5G III Flashcards
What are the key communication changes with 5G?
The network functions are becoming software only
Network functions can be installed in compute nodes at the edge of the network
Development of new types of local access networks (and integrating existing ones)
What are the main advantages of the 5G evolution?
Communication can be executed through dedicated networks
Local access networks can use carrier-grade network technologies
Network functions can be placed in different network locations
How is the 5G system seen from a network functions perspective?
The 5G system is a distributed system
The 5G system is a software system
New mechanisms for ensuring the resilience and the security
Why use a 5G system instead of a 4G one?
Network functions can be customized depending on the communication requirements
The system can use the infrastructure available at the location
The system can integrate with different access network
or the local access networks
Describe the high-level functionality of a 5G system
Security (Data plane)
Access Control (Data plane)
Transparency to applications (Data plane)
Basic Connectivity (Data plane)
Authentication and authorization (Control plane)
Mobility Management (Data plane)
What are the key 5G network principles?
Control-User Plane Separation (CUPS)
Modularized function design
Minimize the dependencies between access and core
Enable direct interaction between functions as much as possible
Support a unified authentication framework
Support capability exposure
Support concurrent access to local and centralized services
Describe the network functions AMF
Represents the main control entity within the 5G system
Describe the network functions SMF
Represents the separate management functionality for sessions
Describe the network functions UPF
Represents the data plane functionality of the 5G System
Describe the network functions PCF
Represent the policy-based functionality of the network
How is session continuity achieved in 5G
Full session continuity: IP connectivity maintained regardless of UE mobility events
Break-before-make: The network instructs the UE to immediately reconnect and disconnects it.
Make-before-break: A new connectivity is established before the previous is release
How is QoS achieved in 5G?
prioritizing traffic flows and providing preferential forwarding for higher-priority packets
NAS
NAS: used to communicate with both the AMF (NAS-MM) and SMF (NASSM)
NG-AP
NG-AP protocol interconnects the NG-RAN with the AMF and UPF
GTP-U
5G AN will speak GTP-U towards the network
State modes for UE and AMF
Registration Management state machine
Connection management state machine
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Describe the integration of non-3GPP accesses
An interworking gateway enabling the anchoring of the non-3GPP networks into the 5G system
What is the Service Based Architecture?
SBA represents a radical re-thinking of the packet core network towards an efficient micro-services architecture
Compare the service-based architecture with the classic architecture
Classic Architecture
i. Based on telecom protocols
ii. Easy to develop starting from existing architecture
iii. Naturally integrating with the 5G RAN
iv. Easy to migrate and interoperate with LTE
Service Based Architecture
i. Based on optimized internet protocols
ii. Easy to interact with the service administrator and application functions
iii. Following the micro-services approach
iv. Using a uniform easy to automate protocol in the control plane
v. Maintains most of the complexity
What are the Service Based Architecture specific network functions? Please describe them
Network Exposure Function (NEF): Provides the interworking with third party functionality
NF Repository Function (NRF): Acts as a network discovery function for dynamic network infrastructures
Network Data Analytics Function: Acts as a new insight component, taking pre-emption on events
What are the interactions between network functions (services) in SBA?
“Request-Response” − Based on the producer-consumer model
“Subscribe-Notify” − Based on an event-based mechanism − May include implicit subscriptions
SMS
SMS messages are passed through the N1 interface to the AMF
AMF will have to forward them to the SMSF which on its turn will forward them appropriately to the next hop
location services
The Location Management Function (LMF) acquires location information with different granularity from the AMF
AMF receives the information on the location from the RAN (not from the UE!)
Describe the RAN flexibility of 5G, which other accesses can be integrated, how does the integration look like for each
Fixed Wireless Access: Providing Fixed-like connectivity over the wireless access
OTT 5G: 5G networks are flexible enough to support as to be transported over other access networks
Non-3GPP accesses: The UE must be able to create NAS messages and transmit them through the available accesses
Integrated Access Backhaul: Intermediary CPE-like node proxying the connectivity for other UEs
Satellite direct access: Providing a Non-Terrestrial Network for 5G with gNB at Hub Location
