HEPiX Network Functions Virtualisation Working Group Report

High Energy Physics (HEP) experiments rely on the networks as one of the critical parts of their infrastructure both within the participating laboratories and sites as well as globally to interconnect the sites, data centres and experiments instrumentation. Network virtualisation and programmable networks are two key enablers that facilitate agile, fast and more economical network infrastructures as well as service development, deployment and provisioning. Adoption of these technologies by the HEP sites and experiments will allow them to design more scalable and robust networks while decreasing the overall cost and improving the effectiveness of the resource usage. The primary challenge we face is ensuring that WLCG and its constituent collaborations will have the networking capabilities required to most effectively exploit LHC data for the lifetime of the LHC. Network virtualisation and programmable networks are nowadays quite common in the commercial clouds and telco deployments and have also been deployed by some of the Research and Education (R&E) network providers to manage Wide-Area Networks (WAN), but there are only few HEP sites pursuing new models and technologies to build up their networks and data centers and most of the existing efforts are currently focused on improvements within a single domain or organisation, usually motivated by the organisation-specific factors. Therefore, most of the existing work known in the area is usually site or domain-specific. In addition, there is a significant gap in our understanding of how these new technologies should be adopted, deployed and operated and how the inter-play between LAN and WAN will be organised in the future. While it’s still unclear which technologies will become mainstream, it’s already clear that software (software-defined) and programmable networks will play a major role in the mid-term. With the aim to better understand the technologies and their use cases for HEP a Network Functions Virtualisation Working Group (NFV WG) has been formed within the High Energy Physics Information Exchange (HEPiX). In the initial phase, the working group was focusing on identifying the work already done, looking at the existing projects and their results as well as better understanding the various approaches and technologies and how they can be helpful for the HEP use cases. This report provides a summary of this phase and in addition attempts to identify key areas that require further work that could be discussed within the community to find synergies and understand where existing efforts should be focused. This document presents a technical overview of the existing approaches in network virtualisation and programmable networks. It starts by explaining how current paradigm shift in the computing and clouds is impacting networking and how this will fundamentally change the ways networks are designed in the data centers and sites. Cloud native networking approaches involving new topologies, network disaggregation and virtualisation have been identified as primary drivers that will impact data centre networking, which will in turn impact how data centres will be inter-connected in the future. In the second chapter which is devoted to the WAN, capacity sharing, network provisioning and software-defined approaches are discussed and key projects in the area are highlighted. This is complemented by a brief survey on the mid-term plans of the major R&E providers. The report concludes with a proposed projects areas and milestones that should serve as input in discussing the potential future work in this area. While there are many technology choices that need discussion and exploration, the most important thing is ensuring the experiments and sites collaborate with the RENs, network engineers and researchers to develop, prototype and implement a useful, agile network infrastructure that is well integrated with the computing and storage frameworks being evolved by the experiments as well as the technology choices being implemented at the sites and RENs