LT LTE/ E/EPC EPC Ar Archite itectur cture e fo for r On-De - - PowerPoint PPT Presentation

France Telecom - Orange confidential

Ne New Control Pla trol Plane e in in 3GPP 3GPP LT LTE/ E/EPC EPC Ar Archite itectur cture e fo for r On On-De Deman mand d Connec ectiv tivity ity Se Serv rvic ice

Siwar BEN HADJ SAID¹, Malla la Reddy SA SAMA¹, Karine GUILLOUARD¹, Lucian SUCIU¹, Gwendal SIMON², Xavier LAGRANGE² and Jean Marie BONNIN² ¹Orange Labs, France ²Télécom Bretagne, France

IEEE CloudNet’13 San Francisco, USA 11-13 Nov 2013

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Outline

I.

Introduction & Background

II.

OF-Based LTE/EPC Architecture

I. Architecture Description II. Data Plane Establishment Procedure

III.

On-Demand Connectivity Service

I. Resiliency II. Load Balancing

IV.

Implementation Challenges

V.

Conclusion & perspectives

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Introduction

• Mobile data traffic has

been growing at an unprecedented rate over the last few years.

• Huge data traffic increase

and may cause signaling storms in the network.

– Smartphones and tablets generate 40% of the data traffic and 99%

• f the signaling traffic.

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LTE/EPC Architecture

External Packet Data Networks eNB UE S1(GTP-U) S5 (GTP-U)

SGi

S1 (S1-AP) S11 (GTP-C) S6a (Diameter) S5 (GTP-C) Control Plane User Plane Evolved Packet Core (EPC) E-UTRAN MME HSS SGW-D SGW-C PGW-D PGW-C eNB

• The LTE/EPC has been designed to support only packet based

services.

• The EPC has a flat, all-IP architecture with separation of control plane

and data plane.

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LTE/EPC Drawbacks

• The initial attachments lead to a systematic establishment of the data

plane, even when there is no data traffic to be sent.

• The data plane establishment procedure is unaware of the session

type.

• The TEID values are locally allocated by each node  new TEID

values should be exchanged for each node relocation.

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LTE/EPC Drawbacks - 2

• SGW could be a bottle neck for possible user traffic congestion.
• Network equipment failure.

This PGW can be any where in all

• ver the world

Home PDN PGW SGW Internet (Ex. SIPTO above RAN) PGW IMS Semi-distributed GW (SGi) PGW This PGW could be allocated per county or region.

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OF-Based LTE/EPC Architecture

• Separation of control and

data plane from SGW.

• Replacing S1-MME and S11

interfaces with OF.

• SGW-D represents an

advanced OF switch that is able to en/decapsulate GTP packets.

• Unique TEID values per

session.

• eNB keeps the same radio

functions.

eNB eNB

OpenFlow Controller MME SGW-C S5 (GTP-C) OpenFlow protocol

UE

S 1 ( G T P

• U

) S5 (GTP-U) SGW-D PGW-D PGW-C

API

SGW-D SGW-D

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On-Demand Connectivity Service

• Resiliency
• Load Balancing

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Resiliency – 3GPP LTE/EPC case

• The 3GPP restoration procedure related to the SGW failure is not

transparent as it cuts off active sessions.

• Session re-establishment of impacted users may generate

significant amount of signaling.

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Resiliency – OF-Based LTE/EPC case

• Easily manage the active sessions during any SGW-D failures.
• Less packet loss.
• Centralized the TEID allocation function.

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Load Balancing – 3GPP LTE/EPC case

• SGW and PGW selection is performed by the MME.
• Offline weight factors in DNS server.
• Proactive load balancing.
• SGW could be a bottle neck for possible user traffic congestion.

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Load Balancing – OF-Based LTE/EPC case

• Real time load statistics.
• Free the overloaded SGW by moving some sessions seamlessly to

another SGW in the same domain.

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Implementation Challenges

• SGW control and data plane separation.
• Building mobile network based OF controller.
• The OF protocol should be extended to transport the UE-MME

exchanges transparently, e.g.

– Authentication messages – Mobility messages

• Shifting all control plane entities into cloud platform.

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Conclusion & Perspectives

• Proposal
• sal: OpenFlow-based control plane for LTE/EPC

architecture

– The SGW control plane is separated from the data forwarding plane – The SGW control plane is centralized and uses the OpenFlow protocol to remotely manage the SGW data forwarding plane  The proposed architecture ensures the on-demand connectivity service even in critic situation such as network equipment failure and overload situations

• Perspect

spectives: ives:

– Realize a testbed to validate the resiliency and load balancing aspects in our proposal – Try to make standardize the OF-based LTE/EPC in ONF working groups.

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