Overview of Web Protocols

CoAP – Constrained Application Protocol

CoAP is a specialized web transfer protocol for use with constrained nodes and constrained (e.g., low-power, lossy) networks.

• Ideal when

– Constrained nodes (e.g., 8-bit microcontrollers with limited RAM and ROM) such as wireless sensor networks (WSNs) requiring very low overhead

• Key Features

• –  Web protocol fulfilling M2M requirements in constrained environments

• –  UDP [RFC0768] binding with optional reliability supporting unicast and multicast requests.

• –  Asynchronous message exchanges

• –  Low header overhead and parsing complexity

• –  Uniform resource identifier (URI) and content-type support

• –  Simple proxy and caching capabilities

• –  Security binding to Datagram Transport Layer Security (DTLS) 

  CoAP Benefits

  • Open IETF standard

  • Low overhead and an excellent choice in constraints applications

  • Works well in noisy & lossy environments

  • Built-in discovery

  • Strong DTLS security

  • Asynchronous subscription 

    XMPP – Extensible Messaging and Presence Protocol

    XMPP is an open instant messaging protocol usually implemented via a client- server architecture wherein a client utilizing XMPP accesses a server over a TCP connection, and servers also communicate with each other over TCP connections

    • Ideal when

    – Connecting devices to people. For example, connecting home thermostat to a web server so data can be accessed over a phone
  • • Key Features

    • –  End to end communication between any peer. With name@domain.com addressing scheme, it enables connections between distant, mostly unrelated end points

    • –  Transport with end nodes can be of any type (IP, ZigBee, Bluetooth...)

    • –  XML based - easily extensible with arbitrary payloads. Distributed network of “web services”

    • –  Security: Very robust with Encryption, client authentication, & client authorization mandatory

    • –  Near real-time communication 

      XMPP Extension Protocols (XEP) for IoT

      Provides the underlying architecture, basic operations and data structures for sensor data communication over XMPP networks 

      XMPP Benefits

      • Real time messaging at massive scale – 100,000+ nodes

      • Secure – XMPP server may be isolated from the public network and robust security using SASL and TSL are built into the core

      • • Open – XMPP protocols are free, open, public and have been widely adopted

      • • Decentralized – the architecture of the XMPP network is similar to email – anyone can run their own XMPP server 

        Data Distribution Service (DDS)

        The first open international middleware standard directly addressing publish-subscribe communications for real-time and embedded

        systems

      • • Ideal for
        

        – Real time, secure communications between devices

        • Key Features

        • –  DDS is decentralized – can be deployed without servers and brokers

        • –  Publish/subscribe architecture

        • –  Scalable performance

          • Millions of data elements

          • .5m updates/sec

          • 10us latency

          • 1000s consumers/update

        • –  Managed with QoS

        • –  Reliable - no single point of failure

        • –  Built in detecting presence of applications 

          DDS Protocol Benefits

          • Platform neutral: Operating systems and Programming Languages

          • Delivers flexibility, reliability and performance necessary for complex, real- time applications

          • Real-time Quality of Service (QoS) control

          • Decentralized architecture allows for frequent observation of changes & uses network resources efficiently

          • Dynamic discovery of publishers and subscribers 

            AMQP – Advanced Messaging Queuing Protocol

            The Advanced Message Queuing Protocol (AMQP) is an open internet protocol for business messaging. It defines a binary wire-level protocol that allows for the reliable exchange of business messages between two parties

            • Ideal for

            – Connecting various enterprise systems in the enterprise and providing business processes with the information they need

            • Key Features

            • –  Multiple messaging related features - Reliable queuing, topic- based publish and subscribe, flexible routing, etc

            • –  Session and transactional message transfer

            • –  Efficient – packet size 60 bytes

            • –  Security – SSL/TLS, SASL

            • –  Quality of Service – best effort, at least once, exactly once 

              • All AMQP clients interoperate with all AMQP servers

              • Diverse programming languages can communicate easily

              • Legacy message brokers can be retrofitted to remove proprietary protocols

              • Enables messaging as a cloud service 

              AMQP Benefits

              • Flexible, open and interoperable. AMQP can connect across organizations and technologies while guaranteeing QoS and security

              – Realize the savings commoditization brings; remove vendor lock-in
            • – Connect applications on different platforms; choose the right platform for the job

              • –  Connect to business partners using a full featured open standard; remove technical barriers to trade

              • –  Reliability operate at a distance, or over poor networks