The Advanced Message Queuing Protocol (AMQP) is an
open standard application layer protocol for
message-oriented middleware
Message-oriented middleware (MOM) is software or hardware infrastructure supporting sending and receiving messages between distributed systems. MOM allows application modules to be distributed over heterogeneous platforms and reduces the comple ...
. The defining features of AMQP are message orientation, queuing,
routing (including
point-to-point and
publish-and-subscribe), reliability and security.
[
]
AMQP mandates the behavior of the messaging provider and client to the extent that implementations from different vendors are
interoperable
Interoperability is a characteristic of a product or system to work with other products or systems. While the term was initially defined for information technology or systems engineering services to allow for information exchange, a broader def ...
, in the same way as
SMTP
The Simple Mail Transfer Protocol (SMTP) is an Internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents use SMTP to send and receive mail messages. User-level email clients ty ...
,
HTTP
The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide We ...
,
FTP
The File Transfer Protocol (FTP) is a standard communication protocol used for the transfer of computer files from a server to a client on a computer network. FTP is built on a client–server model architecture using separate control and data ...
, etc. have created interoperable systems. Previous standardizations of
middleware
Middleware is a type of computer software that provides services to software applications beyond those available from the operating system. It can be described as "software glue".
Middleware makes it easier for software developers to implement c ...
have happened at the API level (e.g.
JMS) and were focused on standardizing programmer interaction with different middleware implementations, rather than on providing interoperability between multiple implementations. Unlike JMS, which defines an API and a set of behaviors that a messaging implementation must provide, AMQP is a
wire-level protocol. A wire-level protocol is a description of the format of the data that is sent across the network as a
stream of
byte
The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable uni ...
s. Consequently, any tool that can create and interpret messages that conform to this data format can interoperate with any other compliant tool irrespective of implementation language.
Overview
AMQP is a
binary
Binary may refer to:
Science and technology Mathematics
* Binary number, a representation of numbers using only two digits (0 and 1)
* Binary function, a function that takes two arguments
* Binary operation, a mathematical operation that ta ...
, application layer protocol, designed to efficiently support a wide variety of messaging applications and communication patterns. It provides flow controlled, message-oriented communication with message-delivery guarantees such as ''at-most-once'' (where each message is delivered once or never), ''at-least-once'' (where each message is certain to be delivered, but may do so multiple times) and ''exactly-once'' (where the message will always certainly arrive and do so only once), and authentication and/or encryption based on
SASL and/or
TLS. It assumes an underlying reliable transport layer protocol such as
Transmission Control Protocol
The Transmission Control Protocol (TCP) is one of the main protocols of the Internet protocol suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, the entire suite is common ...
(TCP).
The AMQP specification is defined in several layers: (i) a type system, (ii) a symmetric, asynchronous protocol for the transfer of messages from one process to another, (iii) a standard, extensible message format and (iv) a set of standardised but extensible 'messaging capabilities.'
History
AMQP was originated in 2003 by John O'Hara at
JPMorgan Chase
JPMorgan Chase & Co. is an American multinational investment bank and financial services holding company headquartered in New York City and incorporated in Delaware. As of 2022, JPMorgan Chase is the largest bank in the United States, the ...
in
London
London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...
.
AMQP was conceived as a co-operative open effort. The initial design was by JPMorgan Chase from mid-2004 to mid-2006 and it contracted
iMatix Corporation to develop a C broker and protocol documentation. In 2005 JPMorgan Chase approached other firms to form a working group that included
Cisco Systems
Cisco Systems, Inc., commonly known as Cisco, is an American-based multinational digital communications technology conglomerate corporation headquartered in San Jose, California. Cisco develops, manufactures, and sells networking hardware, ...
,
IONA Technologies, iMatix,
Red Hat, and
Transaction Workflow Innovation Standards Team {{third-party, date=April 2015
Transaction Workflow Innovation Standards Team (Twist) is a not-for-profit industry standards group. It does not charge anything for involvement. The main goal of Twist is to create non-proprietary XML message stan ...
