Page 315 - From Smart Grid to Internet of Energy

280 From smart grid to internet of energy

message-centric protocols are same with the broker-based classifications that
are AMQP, MQTT, JMS and additionally REST included. On the other hand,
the data-centric protocols are similar to bus-based classification where CoAP is
included to DDS and XMPP that focus on successful data delivery. The CoAP is
a web-based, and XMPP and AMQP are application-based protocols. The pro-
tocols and their functions required for IoT-based smart grid applications are pre-
sented as follows.
Constrained Applications Protocol (CoAP): CoAP is a web-based client and
server model protocol that is based on REST architecture on HTTP and operates
in the application layer (APP). The web transfer protocol based on REST rep-
resents a simpler way to exchange data between clients and servers over HTTP.
The constrained devices such as sensors or sensor nodes are utilized as servers
for IoT applications. Although many web-based applications inherit the conges-
tion control by TCP, CoAp does not interact with TCP and operates regarding to
UDP protocol and performs the congestion control by itself. The UDP is easier
to be implemented by using microcontrollers, but it does not support security
tools such as Secure Sockets Layer (SSL) and TLS.
Advanced Message Queuing Protocol (AMQP): AMQP is also an APP pro-
tocol as CoAP that is based on message-centric architecture. Despite of CoAP,
AMQP uses TCP and it ensures the successful message delivery owing to its
authentication and encryption methods based on SSL/TLS controls.
Message Queue Telemetry Transport (MQTT): MQTT is a broker-based
open source protocol managing the message transmission from clients to a cen-
tral broker. It uses TCP protocol and operates a routing mechanism for M2M
connection. It connects up to a thousand of device nodes with enough perfor-
mance and low power consumption.
Java Message Service API (JMS): JMS is a middleware API similar to open
source Java Call Control (JCC) that is responsible of managing message trans-
mission and control. JMS is a web-based API operating on TCP/IP protocol to
provide secure, reliable and asynchronous communication. It separates the APP
and transport layer objectives and supports the communication between differ-
ent applications.
Data Distribution Service (DDS): The DDS is a recent publish/subscribe
protocol used in M2M communication to enable real-time, high performance
and interoperable data transmission. Object Management Group (OMG) has
implemented it. DDS is featured on QoS policies such as urgency, priority,
security, and reliability etc. DDS can inherit the location, redundancy, time,
message flow, and operating platform of the system. The protocol includes
Data-Centric Publish and Subscribe (DCPS) model, and a DDS Interoperability
Wire Protocol (DDSI) that DCPS identifies the DDS architecture, and DDSI
defines interoperability structure.
Representational State Transfer (REST): REST provides a simple way for
clients and subscribers to communicate over HTTP protocol. It is a point-to-
point protocol and operates on TCP/IP. REST enables HTTP methods such