Towards an SDN-based Mobile Core Networks (MCN) Xueli An and Artur Hecker Huawei Technologies, European Research Center Munich Xueli.An@huawei.com and Artur.Hecker@huawei.com VDE/ITG-Fachgruppe 5.2.4, 5G System Architecture, Dec. 10. 2015 Huawei Technologies Duesseldorf GmbH
Contents MCN Evolution Path 4G SDN as D-Plane ETSI NFV + SDN + SDN enabled enb Full-SDN Evolution path SDN as an Interface to the Infrastructure ETSI NFV + SDN ETSI NFV + SDN + MEC From Theory to Practice: 5G on Testbed Huawei Technologies Duesseldorf GmbH 2
Current Generation (4G): LTE SAE / EPC Physical Network Logical Architecture RAN PGW CORE HSS RU, DU MME, SGW MME GTP-C PCRF enb GTP-U SGW PGW IP backhaul System Architecture: Pre-configuration: fixed infrastructure, fixed architecture, manual setup Single architecture: one size fits all LTE entities becoming bottlenecks (MME in C-plane, PGW in D-plane) Non-native transport: overlaying in both D-Plane and C-Plane Non-optimized service provisioning: packets are touched by many entities, user states are spread in multiple network elements Cost: All dedicated hardware, high CAPEX and high OPEX Huawei Technologies Duesseldorf GmbH 3
Evolution (1) SDN as an Interface to the Infrastructure Physical Network Logical Architecture RAN Central DC CORE HSS MME, S/PGW MME PCRF RU, DU enb SGW-C PGW-C SDN based backhaul (with GTP Support) GTP-U SDN CTRL SGW-U SDN CTRL PGW-U Virtualized network function (VNF) approach Core network function like MME, S/PGW-C are implemented as software and run on Commercial-Off-The-Shelf (COTS) hardware. Decoupled the MCN C- and D-plane. More dynamic flow distribution over the infrastructure SDN s advantages are not fully leveraged. SDN only sets flow paths for GTP-U data bearers Logical architecture is untouched. Same as conventional LTE. Directly map from physical box to virtual box Pre-configuration Single architecture: one size fits all Huawei Technologies Duesseldorf GmbH 4
Evolution (2) SDN as D-Plane: Get rid of GTP Tunnels Physical Network Logical Architecture RAN Central DC CORE HSS RU, DU SDN based backhaul (with GTP Support) MME, S/PGW enb IP flows MME SGW-C SDN CTRL SGW-U PCRF PGW-C SDN CTRL PGW-U GTP to flow mapping COTS Network Entity () Logical Architecture GTP-U is replaced by flow entries directly Native data plane transport: less overhead on the data plane The C-plane of the logical architecture is barely touched. Similar to conventional LTE. Huawei Technologies Duesseldorf GmbH 5 enb HSS MME GW-C SDN CTRL PCRF
Evolution (3): ETSI NFV + SDN Physical Network Logical Architecture RAN Central DC CORE HSS ETSI NFV MANO MME, S/PGW MME PCRF Orchestrator RU, DU enb GW-C VNF Manager SDN CTRL SDN based backhaul Virtualized Inf. Manager (VIM) Bring system agility Respond on-demand to the dynamic needs of the traffic and services running over it. Allows overcoming bottlenecks more easily The C-plane of the logical architecture is barely touched. Similar to conventional LTE. Extra management effort Huawei Technologies Duesseldorf GmbH 6
Evolution (4): ETSI NFV + SDN + SDN enabled enb Physical Network Logical Architecture RAN Central DC CORE HSS ETSI NFV MANO MME, S/PGW MME PCRF Orchestrator RU, DU enb GW-C VNF Manager SDN CTRL SDN based backhaul Virtualized Inf. Manager (VIM) A new functional split on enb -> enb + enb contains radio part and C-plane related functions Flow-related parts is controlled by SDN control apps. Native traffic distribution in the infrastructure, depending on the SDN capabilities The C-plane of the logical architecture is barely touched. Similar to conventional LTE. Extra management effort Huawei Technologies Duesseldorf GmbH 7
Evolution (5): ETSI NFV + SDN + MEC Physical Network Logical Architecture RAN Central DC CORE HSS ETSI NFV MANO RU Edge DC DU MME, SGW PGW enb MME GW-C PCRF Orchestrator VNF Manager SDN CTRL SDN based backhaul Virtualized Inf. Manager (VIM) Resource pooling at the edge. The C-plane of the logical architecture is barely touched. Enable C-RAN model. Similar to conventional LTE. Enable core network functions to be placed at the Extra management effort edge -> reduced C-plane latency -> Concept merging between the Core and the Edge Huawei Technologies Duesseldorf GmbH 8