(TWIST). In the same year JPMorgan Chase partnered with Red Hat to create
Apache Qpid, initially in Java and soon after C++. Independently,
RabbitMQ
RabbitMQ is an open-source message-broker software (sometimes called message-oriented middleware) that originally implemented the Advanced Message Queuing Protocol (AMQP) and has since been extended with a plug-in architecture to support Str ...
was developed in
Erlang by Rabbit Technologies, followed later by the
Microsoft
Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washin ...
and StormMQ implementations.
The working group grew to 23 companies including
Bank of America
The Bank of America Corporation (often abbreviated BofA or BoA) is an American multinational investment bank and financial services holding company headquartered at the Bank of America Corporate Center in Charlotte, North Carolina. The bank ...
,
Barclays, Cisco Systems,
Credit Suisse,
Deutsche Börse
Deutsche Börse AG () or the Deutsche Börse Group, is a German company offering marketplace organizing for the trading of shares and other securities. It is also a transaction services provider. It gives companies and investors access to gl ...
,
Goldman Sachs,
HCL Technologies Ltd,
Progress Software
Progress Software Corporation (Progress) is an American public company that offers software for creating and deploying business applications. Headquartered in Burlington, Massachusetts with offices in 16 countries, the company posted revenues ...
,
IIT Software
The Indian Institutes of Technology (IITs) are central government owned public technical institutes located across India. They are under the ownership of the Ministry of Education of the Government of India. They are governed by the Ins ...
,
INETCO Systems Limited,
Informatica
Informatica is an American software development company founded in 1993. It is headquartered in Redwood City, California. Its core products include Enterprise Cloud Data Management and Data Integration. It was co-founded by Gaurav Dhillon and Di ...
(including 29 West), JPMorgan Chase,
Microsoft Corporation, my-Channels,
Novell,
Red Hat,
Software AG
Founded in 1969, Software AG is an enterprise software company with over 10,000 enterprise customers in over 70 countries. The company is the second largest software vendor in Germany, and the seventh largest in Europe. Software AG is traded on t ...
,
Solace Systems, StormMQ,
Tervela Inc., TWIST Process Innovations ltd,
VMware
VMware, Inc. is an American cloud computing and virtualization technology company with headquarters in Palo Alto, California. VMware was the first commercially successful company to virtualize the x86 architecture.
VMware's desktop software ru ...
(which acquired Rabbit Technologies) and
WSO2
WSO2 is an open-source technology provider founded in 2005. It offers an enterprise platform for integrating application programming interfaces (APIs), applications, and web services locally and across the Internet.
History
WSO2 was founded b ...
.
In August 2011, the AMQP working group announced its reorganization into an
OASIS member section.
AMQP 1.0 was released by the AMQP working group on 30 October 2011, at a conference in New York. At the event Microsoft, Red Hat,
VMware
VMware, Inc. is an American cloud computing and virtualization technology company with headquarters in Palo Alto, California. VMware was the first commercially successful company to virtualize the x86 architecture.
VMware's desktop software ru ...
, Apache, INETCO and IIT Software demonstrated software running the protocol in an interoperability demonstration. The next day, on 1 November 2011, the formation of an
OASIS Technical Committee was announced to advance this contributed AMQP version 1.0 through the international open standards process. The first draft from OASIS was released in February 2012, the changes as compared to that published by the Working Group being restricted to edits for improved clarity (no functional changes). The second draft was released for public review on 20 June (again with no functional changes), and AMQP was approved as an OASIS standard on 31 October 2012.
OASIS AMQP was approved for release as an ISO and IEC International Standard in April 2014. AMQP 1.0 was balloted through the Joint Technical Committee on Information Technology (JTC1) of the International Standards Organization (ISO) and the International Electrotechnical Commission (IEC). The approved OASIS AMQP submission has been given the designation, ISO/IEC 19464.
