- Gümüşhane Üniversitesi Fen Bilimleri Dergisi
- CMES 2018 Additional Issue
- Grid Ağ Topolojilerinde CoAP ve CoCoA Tıkanıklık Kontrol Mekanizmalarının Karşılaştırılması...
Grid Ağ Topolojilerinde CoAP ve CoCoA Tıkanıklık Kontrol Mekanizmalarının Karşılaştırılması
Authors : Alper Kamil Demir, Fatih Abut
Pages : 53-60
Doi:10.17714/gumusfenbil.436056
View : 11 | Download : 4
Publication Date : 2018-11-30
Article Type : Research
Abstract :The Internet of Things (IoT) is a vision of the future Internet. Due to limited resources of IoT devices, a new generation of protocols and algorithms are being developed and standardized. The Constrained Application Protocol (CoAP) has been designed by the Internet Engineering Task Force (IETF) for application layer communication. CoAP is based on User Datagram Protocol (UDP), a simple transport layer protocol that does not handle congestion within the network. However, the phenomenon of congestion in IoT networks is also a major problem. Thus, the core CoAP specification offers a basic CoAP congestion control (CC) mechanism based on retransmission timeout (RTO) with binary exponential backoff (BEB). Default CoAP CC is insensitive to network conditions. Thus, to improve the default CoAP CC, CoAP Simple Congestion Control/Advanced (CoCoA), defined in a draft specification, is being standardized by the IETF CoRE working group. Nevertheless, comparison of default CoAP CC and CoCoA has not been sufficiently investigated in the literature. In this paper, we investigate and present comparison of default CoAP CC and CoCoA in terms of throughput (i.e. number of requests/second) by varying number of concurrent clients where each client continuously sends back-to-back traffic to servers residing in 1x6, 3x6 and 5x6 grid network topology. Our results show that CoCoA is not always better than default CoAP CC in terms of throughput in some scenarios. As a result, design and development of new CoAP CC mechanisms are open to research.Keywords : Internet of Things, Congestion control, CoAP, CoCoA, Cooja, ContikiOS