Usually announced to the ICT community as rivals in the Internet-of-Things (IoT) context, cloud and edge could work together according to their respective capabilities. Today's IoT applications can be dependent neither on a single technology (either SQL or noSQL) nor on a single operation model (either centralized or decentralized). The multiple challenges are complexity of user scenarios, multiplicity of things, sensitivity of data, etc. This paper raises the question of who serves IoT better? Cloud, only; edge, only; or both together. To answer this question, clouds' and edges' duties are identified and then a set of collaborative scenarios are discussed with respect to these duties.
KEYWORDScloud computing, edge computing, Internet-of-Things
MOTIVATIONSThe ICT community is known for marketing new solutions using multiple buzzwords that, usually, trigger debates, sometimes heated, among these solutions' advocates and opponents. Buzzwords include, but not limited to, Everything-as-a-Service (*aaS), edge (sometimes referred to as fog) computing, blockchain, big data, deep learning, and, lately, Internet-of-Things (IoT).IoT is about allowing people to have anywhere and anytime control over their cyber-physical surroundings such as homes, offices, and malls. IoT-compliant things (things for short) could be anything ranging from white goods and wrist watches to RFID tags and moisture sensors. According to Gartner (http://goo.gl/J2TwR6), 6.4 billion connected things were used in 2016, which is 3% increase from 2015, and will reach 20.8 billion by 2020. Smart city (eg, Smart Dubai: http://smartdubai.ae) is one of the highly cited examples that illustrates the potential benefits of IoT to governments and citizens. To what extent could IoT achieve the dreams of those who advocate for smart homes, smart cars, smart farms, smart robots, etc.? Achieving these dreams would require a strong IT infrastructure upon which future IoT user-applications can tackle the complexity of user-scenarios, the multiplicity of things, the sensitivity of IoT data, and the diversity of IoT devices, protocols, and standards. Such an IT infrastructure could, for instance, capitalize on the strengths of certain technologies like cloud and edge, though some treat cloud and edge as rivals. "Enterprises and vendors that don't focus on new demands driven by edge computing will become non-competitive. The edge will eat the cloud" (http://goo.gl/nxTNZ2).Prior to the rise of edge computing, 1 the cloud has been the model of choice for exposing resources (traditionally software, platform, and infrastructure) as services, which means shielding users from the complexity of the cyber-physical world's resources, describing resources in a machine-readable format so they can be discovered, and shifting the burden of managing resources internally to cloud providers in-return of a fee (pay-as-you-go). Gartner states that "by 2021, more than half of global enterprises already using cloud today will adopt an all-in cloud strategy" (http://goo.gl/m9MQXc). However,...