Previous versions of AMQP were 0-8, published in June 2006, 0-9, published in December 2006, 0-10 published in February 2008 and 0-9-1, published in November 2008. These earlier releases are significantly different from the 1.0 specification.
Whilst AMQP originated in the financial services industry, it has general applicability to a broad range of
middleware
Middleware is a type of computer software that provides services to software applications beyond those available from the operating system. It can be described as "software glue".
Middleware makes it easier for software developers to implement c ...
problems.
Description of AMQP 1.0
Type system
AMQP defines a
self-describing
In computer programming, self-documenting (or self-describing) source code and user interfaces follow naming conventions and structured programming conventions that enable use of the system without prior specific knowledge. In web development, ...
encoding scheme allowing interoperable representation of a wide range of commonly used types. It also allows typed data to be
annotated
An annotation is extra information associated with a particular point in a document or other piece of information. It can be a note that includes a comment or explanation. Annotations are sometimes presented in the margin of book pages. For ann ...
with additional meaning, for example a particular string value might be annotated so that it could be understood as a
URL. Likewise a map value containing key-value pairs for 'name', 'address' etc., might be annotated as being a representation of a 'customer' type.
The type-system is used to define a message format allowing standard and extended meta-data to be expressed and understood by processing entities. It is also used to define the communication primitives through which messages are exchanged between such entities, i.e. the AMQP ''frame bodies''.
Performatives and the link protocol
The basic unit of data in AMQP is a ''frame''. There are nine AMQP frame bodies defined that are used to initiate, control and tear down the transfer of messages between two peers. These are:
* open (the ''connection'')
* begin (the ''session'')
* attach (the ''link'')
* transfer
* flow
* disposition
* detach (the ''link'')
* end (the ''session'')
* close (the ''connection'')
The ''link protocol'' is at the heart of AMQP.
An ''attach'' frame body is sent to initiate a new link; a ''detach'' to tear down a link. Links may be established in order to receive or send messages.
Messages are sent over an established ''link'' using the ''transfer'' frame. Messages on a link flow in only one direction.
Transfers are subject to a credit based flow control scheme, managed using ''flow'' frames. This allows a process to protect itself from being overwhelmed by too large a volume of messages or more
simply to allow a subscribing link to pull messages as and when desired.
Each transferred message must eventually be ''settled''. Settlement ensures that the sender and receiver agree on the state of the transfer, providing reliability guarantees. Changes in state and settlement for a transfer (or set of transfers) are communicated between the peers using the ''disposition'' frame. Various reliability guarantees can be enforced this way: at-most-once, at-least-once and exactly-once.
Multiple links, in both directions, can be grouped together in a ''session''. A session is a bidirectional, sequential conversation between two peers that is initiated with a ''begin'' frame and
terminated with an ''end'' frame. A connection between two peers can have multiple sessions multiplexed over it, each logically independent. Connections are initiated with an ''open'' frame in which
the sending peer's capabilities are expressed, and terminated with a ''close'' frame.
Message format
AMQP defines as the ''bare message'', that part of the message that is created by the sending application. This is considered immutable as the message is transferred between one or more processes.
Ensuring the message as sent by the application is immutable allows for end-to-end message signing and/or
encryption
In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can de ...
and ensures that any integrity checks (e.g. hashes or
digests
Digest may refer to:
Biology
*Digestion of food
*Restriction digest
Literature and publications
*'' The Digest'', formerly the English and Empire Digest
*Digest size magazine format
* ''Digest'' (Roman law), also known as ''Pandects'', a digest ...
) remain valid. The message can be annotated by intermediaries during transit, but any such annotations are kept distinct from the immutable ''bare message''. Annotations may be added before or after the bare message.
The ''header'' is a standard set of delivery-related annotations that can be requested or indicated for a message and includes time to live, durability, priority.
