ETCP Core Network Architecture 2 — Questions and Answers
Question 1: In Ericsson's 5GC, which network function enforces policy rules and manages QoS for PDU sessions?
- SMF
- NEF
- PCF (Correct answer)
- NSSF
Correct answer: PCF
The PCF (Policy Control Function) defines and distributes QoS and charging policies to the SMF and AMF for session and access management.
Question 2: What does Network Slicing allow operators to do in Ericsson's 5G core?
- Physically separate antenna sectors
- Create multiple logical networks on shared infrastructure, each with tailored SLAs (Correct answer)
- Allocate dedicated spectrum per user
- Split base station software into microservices
Correct answer: Create multiple logical networks on shared infrastructure, each with tailored SLAs
Network Slicing enables operators to instantiate multiple virtual networks (slices) on one physical 5GC, each customized for different services like eMBB, URLLC, or mMTC.
Question 3: In Ericsson's cloud-native 5G core, what does the SBI (Service-Based Interface) use as its communication protocol?
- Diameter
- SOAP/XML
- HTTP/2 with JSON (RESTful) (Correct answer)
- SS7
Correct answer: HTTP/2 with JSON (RESTful)
5GC network functions communicate over the SBI using HTTP/2-based RESTful APIs with JSON encoding, replacing Diameter and SS7 from earlier generations.
Question 4: What is the purpose of the UDR (Unified Data Repository) in Ericsson's 5G core?
- Stores raw subscriber data that can be accessed by UDM, PCF, and other NFs (Correct answer)
- Manages physical data center resources
- Provides DNS resolution for NF discovery
- Handles inter-PLMN roaming agreements
Correct answer: Stores raw subscriber data that can be accessed by UDM, PCF, and other NFs
The UDR is a centralized data store that holds subscription data, policy data, and structured data for consumption by other 5GC NFs via standardized APIs.
Question 5: In Ericsson EPC, what does the HSS store?
- Real-time call detail records
- Subscriber identity, authentication keys, and service profiles (Correct answer)
- Network topology and routing tables
- Cell-level radio measurements
Correct answer: Subscriber identity, authentication keys, and service profiles
The HSS (Home Subscriber Server) is the master database storing subscriber identities (IMSI/MSISDN), authentication credentials, and service subscription data.
Question 6: Which Ericsson core solution supports Voice over LTE (VoLTE) by providing IMS anchoring?
- Evolved Packet Core (EPC) with IMS (Correct answer)
- NodeB RNC pair
- SGSN/GGSN stack
- SDN Controller only
Correct answer: Evolved Packet Core (EPC) with IMS
VoLTE requires the EPC for data bearer setup and an IMS layer for SIP-based voice session control, working together as an integrated platform.
ETCP Core Network Architecture 2
In Ericsson's 5GC, which network function enforces policy rules and manages QoS for PDU sessions?