MEC (Multi-access Edge Computing) has been developed as a solution for network operators, enabling the extension of telecommunications infrastructure with servers offering computing resources to users and service providers (including cloud service providers). The relevant standards are developed by the ETSI standardization organization within the ISG MEC (Industry Specification Group on Multi-access Edge Computing) working group. The ETSI MEC solution is now an integral part of the 5G network infrastructure, but it can also be used in LTE networks and other access networks. It should be emphasized that the MEC technique is a significant step in the development of telecommunications infrastructure towards a future, integrated communication and computing infrastructure.
Parallel to the standardization work, research is carried out on the specification of mechanisms and algorithms for MEC systems. In particular, as part of projects related to the implementation of NFV systems or orchestration in cloud systems, working groups were established to implement extensions of these systems and to support the computing technique at the network edge. Examples of such initiatives are: Open NFV Edge, Edge Automation through ONAP, OpenStack Edge, or LinuxFoundation Edge. The solutions proposed by the above projects are usually extensions of the architecture of orchestration systems developed for NFV backbone networks or cloud applications that offer the possibility of orchestrating applications at the edge of the network. Therefore, these solutions are not fully compatible with the ETSI MEC architecture.
In addition, research projects aimed at developing prototypes of MEC systems fully compliant with ETSI standards have been developed,. In particular, the SYMEC, implemented an ETSI- compliant MEC platform on the low-energy ARM architecture.
Polish SLICES representatives have been involved in implementation of the SYMEC platform. The SYMEC architecture is presented on the figure below. The architecture is modeled on the architecture of the network edge computing system proposed by the ETSI MEC standardization group.
Figure 1 The SYMEC architecture
The SyMEC architecture includes six core components:
Based on the experience of designing the SyMEC system, it should be noted that the ETSI MEC architecture is only an abstract model of the edge computing system. This model requires significant modifications and additions, which results from the fact that the MEC system is one of the subsystems of the complex ecosystem of the operator’s infrastructure and must be fully integrated with other subsystems of this infrastructure, such as the OSS / BSS subsystem or the management subsystem. Moreover, the use of an abstract resource model is advantageous for the operation of the orchestrator or the user interface as it allows to hide the physical realization of the objects, which simplifies the control methods used in a heterogeneous system composed of different computing clusters. However, the specification and implementation of the MEC platform manager, VIM manager, application repository or modules for cooperation with access networks largely depends on the virtualization platform used and network techniques used. The basic element that maps the world of abstract objects used in the model to their physical representation is the MEC platform manager together with the management system modules. It should also be emphasized that the container virtualization platform based on Docker and Kubernetes (k8s) tools used in the prototype also forced the extension of the MEC application descriptor in relation to the description defined by ETSI and influenced the application image repository.
In order to ensure cooperation with other operator systems, the SyMEC architecture maintains full compliance of external contacts with the ETSI MEC and TMF standards. In particular, the Mm1 interface between the orchestrator and the OSS / BSS system is compatible, which allows initiating the start / stop of an MEC application instance or registration / deletion of a new MEC service / application. The SyMEC asset description is also compliant with TMF standards, allowing easy integration of SyMEC with operator management systems. In addition, the MEC application API program interface is compliant with ETSI standards to allow easy implementation of MEC applications developed by third party developers. The remaining contacts were defined using the open REST APIs or, as in the case of the Mm6 contact, the API defined in the Kubernetes tool was used.
To sum up, the SyMEC architecture, compared to the ETSI MEC architecture, has been extended with the following elements:
The developed prototype of the SyMEC system was implemented in the nationwide research network PL-LAB 2020, which made it possible to integrate MEC nodes with various access networks and conduct tests in conditions similar to those prevailing in operating networks. The prototype was installed in four locations, i.e. in Gdańsk (Gdańsk University of Technology), Poznań (Poznań Supercomputing and Networking Center), Wrocław (National Communications Institute – Research Institute) and in Warsaw (Warsaw University of Technology), as presented on the figure below.
Figure 2 Implementation of the SyMEC system in the nationwide research network PL-LAB 2020
Two MEC servers were installed at each site. One of them is the MEC server developed in the project with an ARM64 processor, and the other MEC server was built using a typical x86 server. The heterogeneous environment of the computing cluster allowed for the installation, operation and interoperability of MEC applications designed for ARM64 and x86 systems. In particular, the SyMEC node in Gdańsk was integrated with the extensive WLAN network installed on the campus of the Gdańsk University of Technology. The SyMEC node in Wrocław has been integrated with experimental LTE (4G) and 5G networks built with the use of open-source software. In this case, due to restrictions on the licensed frequency band, the base stations and terminal terminals were installed in the anechoic chamber. In addition, in the nodes located in Warsaw and Poznań, SyMEC servers were integrated with LAN / WLAN local networks, making MEC applications and SyMEC system resources available to users of these networks for research on MEC technology.
The developed installation includes the full functionality of the developed SyMEC system, which enables research on the MEC technique. It should be emphasized that the developed prototype and pilot installation include the full functionality of the developed SyMEC system, integrate MEC servers developed as part of the project (based on arm64 processors), as well as servers based on x86 processors, enable MEC applications to use hardware acceleration and parallelize calculations based on o GPU processors.
 OPEN NFV edge project , https://wiki.opnfv.org/display/EC/Edge+ cloud.
 ONAP Project: Edge automation through ONAP, https://wiki.onap.org/ display/DW/Edge+Automation+through+ONAP.
 OpenStack project: Edge computing, https://www.openstack.org/edge- computing/.
 LF EDGE project: Building an open source framework for the edge, https://www.lfedge.org/.
 5G City Project, https://www.5g.eu/.
 Openness Project, https://www.openness.org/.
 SYMEC Project, https://www.symec.com.pl/.
 ETSI, Multi-access Edge Computing (MEC); Framework and Reference Architecture, ETSI GS MEC 003 V3.1.1, March 2022.
 Docker: https://www.docker.com/
 Kubernetess “Production-Grade Container Orches-tration”, https://kubernetes.io
 ETSI, Multi-access Edge Computing (MEC); General principles, patterns and common as-pects of MEC Service APIs, ETSI GS MEC 009 V3.1.1, June 2021