Future of Wireless Networks: SDN/NFV, MEC and Network Slicing
Dr. Sassan AhmadiDirector of 5G Wireless Systems and Standards, Xilinx Inc.Lecturer at Stanford University
June 8, 2016
5G Network Architecture
Network Architecture Evolution
RAN Virtualization
Cloud-based Service Models
Cloud Server Models
SDN and NFV
– SDN Reference Architecture
– NFV Reference Architecture
– Virtualized Evolved Core Network (vEPC)
– SDN Deployment Models
– NFV and Coexistence with Legacy Networks
Virtualization and Network Slicing
Outline
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5G Network Architecture
…
Virtualized NW
Functions (vEPC)
Virtualized NW
Functions (vRAN)
E2E Control, Software Defined, Management and Orchestration
Server Farm and
Network Infrastructure
Cloud RANCloud Core
Fronthaul/Backhaul
Full Functional Base Station
MEC Server
(Edge Cloud)
NFVI
(Network Function Infrastructure)
Fronthaul
NGFI/CPRI Switch
A Virtualized, Programmable, Flexible Network with Edge Computing Capability based on Open and Standard Interfaces
CPRI
RRH
RRH
CPRI
RoE/CPRI
Various Baseband and Radio Functional Splits
Centralized
Distributed
Source: Xilinx
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Network Architecture Evolution
Source: NMC Consulting Group
Separation of Baseband and
Radio
Separation of Control Plane and
User Plane
Network Slicing and Virtualization
Wireless/Wired
Backhaul
Wireless/Wired
Fronthaul
Air-Interface
RAN Virtualization
Cloud RAN Use Cases (Flexible Functional Split)
RAN functions can be mapped
to VMs in different ways depending on the network
architecture and applications
Traditional BBU
L1
MAC
RLC
PDCP
Transport
S1
Fronthaul Connectivity
CPRI
RRC
L1-Low
MAC
RLC
PDCP
L1
L1 split
MAC
RLC
PDCP
S1
L1-High
vNIC
To RRH
VNF2
VNF1
VNF4 Transport
S1
RRC
VNF3
Transport RRC
Move to fronthaul switch or RRH
vNICVS
VS
L1
MAC
RLC
PDCP
Transport
S1
RRC
vNIC
To RRH
VS
VNF
L1
MAC
RLC
PDCP
S1
Transport RRC
vNICVS
To RRH
Apps
Hardware
Host OS
Hypervisor
Guest OS
Bin/Libs
Apps
VM
Bin/Libs
Apps
Container
Bin/Libs
Apps
Container
Hardware
Host OS
Bin/Libs
Apps
Bare Metal
Network and RAN Functions are Virtualized and Realized as Applications over Virtual Machines (VM)
GPP + Accelerator + Memory + Storage + Connectivity
RTOS
Next Generation BBU
Cloud-based Service Models
Source: Microsoft Azure
IaaS is a form of cloud computing that provides
virtualized computing resources over the Internet.
PaaS is a cloud computing model that delivers
applications over the Internet.
SaaS is a software distribution model in which applications are hosted by a
vendor or service provider and made available to customers over the
Internet.
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Cloud Server Models
Top of Rack
CPU
MEM Storage Acceleration
10/25/40G
CPU
MEM Storage Acceleration
10/25/40G
CPU
MEM Storage Acceleration
10/25/40G
Storage
10/25/40G
Storage
StorageStorage
…
Traditional Server Model
CPU
MEM Storage
CPU
MEM Storage 25/40/100G
CPU
MEM Storage
StorageStorage
StorageStorage
…
Acceleration
Acceleration
Acceleration
Acceleration
25/40/100G
25/40/100G
25/40/100G
25/40/100G
Disaggregated Server Model
PCIe or Ethernet
Top of Rack
PCIe or Ethernet
By separating critical components from one another, each resource can be upgraded or scaled independently. The disaggregation of hardware accelerators, enables sharing of accelerator resources across many computing or
networking blades, thus providing improved amortization of traditionally expensive components.
Server Connectivity Models
OVS with DPDK Running on
High Performance NFV NIC
Full VNF Portability Full Throughput
VNF VNF
Virtual Switchenables
VNF Portability
VNFFully
Portable
High Performance NFV NIC
Full Throughput Zero Packet Loss
OVS with DPDK Running on
Standard NIC
Full VNF Portability Limited Throughput
VNF VNF
Virtual Switchenables
VNF Portability
VNFFully
Portable
Standard NIC
Limited Throughput Packet Loss Issues
Direct Attach or SR-IOVRunning on
Standard NIC
No VNF PortabilityFull Throughput
VNF VNF VNF
Standard NIC
with SR-IOV
Virtual Switchbypassed
Not Portable
DPDK: Data Plane Development KitOVS: Open Virtual SwitchSR-IOV: Single Root Input Output VirtualizationVIM: Virtual Infrastructure Manager
Source: Napatech
SDN and NFV
Source: Cambridge Wireless Virtual Networks SIG
SDN decouples the software-based control plane from the hardware-based data plane of networking and switching
entities, moving control logic (and states) to logically centralized controllers.
