towards an sdn-based mobile core networks (mcn) towards an sdn-based mobile core networks (mcn)...

Huawei Technologies Duesseldorf GmbH

Towards an SDN-based

Mobile Core Networks (MCN)

Xueli An and Artur Hecker

Huawei Technologies, European Research Center Munich

[email protected] and [email protected]

VDE/ITG-Fachgruppe 5.2.4, “5G System Architecture”, Dec. 10. 2015

mailto:[email protected]

mailto:[email protected]

Huawei Technologies Duesseldorf GmbH 2

Contents

MCN Evolution Path

From Theory to Practice: 5G on Testbed

4G

SDN as an Interface to the Infrastructure

SDN as D-Plane

ETSI NFV + SDN

ETSI NFV + SDN + SDN enabled eNB

ETSI NFV + SDN + MEC

Full-SDN

Evolution path


Logical Architecture

Current Generation (4G): LTE SAE / EPC

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

RAN CORE

MME, SGW

PGW

RU, DU

PGWSGW

MME

eNB

PCRF

HSS

GTP-U

GTP-C

Physical Network

IP backhaul


Evolution (1) SDN as an Interface to the Infrastructure

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


GTP-U

RAN CORE

RU, DU

Physical Network

SDN based backhaul (with GTP Support)

Central DC

MME, S/PGW

SGW-C

MME

eNB

PCRF

HSS

PGW-C

SGW-U PGW-U

SDN CTRL

SDN CTRL

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


Evolution (2) SDN as D-Plane: Get rid of GTP Tunnels

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.


SGW-C

MME

eNB

PCRF

HSS

PGW-C

SGW-U PGW-U

SDN CTRL

SDN CTRL

GTP to flow mapping

NE NE

COTS Network Entity (NE)

RAN CORE

RU, DU

Physical Network

SDN based backhaul (with GTP Support)

Central DC

MME, S/PGW


GW-C

MME

eNB

PCRF

HSS

NE NE

SDN CTRL

IP flows



Evolution (3): ETSI NFV + SDN

Bring system agility

Respond on-demand to the dynamic needs of

the traffic and services running over it.

Allows overcoming bottlenecks more easily

Orchestrator

VNF Manager

Virtualized Inf. Manager (VIM)

ETSI NFV MANORAN CORE

RU, DU

Physical Network

SDN based backhaul

Central DC

MME, S/PGW

The C-plane of the logical architecture is barely touched.

Similar to conventional LTE.

Extra management effort

GW-C

MME

eNB

PCRF

HSS

NE NE

SDN CTRL



Evolution (4): ETSI NFV + SDN + SDN enabled eNB

A new functional split on eNB -> eNB’ + NE

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

Orchestrator

VNF Manager


ETSI NFV MANORAN CORE

RU, DU

Physical Network

SDN based backhaul

Central DC

MME, S/PGW




NE

GW-C

MME

eNB’

PCRF

HSS

NE NE

SDN CTRL



Evolution (5): ETSI NFV + SDN + MEC

Resource pooling at the edge.

Enable C-RAN model.

Enable core network functions to be placed at the

edge -> reduced C-plane latency -> Concept merging

between the “Core” and the “Edge”

RAN CORE

RU

Physical Network

SDN based backhaul

Edge DC

Central DC

DUMME, SGW

PGWOrchestrator

VNF Manager


ETSI NFV MANO




NE

GW-C

MME

eNB’

PCRF

HSS

NE NE

SDN CTRL



Evolution (6): Programmable infrastructure - Full-SDN

No fixed architectures anymore - architecture is a programme.

A programmable functional split

One unique control plane

MCN with full programmability: no bottlenecks, flexibility,

agility, etc.

RAN CORE

RU

Physical Network

SDN based backhaul

Edge DC

Central DC

AFSDN APP y

SDN APP x

Distributed system limits, potentially too complex to

realize?

Performance-wise: carrier-grade?

NE NE

SDI Control

NE

MM CM APPx…

MM: mobility mgmtCM: connectivity mgmt


EPC vs. Full SDN MCN

4G

PGWSGW

MME

eNB

PCRF

HSS

GTP-U

GTP-C

2015

2020+

• Everything is event-based; events are dispatched from the infrastructure elements to cApps.• CP runs on the same infrastructure (in-resource ctrl). cAppsdynamically decide what to do.• Pre-provisioned exchanges in both C- and D-Planes, realized as

overlays

5G and beyond

NE NE

SDI Control

NE

MM CM APPx…

MM: mobility mgmtCM: connectivity mgmt


Infrastructure (Switches/Routers, Hosts with Hypervisors, Storage)

Logical abstractions, slices, overlays, virtual objects

Higher Functions

MCN as Full-SDN

Infrastructure

control

e.g. OpenFlow

Controller API (e.g. RESTful API)

“Controller North interface”

QoS Sec SPF App1 App2 AppN

Configuration

NETCONF

AllocsCatalog

Compute and storage

resource control

Others

“Controller South interface”

Discovery, failure detection, control traffic preservation, etc

Auto-organization

+Extensions

Low Level cApps

Topology

High Level cAppsAAA Mobility Other 5G AppsConn.

Sanity Checks, Access Control, Quotas, Verifications

Abstractions

Infrastructure layer

Carrier Grade SDN

Intelligent

orchestration

Control Plane


Infrastructure (Switches/Routers, Hosts with Hypervisors, Storage)

Logical abstractions, slices, overlays, virtual objects

Higher Functions

MCN as Full-SDN

Infrastructure

control

e.g. OpenFlow

Controller API (e.g. RESTful API)

“Controller North interface”

QoS Sec SPF App1 App2 AppN

Configuration

NETCONF

AllocsCatalog

Compute and storage

resource control

Others

“Controller South interface”

Discovery, failure detection, control traffic preservation, etc

Auto-organization

+Extensions

Low Level cApps

Topology

High Level cAppsAAA Mobility Other 5G AppsConn.

Sanity Checks, Access Control, Quotas, Verifications

Abstractions

Infrastructure layer

Carrier Grade SDN

Intelligent

orchestration

Control Plane

“Hardware” or Distributed Resources

OS Utilities

OS Kernel

Applications



We pursue a radical goal of tuneless, anchor-less and NFV-less mobility support in SDN

MCN support: service request, mobility, paging, etc.

1

2

3

4

Emulation Server (Mininet)

Log T1(Packet_IN)

Log T2(Request to Push Flows)

Log T3 (First UL Flowmod)

Log T4 (Last DL Flowmod)

Floodlight Controller

SDN APP

Controller Server

It could measure!

It also scales!



1

2

3

4

Source device region

Destination device region

Core switch

Location for SGW/PGW

Huawei Technologies Duesseldorf GmbH

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”?

Copyright©2014 Huawei Technologies Duesseldorf GmbH. All Rights Reserved.

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results, future product portfolio, new technology, etc. There are a number of factors that could cause actual results and developments to differ materially

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towards an sdn-based mobile core networks (mcn) towards an sdn-based mobile core networks (mcn)...

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