Analytical model of IoT CoAP traffic

CoAP and Its Performance Evaluation

“…The synchronous-asynchronous transmission mechanisms have been described by CoAP as piggybacked and separate response [4]. In most cases, the response is carried directly within the acknowledgement message (the request message type must be confirmable).…”

“…This is called Piggybacked Response. A piggybacked response is a response carried directly in the acknowledgment message [4]. The separate response consists of two CoAP messages.…”

“…The first is an ACK message that is sent to prevent the client from deciding that the message has not been transmitted and sending it repeatedly. The second is a Confirmable (CON) message containing the response to the client [4]. Figure 5 shows responses to an optional piggybacked (a) and separate response (b).…”

“…There are many communication and messaging protocols such as CoAP, MQTT, DDS, AMQP in the literature developed for IoT based applications. Many of these IoT protocols, IoT 1 Sakarya University, Turkey ORCID: 0000-0002-9574-9899 2 Sakarya University, Turkey ORCID: 0000-0003-1058-7100 * Corresponding Author unalc@sakarya.edu.tr 3 Sakarya University, Turkey ORCID: 0000-0002-5794-6919 4 Kocaeli University, Turkey, ORCID: 0000-0002-2621-634X devices cosider limited features such as memory, battery, processing capacity, low bandwidth connections [1][2].Constrained Application Protocol (CoAP) is a web transfer protocol based on Representational State Transfer (REST), which uses http functions including GET, PUT, POST, and DELETE methods. Unlike REST, CoAP uses UDP as the communication layer.…”

“…CoAP supports the client/server model that uses request /response communication. CoAP provides two modes of operation: nonconfirmable and confirmable [3][4][5].…”