Transfer message in HTTP protocol: XML(UDDI,WSDL,SOAP);WS-Security;XML-RPC;JSON;REST
Business process protocol: BPEL, BPMN
Message protocol: SOAP, AMQP, MQTT, STOMP
Java: JMS
Socket: WebSocket
Broker object protocol: COM/DCOM, CORBA/IIOP(HTIOP,SSLIOP), JAVA RMI
Socket: WebSocket
Adobe message protocol: AMF
P2P: WebRTC
If you look at the first list of protocols and consider the http protocol as a service working with XML, from this point of view, these protocols have the greatest affinity.
Yes, all of these protocols can be wrapped into other protocols, such as FTP, or even use UDP datagrams.
Especially when you consider the level of IP protocols - TCP/IP, UDP/IP.
But, among other things HTML, SOAP, UDDI and other protocols of the first list are 7 layers of the network model OSI (application). And, this list is wrapped or transmitted using HTML. Either as parameters or as a file server in HTTP.
Other lists have a different affinity, but have a common feature - the interaction between the server-server and the client-server part.
For example there is no authority for AJAX.
Yes, you can make custom realization browser on the server and then, you will have an emulation system interaction between AJAX-AJAX web applications on the server, but for me - it is far-fetched.
All 7 levels include their titles, and each represents the next, as a package.
The thing is that the higher level models OSI, the easier access to the interior nesting doll man.
Most will be able to work with the information in the upper levels. It seems to me more important to the final information.
Electromagnetic oscillations can also enjoy - such as the northern lights.
Or transformator Tesla.
But it is an aesthetic pleasure.
A task-level protocols 7 - practical and pragmatic.
It seems to me, that the message is the OSI model, which can derive from the possibility of interaction at the Web systems.
Yes, you can go down to the bottom and say - put in an electrical capacitor circuit and thus tear flow of electric current - do galvanic isolation.
But oscillatory processes go further - through the condenser, and consider this process as a signaling or information, and the process will assume the message.
Thus you need to decide - what is the message? What is the transmission medium? And the macroscopic level of abstraction at which you decide to consider the phenomenon.