The bare message itself is structured as an optional list of standard properties (message id, user id, creation time, reply to, subject, correlation id, group id etc.), an optional list of
application-specific properties (i.e., extended properties) and a body, which AMQP refers to as application data.
Properties are specified in the AMQP type system, as are annotations. The application data can be of any form, and in any encoding the application chooses. One option is to use the AMQP type system to send structured, self-describing data.
Messaging capabilities
The link protocol transfers messages between two ''nodes'' but assumes very little as to what those nodes are or how they are implemented.
A key category is those nodes used as a ''rendezvous point'' between senders and receivers of messages (e.g. ''queues'' or ''topics''). The AMQP specification calls such nodes ''distribution nodes'' and codifies some common behaviors.
This includes:
* some standard outcomes for transfers, through which receivers of messages can for example accept or reject messages
* a mechanism for indicating or requesting one of the two basic distribution patterns, competing- and non-competing- consumers, through the ''distribution modes'' ''move'' and ''copy'' respectively
* the ability to create nodes on-demand, e.g. for temporary response queues
* the ability to refine the set of message of interest to a receiver through filters
Though AMQP can be used in simple peer-to-peer systems, defining this framework for messaging capabilities additionally enables interoperability with messaging intermediaries (brokers, bridges etc.)
in larger, richer messaging networks. The framework specified covers basic behaviors but allows for extensions to evolve that can be further codified and standardised.
Implementations
AMQP 1.0 broker implementations
*
Apache Qpid, an
open-source project at the
Apache Foundation
The Apache Software Foundation (ASF) is an American nonprofit corporation (classified as a 501(c)(3) organization in the United States) to support a number of open source software projects. The ASF was formed from a group of developers of the ...
*
Apache ActiveMQ, an
open-source project at the
Apache Foundation
The Apache Software Foundation (ASF) is an American nonprofit corporation (classified as a 501(c)(3) organization in the United States) to support a number of open source software projects. The ASF was formed from a group of developers of the ...
*
Azure Event Hubs
*
Azure Service Bus
*
Solace
Consolation, consolement, and solace are terms referring to psychological comfort given to someone who has suffered severe, upsetting loss, such as the death of a loved one. It is typically provided by expressing shared regret for that loss and ...
PubSub+, a multi-protocol broker in hardware, software, and cloud
Pre-1.0 AMQP broker implementations
*
JORAM, a Java
open-source implementation from the
OW2 Consortium
OW2 is an independent non-profit international consortium dedicated to developing open-source software code infrastructure for middleware information systems. OW2 federates IT vendors and users, universities, and research centers from Europe, ...
.
*
Apache Qpid maintains support for multiple AMQP versions
* StormMQ, a hosted
message queuing service
A message queueing service is a message-oriented middleware or MOM deployed in a compute cloud using software as a service model. Service subscribers access queues and or topics to exchange data using point-to-point or publish and subscribe pat ...
using AMQP. It is offered as a commercial
managed service.
*
RabbitMQ
RabbitMQ is an open-source message-broker software (sometimes called message-oriented middleware) that originally implemented the Advanced Message Queuing Protocol (AMQP) and has since been extended with a plug-in architecture to support Str ...
, an
open-source project sponsored by
VMware
VMware, Inc. is an American cloud computing and virtualization technology company with headquarters in Palo Alto, California. VMware was the first commercially successful company to virtualize the x86 architecture.
VMware's desktop software ru ...
, primarily supports AMQP 0-9-1, with 1.0 via a plugin
Specification
AMQP protocol version 1.0 is the current specification version. It focuses on core features which are necessary for interoperability at Internet scale. It contains less explicit routing than previous versions because core functionality is the first to be rigorously standardized. AMQP 1.0 interoperability has been more extensively tested with more implementors than prior versions.
