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Misc: Introduction to ATSSS - Access Traffic Steering, Switching and Splitting


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This short presentation & video looks at 3GPP Release-16 feature ATSSS (Access Traffic Steering, Switching and Splitting)

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Misc: Introduction to ATSSS - Access Traffic Steering, Switching and Splitting

  1. 1. Introduction to ATSSS: Access Traffic Steering, Switching and Splitting @3g4gUK
  2. 2. ATSSS ©3G4G • We touched on ATSSS briefly in 5G & FMC presentation – In this one we will touch on some more details
  3. 3. Traditional Mobile Operation ©3G4G Voice (CS or PS) Data
  4. 4. Data over Wi-Fi ©3G4G Voice (CS or PS) Data
  5. 5. Data and Voice over Wi-Fi ©3G4G Voice (VoWiFi – PS only) Data C PS voice is just IP Packet Data
  6. 6. 5G Enables Multiple Data Paths ©3G4G Data C Data Data
  7. 7. Voice & Data are Independent of each other ©3G4G Data C Data Data VoNR (PS only)
  8. 8. ATSSS: Access Traffic Steering, Switching and Splitting ©3G4G • New Access Traffic Steering, Switching and Splitting (ATSSS) functionality has been designed in Release 16, which allows traffic steering across multiple accesses at a finer granularities than a PDU session. • The ATSSS feature is an optional feature in Release 16 both on the UE and the 5GC network • ATSSS introduces the notion of Multi Access PDU session, a PDU session for which the data traffic can be served over one or more concurrent accesses (3GPP access, trusted non-3GPP access and untrusted non-3GPP access).
  9. 9. ©3G4G ORSteering = = Best Network Selection Switching Splitting = = TO / FROM AND = Seamless Handover = Network Aggregation Improved End-User Experience
  10. 10. Important Points about ATSSS #1 ©3G4G • ATSSS needs 5G Core (5GC) • ATSSS allows the service provider (SP) to configure ATSSS rules and push them to the device via the 5GC. • These rules dictate how the device should utilize the 3GPP and Non- 3GPP access networks it may have available, specifically with respect to sending uplink traffic. • For downlink traffic, 5GC can provide rules to the UPF (User Plane Function) which dictate which access network should be used for which traffic flow.
  11. 11. Important Points about ATSSS #2 ©3G4G • Within the 5GC, control of ATSSS is largely handled by the PCF (Policy Control Function), whose responsibility it is to provide ATSSS rules to both the device and the SMF (Session Management Function) based on service provider policy. • The device/UPF could be configured with different “Steering Functionality” options, such as: • Higher Layer Steering Functionality • Lower Layer Steering Functionality (can be applied to all higher layer traffic types)
  12. 12. Non-3GPP Access Architecture Reference Model for ATSSS Support ©3G4G AMF SMF UPF DN N11 N4 N6 3GPP Access N2 N3 N1 Based on 3GPP TS 23.501 4.2.10-1: Non-roaming and Roaming with Local Breakout architecture for ATSSS support N3 N2 N1 PCF N7 UE MPTCP functionality ATSSS-LL functionality MPTCP Proxy functionality PMF MPTCP – Multi-Path TCP Protocol PMF – Performance Measurement Functionality
  13. 13. Higher Layer Steering Functionality ©3G4G • MPTCP (Multipoint Transmission Control Protocol) – carried out above IP in the protocol stack, allows the device to communicate with an MPTCP Proxy within the UPF to determine how TCP traffic associated with applications can be split, switched or steered.
  14. 14. Lower Layer Steering Functionality ©3G4G • Can be applied to all higher layer traffic types: • Active / Standby – for a given traffic flow, this will categorize one of the access networks (3GPP or non- 3GPP) as active and the other as standby. The standby access network will only be used for the traffic flow if the active is unavailable. • Smallest Delay – this steers a given traffic flow to the access network which has the smallest delay with respect to Round Trip Time. • Load Balancing – this splits a traffic flow across both access networks, based on a percentage split • Priority Based – this will steer a traffic flow to the highest priority access network, until that access network is considered to be congested. At this point, traffic can also be split towards the low priority access network.
  15. 15. KT tests ATSSS KT & Tessares successfully test ‘5G Low Latency Multi- Radio Access Technology’ in a Commercial 5G Network – Read the press release here. (Download slides from SlideShare) ©3G4G
  16. 16. Conclusion ©3G4G • Initial priority for the Service Providers (SPs) is to deploy 5G Core (5GC), starting next year • Once 5GC is in place, we will start seeing SPs looking to deploy advanced features like support for trusted & untrusted non-3GPP Access • Once they are in place, we will see ATSSS being implemented, tested and deployed. • Realistically, we will start seeing some operators use the feature in 2021/22
  17. 17. Further Reading on ATSSS ©3G4G • Mpirical: 5G ATSSS (This is the main reference for this video) • Tessares: 5G ATSSS solution • 3G4G: True Fixed-Mobile Convergence (FMC) with 5G • 3GPP TS 23.501 v16.1.0: System Architecture for the 5G System; Stage 2 • Whitepaper: Fixed-Mobile Convergence in the 5G era: From Hybrid Access to Converged Core - Massimo Condoluci, Stephen H. Johnson, Vicknesan Ayadurai, Maria A. Lema, Toktam Mahmoodi, Maria A. Cuevas, and Mischa Dohler (link) • Operator Watch Blog: How is KT Reducing the Latency of their 5G Network (link)
  18. 18. Thank You To learn more, visit: 3G4G Website – 3G4G Blog – Operator Watch – Connectivity Technology Blog – 3G4G Small Cells Blog – Follow us on Twitter: Follow us on Facebook: Follow us on LinkedIn: Follow us on SlideShare: Follow us on YouTube: ©3G4G