NFV is the virtualization of network functions and services that could run on
general purpose hardware, allowing dynamically placing and moving these
functions in various locations of the network and service infrastructures.
Network Function Virtualization (NFV)
Concept
Software-Defined Network (SDN)
Concept
SDN and NFV are different concepts
Combination of SDN and NFV concepts
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SDN Reference Architecture SDN Applications are programs that communicate behaviors and needed resources with the SDN Controller via APIs. In addition, the applications can build an abstracted view of the network by collecting information from the controller for decision-making purposes. These applications could include networking management, analytics, or business applications used to run large data centers.
The SDN networking devices control the forwarding and data processing capabilities for the network. This includes forwarding and processing of the data path.
The SDN Controller is a logical entity that receives instructions or requirements from the SDN Application layer and relays them to the networking components. The controller also extracts information about the network from the hardware devices and communicates back to the SDN Applications with an abstract view of the network, including statistics and events about what is happening.
Source: ONF
NFV Reference Architecture
NFV End-to-End Reference Architecture
Operational/Business Support System
Source: ETSI
VNF is the software implementation of a network function which is capable of
running over the NFVI. It can be accompanied by an Element Management System (EMS).
The NFV Management and Orchestration, which covers the orchestration and lifecycle
management of physical and/or software resources that support the infrastructure
virtualization, and the lifecycle management of VNFs.
NFVI provides the virtual resources required to support the execution of
the VNFs. It includes commercial hardware, accelerator components
where necessary, and a software layer which virtualizes and abstracts the
underlying hardware
The entire NFV system is driven by a set of metadata describing service, VNFs and Infrastructure requirements, so
that the NFV Management & Orchestration systems can act
accordingly.
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Virtualized Evolved Core Network (vEPC)
Source: SDx Central
SDN Deployment Models
In the centralized model, a centralized manager with a single controller talks to distributed data planes. The route and data flow definitions are all done within that centralized manager. As networks scale and become more distributed, centralized control requires bigger, more costly systems with more powerful CPUs, larger storage and
a more resilient infrastructure with less failure tolerance, which makes it cumbersome and expensive.
In the distributed model, a centralized manager talks to combined distributed controller and data planes. The distributed SDN networks are evolutionary and easy to scale, as networks expand rather than the traditional
centralized model of rip and replace. It is also easier to apply policies to individual sections for specific applications with this approach.
Source: Open Networking Foundation
Migration path from the existing networks to full SDN implementation
NFV and Coexistence with Legacy Networks
Functional Block Architecture
Virtualization of Network Function
The VNF cannot exist in stand-alone form and relies on the host function for its existence and if the host function is interrupted, or disappears, then the VNF will be interrupted or disappear.
The container interface reflects this existence dependency between a VNF and its host function.
Source: ETSI
In a telecomm operator's environment, network functions are capable of remote configuration and management. In order to achieve this, the network functions have an interface, referred to as a north-bound interface, to a management and orchestration function. This management and orchestration function is often highly complex and composed of many distributed component parts.
The objective of NFV is to separate the virtualized network functions from the infrastructure, and this includes their management. The management and orchestration functions are divided between the management and orchestration of the network functions virtualization infrastructure (NFVI) and the management and orchestration of the VNFs.
NFV and Coexistence with Legacy Networks
Management and orchestration of virtualized network functions
Management and orchestration of network functions
Source: ETSI
Virtualization and Network SlicingNetwork operators like KT, SK Telecom, China Mobile, DT, KDDI and NTT DoCoMo, and also vendors like Ericsson, Nokia and Huawei are all recognizing Network Slicing as an ideal network architecture for 5G
It allows operators to slice one physical network into multiple, virtual, E2E networks, each logically isolated including device, access, transport and core network and dedicated for different types of
services with different characteristics and requirements. For each network slice, dedicated resources (like resources within virtualized servers, network BW, QoS, etc.) are guaranteed.
Mobile Broadband,
Massive MTC, and Ultra-
Reliable Low Latency
Communications require different type of features and networks in
terms of mobility, charging,
security, policy control, latency, reliability, etc.
Source: NMC Consulting Group
How Do We Implement E2E Network Slices?
Dedicated slices are created for services with different requirements and virtualized network functions are placed in different locations in each slice (i.e., Edge or Core cloud) depending on
services.
Edge Cloud (vMEC)
Core Cloud (vEPC)
DU UPCache Server
MVO Server
Internet
Access Management
Session Management
Mobility Management
Charging
Access Management
Session Management
DU UP V2X Server
Ultra-High-Density Services Slice
Telephony Services Slice
Massive MTC Services Slice
Ultra-Reliable MTC Services Slice
V2X Server
DU
CP/UPDU
IoT Server
SDN
Hypervisor Hypervisor
GPP + Accelerator GPP + Accelerator
Connectivity among VMs located in the edge and core clouds is provisioned by SDN
CP
TCP IMS
CP/UP
VM/VNF
UP: User PlaneCP: Control PlaneDU: Digital Unit (BBU)RU: Radio Unit (RRH)