least
significant byte last.
5.1 MBIT (2byte count field)
Simple encapsulation of data using a 2-byte length field. Used to encapsulate and demarcate frame
data. Each MBIT message contains the data from an individual frame. The purpose is to preserve the
boundaries of application messages.
Count = x
Payload (x bytes)
Error detection is not performed on the header, and any error will cause data loss and/or stalling.
5.2 RFC1006 (ISO TP)
Encapsulation method to provide ISO Transport Service for bridging between X.25 and TCP hosts.
Preserves application message boundaries similar to MBIT above, and can be used as an alternative to
MBIT. The header is 4 bytes.
03
00
Count = 4+x
Payload (x bytes)
Error detection is performed on the header, and any errors will cause the connection to be terminated.
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