Overview

The rad protocol is a bidirectional binary protocol that operates over a single stream. Communication in both directions takes the form of discrete messages. These messages are framed using RPC record marking. For more information, see the “RECORD MARKING STANDARD” section in the RPC standard.

The individual messages take the formats documented in this appendix. Even though RPC record marking permits skipping messages of unknown format, both the client and the server are free to immediately drop the connection when an invalid message is seen.

The rad protocol is built using XDR, so for simplicity and clarity, the XDR primitive type names and syntax are used throughout this appendix. For example:

• “FOO<>” — represents a variable-length array of FOOs, communicated as an unsigned int containing the size followed by that number of FOOs.

• “FOO[n]” — represents a fixed-length array of a predetermined size, communicated only as the nFOOs.

• “FOO *” — represents an optional value communicated as a boolean value followed by a FOO if and only if the boolean value is true.