Dedicated edge computing node deployments are seen today for evolving vertical sectors like manufacturing, transportation logistics and smart city gateways, while their number is expected to be significantly increased with the advent of new user-oriented services. Fog computing on the other hand, relies on larger processing nodes (e.g. mini-DCs) deployed in between the edge and the cloud segments of the network, allowing the sharing of infrastructure and computing resources among many attached subnetworks, hosting a variety of shared software services, similar to what the cloud offers but at a downscaled local level. Fog computing, (which is better denoted as near-edge computing in contrast to the far-edge computing described above) provides a more pragmatic approach, for a number of services which can rely on moderate latency requirements while being benefited from better deployment economics due to its resource sharing principles. It is noted that the typical 5G concept that relies on a pool of collocated BBUs at the central office (CO) site which are then connected to their remote radio head (RRH) units over the operator’s fronthaul infrastructure, enables essentially a type of fog computing deployment with the additional collocation of processing units attached to the base-band unit (BBU) pool. Recently formed partnerships between major cloud service operators and telecom operators are planning to realise this concept as a step forward to bring edge computing service deployment [[i]].
Despite the move of the cloud service providers closer to the edge, the distributed edge computing concept at the end-user site is still a necessity for fulfilling advance 5G requirements in terms of reliability and security in addition to ultra-low latency. This is applicable for a number of envisioned services primarily in manufacturing, automated mobility and any critical services such as eHealth and public protection and disaster relief (PPDR). In addition the sharing of edge computing nodes over the telecom operator infrastructure provides a new powerful business model through which the infrastructure owner and the independent end-users, application developers and service providers can be mutually benefited [[ii]], while the operator may easily expand its portfolio towards new type of tailored user-centric services [[iii]].
Figure 1 – Envisioned 5G system from the end-user to the fog/edge computing level and the cloud level at the core, with intelligent network control and service deployment and monitoring capabilities per level
According to the Int5Gent vision, which is highly supported by its telecom operator partners and is depicted in Figure 1, the edge and fog computing nodes coexist in a 5G fronthaul-backhaul infrastructure and support the vertical services and IoT devices at the attached access networks. The edge/fog level is composed by a diverse type of nodes and infrastructures with different processing capabilities, split in general into pure edge nodes (e.g. industrial or enterprise nodes, smart city or smart home gateways, private WiFi infrastructure servers) and fog-based service delivery nodes (e.g. mini-DCs, application servers, content delivery and data storage nodes). A special case is the node attached to the pool of BBUs handling the information processing of the mobile end users in the RAN. The overall 5G system is controlled by a network orchestrator with distributed edge/fog node management capabilities and centrally located application deployment and monitoring, which is also linked to the cloud for the delivery of high level processes such as web services and access to data pools.
What is though important in such a network, is the capability on one hand to seamlessly interconnect access nodes supporting any type of IoT device and related services over a bandwidth flexible and adaptive fronthaul/backhaul infrastructure and on the other hand to control and manage the network and computational resources, as well as orchestrate the lifecycle of the deployed service functions. This necessitates key advances in both the hardware level and the network and service orchestration level that are summarized below and constitute the main innovation targets of the envisioned 5G system platform.
[i] Business Insider, Hirsh Chitkara – AWS’s new partnership with network operators will help enable latency-sensitive 5G applications, 5/12/19
[ii] STL partners – Edge Computing: 5 viable telco business models , Nov. 2017