The AMQP website contains th
OASIS specification for version 1.0
Earlier versions of AMQP, published prior to the release of 1.0 (see History above) and significantly different from it, include:
AMQP 0-9-1 which has clients available "for many popular programming languages and platforms"
AMQP 0-10
Comparable specifications
These are the known open protocol specifications that cover the same or similar space as AMQP:
*
Streaming Text Oriented Messaging Protocol (STOMP), a text-based protocol developed at Codehaus; uses the JMS-like semantics of 'destination'.
*
Extensible Messaging and Presence Protocol
Extensible Messaging and Presence Protocol (XMPP, originally named Jabber) is an open communication protocol designed for instant messaging (IM), presence information, and contact list maintenance. Based on XML (Extensible Markup Language), it ...
(XMPP), the Extensible Messaging and Presence Protocol.
*
MQTT
MQTT (originally an initialism of MQ Telemetry Transport) is a lightweight, publish-subscribe, machine to machine network protocol for Message queue/Message queuing service. It is designed for connections with remote locations that have devices ...
, a lightweight publish-subscribe protocol.
*
OpenWire as used by
ActiveMQ.
Java Message Service
The Jakarta Messaging API (formerly Java Message Service or JMS API) is a Java application programming interface (API) for message-oriented middleware. It provides generic messaging models, able to handle the producer–consumer problem, that can ...
(JMS), is often compared to AMQP. However, JMS is an API specification (part of the
Java EE
Jakarta EE, formerly Java Platform, Enterprise Edition (Java EE) and Java 2 Platform, Enterprise Edition (J2EE), is a set of specifications, extending Java SE with specifications for enterprise features such as distributed computing and web ser ...
specification) that defines how message producers and consumers are implemented. JMS does not guarantee interoperability between implementations, and the JMS-compliant
messaging system
In computer science, inter-process communication or interprocess communication (IPC) refers specifically to the mechanisms an operating system provides to allow the processes to manage shared data. Typically, applications can use IPC, categori ...
in use may need to be deployed on both client and server. On the other hand, AMQP is a wire-level protocol specification. In theory AMQP provides interoperability as different AMQP-compliant software can be deployed on the client and server sides. Note that, like
HTTP
The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide We ...
and
XMPP
Extensible Messaging and Presence Protocol (XMPP, originally named Jabber) is an open communication protocol designed for instant messaging (IM), presence information, and contact list maintenance. Based on XML (Extensible Markup Language), i ...
, AMQP does not have a standard API.
See also
*
Peer-to-peer
Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the network. They are said to form a peer-to-peer ...
*
Message queue
In computer science, message queues and mailboxes are software-engineering components typically used for inter-process communication (IPC), or for inter- thread communication within the same process. They use a queue for messaging – the ...
*
Message queuing service
A message queueing service is a message-oriented middleware or MOM deployed in a compute cloud using software as a service model. Service subscribers access queues and or topics to exchange data using point-to-point or publish and subscribe pat ...
*
Data Distribution Service
The Data Distribution Service (DDS) for real-time systems is an Object Management Group (OMG) machine-to-machine (sometimes called middleware or connectivity framework) standard that aims to enable dependable, high-performance, interoperable, re ...
*
IBM MQ
IBM MQ is a family of message-oriented middleware products that IBM launched in December 1993. It was originally called MQSeries, and was renamed ''WebSphere MQ'' in 2002 to join the suite of IBM WebSphere, WebSphere products. In April 2014, it was ...
References
External links
*
OASIS AMQP technical committee*
ttp://www.omg.org/news/meetings/workshops/RT-2007/04-3_Pardo-Castellote-revised.pdf OMG Analysis of AMQP and comparison with DDS-RTPSGoogle Tech Talk, with video and slides, about RabbitMQPresentation of AMQP and RestMS messaging at FOSDEM 2009
{{OASIS Standards
Application layer protocols
Inter-process communication
Message-oriented middleware
Middleware
Network protocols
Open standards