Device Control Protocol Specification (DCP)
an Internet Protocol for Controlling Devices

CONTENTS

Up
Introduction
Conventions
Parameters
Fundamentals
Message Format
Requests
Responses
Entities
Request Methods
Reserved Objects
Status Codes
Headers
Session Management
Authentication
Security
XML DTD

 

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DCP MESSAGE

DCP messages are the basic building blocks of DCP communication.  DCP messages build the transactions which make up DCP sessions.  In DCP, there are different types of messages and they are made up of request lines, status (or response) lines, headers and bodies.


MESSAGE TYPES

The DCP messages consist of requests from initiators to targets and responses from targets to initiators.

Syntax

MESSAGE HEADERS

DCP message headers are attribute and value pairs embedded within messages that are used to convey information about the message, initiators, targets and desired behavior.  DCP header fields follow the same generic format as that given in Section 3.1 of RFC 822. Each header field consists of a name followed immediately by a colon (":"), a single space (sp) character, and the field value. Field names are case-insensitive. Header fields can be extended over multiple lines by preceding each extra line with at least one sp or ht, though this is not recommended.

Syntax

The order in which header fields are received is not significant. However, it is "good practice" to send general header fields first, followed by DCP headers (request and response headers) and entity header fields.

Multiple DCP header fields with the same fieldName may be present in a message if and only if the entire fieldValue for that header field is defined as a comma separated list.  It must be possible to combine the multiple header fields into one "fieldName: fieldValue pair, without changing the semantics of the message, by appending each subsequent fieldValue to the first, each separated by a comma.


GENERAL HEADER FIELDS

There are a few header fields which have general applicability for both request and response messages, but which do not apply to the entity being transferred. These header fields apply only to the message being transmitted and they are referred to as general headers.

Syntax

 

 

© 2000 Chris Armbruster