Evolution (6): Programmable infrastructure - Full-SDN RAN Central DC SDN APP x Physical Network CORE MM: mobility mgmt CM: connectivity mgmt MM CM APPx Logical Architecture RU Edge DC AF SDN APP y SDI Control SDN based backhaul No fixed architectures anymore - architecture is a programme. Distributed system limits, potentially too complex to A programmable functional split realize? One unique control plane Performance-wise: carrier-grade? MCN with full programmability: no bottlenecks, flexibility, agility, etc. Huawei Technologies Duesseldorf GmbH 9
EPC vs. Full SDN MCN MM: mobility mgmt CM: connectivity mgmt 5G and beyond 4G MM CM APPx HSS 2020+ SDI Control MME GTP-C PCRF enb GTP-U SGW PGW 2015 Everything is event-based; events are dispatched from the infrastructure elements to capps. CP runs on the same infrastructure (in-resource ctrl). capps Pre-provisioned exchanges in both C- and D-Planes, realized as dynamically decide what to do. overlays Huawei Technologies Duesseldorf GmbH 10
MCN as Full-SDN High Level capps Conn. AAA Mobility Other 5G Apps Sanity Checks, Access Control, Quotas, Verifications Low Level capps QoS Sec SPF App1 App2 AppN Carrier Grade SDN Abstractions Controller API (e.g. RESTful API) Controller North interface Catalog Topology Allocs Control Plane Configuration Infrastructure control Compute and storage resource control Intelligent orchestration Controller South interface TCONF e.g. OpenFlow +Extensions Others Discovery, failure detection, control traffic preservation, etc Higher Functions Auto-organization Logical abstractions, slices, overlays, virtual objects Infrastructure (Switches/Routers, Hosts with Hypervisors, Storage) Infrastructure layer Huawei Technologies Duesseldorf GmbH 11
MCN as Full-SDN High Level capps Conn. AAA Mobility Other 5G Apps Applications Sanity Checks, Access Control, Quotas, Verifications Low Level capps Abstractions QoS Sec SPF App1 App2 AppN OS Utilities Controller API (e.g. RESTful API) Controller North interface Carrier Grade SDN Catalog Topology Allocs Control Plane Configuration Infrastructure control Compute and storage resource control OS Kernel Intelligent orchestration Controller South interface TCONF e.g. OpenFlow +Extensions Others Discovery, failure detection, control traffic preservation, etc Higher Functions Auto-organization Logical abstractions, slices, overlays, virtual objects Hardware or Distributed Resources Infrastructure (Switches/Routers, Hosts with Hypervisors, Storage) Infrastructure layer Huawei Technologies Duesseldorf GmbH 12
From Theory to Practice: 5G on Testbed MCN support: service request, mobility, paging, etc. It could measure! Controller Server SDN APP Log T2 (Request to Push Flows) Floodlight Controller Log T1 (Packet_IN) Log T4 (Last DL Flowmod) Log T3 (First UL Flowmod) Emulation Server (Mininet) 1 3 2 4 We pursue a radical goal of tuneless, anchor-less and NFV-less mobility support in SDN It also scales! Huawei Technologies Duesseldorf GmbH 13
From Theory to Practice: 5G on Testbed Core switch 1 3 Location for SGW/PGW 2 4 Destination device region Source device region Huawei Technologies Duesseldorf GmbH 14
Final Word General programmability = major vulnerability The very feature bears the main risk What will happen when thousands of programmable entities will be waiting in a large-scale environment for close-to-realtime programmatic control by other virtual entities? Openness => Error-proneness How to efficiently support access control for multi-tenancy scenario? How to pursue 6-9 reliability and towards 0 latency? Huawei Technologies Duesseldorf GmbH
Copyright 2014 Huawei Technologies Duesseldorf GmbH. All Rights Reserved. The information in this document may contain predictive statements including, without limitation, statements regarding the future financial and operating results, future product portfolio, new technology, etc. There are a number of factors that could cause actual results and developments to differ materially from those expressed or implied in the predictive statements. Therefore, such information is provided for reference purpose only and constitutes neither an offer nor an acceptance. Huawei may change the information at any time without notice.