  Hackers target their attacks on the most vulnerable parts of a system. A
system is therefore only as strong as its weakest part, similar to the Cannikin
Law, which states that the capacity of a barrel of water depends on the height
of the shortest rather than the longest piece of wood. To ensure the security
of 5G networks, we first need to understand the overall 5G architecture and
examine the potential threats instead of merely setting up a firewall. However,
5G networks will have tremendous coverage. The development of 5G techniques
require extensive resources, leading to intense competition between countries
attempting to develop 5G networks. Many outstanding papers discuss the
techniques for developing specific aspects of the 5G architecture, but to the
best of our knowledge, few provide an overview of a complete 5G network. This
presents us with a difficult situation because we need to consider the overall
architecture to ensure the security of 5G networks. To address that problem, in
this paper we provide essential guidelines for understanding the architecture
of 5G. We introduce 5G scenarios, outline the network architecture, and
highlight the potential security issues for the various components of a 5G
network. This paper is intended to facilitate a preliminary understanding of
the 5G architecture and the possible security concerns of the various
components. The end to end (E2E) 5G network architecture is composed of a
next-generation radio access network (NG-RAN), multi-access edge computing
(MEC), virtual evolved packet core (vEPC), a data network (DN) and a cloud
service. Network slicing (NS), network function virtualization (NFV), NFV
Management and Orchestration (MANO) and software-defined networking (SDN) are
also important techniques for achieving 5G network architectures.
