# A Systematic Survey on 5G and 6G Security Considerations, Challenges, Trends, and Research Areas
## 3 5G Security Architecture: A Systematic Approach
### Radio Access Network
#### 3.2.6 Network Slicing  
As 5G has the ability to handle many different use cases for the end user, it becomes necessary for it to provide a mechanism to control and track these different usage requirements in order to maintain fairness and QoS on the network. This strategy is called network slicing. Physical network resources are partitioned into multiple logically isolated networks, such that each'slice' can provide specific services corresponding to the usage requirements of the users' application [72]. A network slice is an independent virtual network that isolates resources, data flows, security features, network structure, and a clear and established QoS standard. These slices are segregated from one another and offer services to subscribers based on their specific requirements [73; 74]. An important concept of network slicing is its method of isolating and allocating resources for all users. The authors of [75] point out three vital pillars of network slicing, in terms of isolation, which are summarized below. 1. Performance: Every slice is designed to meet specific service requirements. In order to protect the performance of one slice compared to other concerns on the network, there must be mechanisms in place to ensure that requirements are met as best as possible under changing network conditions while ensuring that security is not sacrificed in the process and without impeding the operations of other slices. 2. Security and Privacy: Faults or attacks impacting one slice must not impact another slice. Every slice must, therefore, provide its own independent security functions that prohibit unauthorized read or write access to configuration/management/accounting information. 3. Management: Each slice is seen as a separate network, and to achieve isolation, consistent policies and mechanisms need to be defined at the virtualization layer. The policies describe how different manageable entities must be separated from each other while the mechanisms within the system execute the protocols and enforce the defined policies. The author states that the interplay of both virtualization and orchestration is necessary. Network slicing security is of great importance. In an article published by 3 GPP [76], and referencing 3 GPP TS 33.501 [2], the author offers a helpful perspective on the importance of creating, updating, and deleting network slices securely, which is summarized below. 1. Mutual authentication * Implemented between the management service consumer (the entity using or consuming the management services) and the management service producer (the entity providing the management services). * Transport Layer Security (TLS) is used to secure the communications * Designed to prevent unauthorized actions at the exposed management interfaces
2. Protection of management * Interactions between the management service consumer and producer are secured via TLS. * TLS includes protections such as: * Confidentiality Protection: Keeping the message exchanges confidential and encrypted; * Integrity Protection: Awareness that the data have not been changed or tampered with; * Replay Protection: Preventing the unauthorized replaying of previously captured messages to commit unauthorized actions. 3. Authorization of management * Management service consumers are authorized by the management service producer by way of an OAuth (Open Authorization) [77] mechanism. * Operators' local policies are taken into account during authorization. * Only specific authorized services are granted to the consumer. UE access to a network slice is also covered in the article. A secure handshake needs to occur as a UE needs to communicate which slice to operate on with the Core Network. This happens by way of the Non-Access-Stratum (NAS) Signaling and Access-Stratum (AS) Signaling. Any information is always sent over NAS regarding a network slice after NAS security is established. Network slicing has changed the way the telecommunication industry views network operations.