open epc tutorial

Fraunhofer FOKUSCompetence Center NGNI

Open EPC – A Short OverviewProf. Dr. Thomas Magedanz, TU Berlin/Fraunhofer FOKUSMarius Corici, Fraunhofer FOKUS Dragos Vingarzan, Fraunhofer FOKUS

Email: [email protected]: www.openepc.net


Full version of this tutorial is for IMS Workshop Track 4 Tutorial attendees only!

We are happy to provide customized onsite tutorials

Please contact:

Prof. Dr. Thomas [email protected]


Originally invented in the mobile world, the 3GPP IP Multimedia Subsystem (IMS) has become overthe last years the globally accepted common control platform for multimedia communication serviceprovision in Next Generation Networks (NGNs). In parallel the internet has matured towards aninnovative seamless multimedia communication, information and entertainment servicesenvironment, also referred to as Web 2.0.

Driven by the hype around the planed rollout of the Long term Evolution (LTE) wireless accessnetworks providing only packet transport capabilities, the notion of the next generation of fixed andmobile networks is emerging, which will be technically realized by the 3GPP Evolved Packet System(EPS). While LTE is forming as Evolved-UTRAN (E-UTRAN) the lower part of the EPS, a new IPconnectivity control platform has been defined for the upper part of the EPS to enable wirelessaccess networks diversity (including LTE, UMTS, WiMax, WLAN, etc) below different serviceplatforms, comprising both IMS-based and internet service architectures. This IP connectivity controlplatform is called Evolved Packet Core (EPC), previously known as Service Architecture Evolution(SAE), which has a lot of common principles with IMS, such as policy based QoS and Charging, userauthentication, handover support, etc. however limited to provide a seamless IP pipe to a serviceplatform. There is little doubt, that LTE, which will be initially provided in limited locations only andthus requires handover support with other existing wireless access network technologies, will dependon the proper operation of the EPC. In addition, the provisioning of seamless voice servicesrepresents a huge challenge within this environment. Moreover, a key question will be, what futurewireless broadband multimedia applications will drive the future mobile environment adoption.

Tutorial Abstract


This half day tutorial will introduce to the main concepts, architectures, standards, foraand related terminology in the field of Next Generation of Fixed and Mobile Networks.We will also briefly illustrate LTE capabilities, however the main focus will be in theintroduction of the all-IP control platform, namely the Evolved Packet Core. Here weexplain the key components, their capabilities and their main interactions. In addition,we will look at EPC application domains and in this context illustrate also to role of IMS.Finally we will introduce the brand new TU Berlin / FOKUS next generation of fixed andmobile networks toolkit enabling EPS testbed establishment, namely the OpenEPC andshow practical demonstrations in our Future Seamless Communication (FUSECO)Playground.

Attendees will gain a basic understanding of the future mobile networks capabilities,opportunities as well as technical and business challenges. Furthermore, they will learnhow IMS evolution relates to the EPC and how IMS can be utilized above the EPC forvoice and other multimedia services.

More information can be found at:

www.openepc.net

Tutorial Abstract (cont.)


Part 0: Motivation from NGN/IMS to Converged NGN/EPC

Part 1: Converged NGN Overview

Motivation for converged NGN: Mobile data increase vs. revenue decrease

Mobile Network Evolution

Key players in converged NGNs: NGMN Alliance, LTSI, and 3GPP

3GPP Evolved Packet System (EPS) Architecture Overview (LTE/E-UTRAN and EPC/SAE)

Part 2: Evolved Packet Core (EPC)

Long term Evolution (LTE) / Evolved UMTS Radio Access Network (E-UTRAN) Capabilities

Beyond LTE - EPC Motivation and Functional Overview (Security, QoS, Charging, mobility management, roaming, etc.)

Simplified EPC architecture over E-UTRAN (MME, SGW, PDNGW, HSS, PCRF)

Full EPC architecture above multiple access networks (3GPP and trusted/untrusted non-3GPP access networks)

Component interactions for registration, service access, mobility management, etc.

Detailed Agenda


Part 3: Mobile Services beyond the EPC: Voice, IMS and others

EPS application domains (Internet, IMS, and more)

The LTE challenge: Voice over LTE Options (comparison of SRVCC, CS over PS, CS Fallback, VoLGA)

Potential LTE/EPC rollout strategies

Part 4: Getting started with EPS: Introducing the new FOKUS OpenEPC testbed toolkit

Overview of the OpenEPC toolkit (components, capabilities, uses cases)

Practical demonstrations will show the possible usage of the EPC based on the FOKUS OpenEPC platform

Part 5: Summary and Q&A

Detailed Agenda (cont.)


About the Speakers Prof. Dr. Ing. habil Thomas Magedanz Thomas Magedanz (PhD) is professor in the electrical engineering and computer sciences faculty at the Technical University of Berlin, Germany, leading the chair for next generation networks (Architektur der Vermittlungsknoten –AV) supervising Master and PhD StudentsIn addition, he is director of the “NGNI” division at the Fraunhofer Institute FOKUS, which provides toolkits for NGN/IMS as well as Next Generation of Fixed and Mobile Networks /EPC test and development tools for global operators and vendors. Prof. Magedanz is one of the founding members of FOKUS (1988) and member of the management team.Furthermore he is principal consulant of Direct Link Consult e. V., a FOKUS Consulting spin off focussing on professional services, strategic studies and technology coaching.Prof. Magedanz is a globally recognised technology expert, based on his 18 years of practical experiences gained by managing various research and development projects in the various fields of today's convergence landscape (namely IT, telecoms, internet and entertainment).He acts often as invited tutorial speaker at major telecom conferences and workshops around the world.Prof. Magedanz is senior member of the IEEE, editorial board member of several journals, and the author of more than 200 technical papers/articles. He is the author of two books on IN standards and IN evolution.


About the Speakers (cont.)

Dipl.-Ing. Marius-Iulian Corici

Marius Corici received his Diploma in the Science of Systems and Computers –Computers Engineering from University “Politehnica” of Bucharest, Romania in 2005. He joined the Next Generation Network Infrastructures (NGNI) competence center of Fraunhofer FOKUS Institute in 2005. His research work includes multiple patent applications submitted in the area of IP network architectures and multiple publications in the area of Next Generation Networks (NGN) in collaboration with various industry partners.


About the Speakers (cont.)

Dipl.-Ing. Dragos Vingarzan

Dragos Vingarzan graduated as Dipl. Ing. at the “Politehnica” University of Bucharest, Romania in February 2005, the Computer Engineering program on base software, compilers and computer networks with a Diploma Thesis at Fraunhofer FOKUS which represented the first milestone of the Open IMS Playground. Since 2005, he continued his reseach activity at the same institute in the area of feasibility and performance studies on NGN/converged NGN architectures. Currently he is working on his PhD in the area of IMS core and Evolved Packet Core (EPC) networks, with special interests in prototyping, open source in telecommunications, performance benchmarking and interoperability. He is an active member of various IMS working groups.


Part 0: Motivation from NGN/IMS to Converged NGN/EPC


Motivation for Converged NGN: Mobile data increase vs. revenue decrease


Key players in Converged NGN: NGMN Alliance, LTSI, and 3GPP




Part 4: Getting started with EPS:

Introducing the new FOKUS OpenEPC testbed toolkit


Detailed Agenda


There is a lot of hype around Long-Term Evolution (LTE) and its commercial deployment

LTE roll out will require interworking with other existing and emerging wireless accessnetwork technologies

The 3GPP EPC is the new mobile core network suporting seamless mobility, QoS and charging across multiple IP access networks, incl. 3GPP and non-3GPP access

EPC shares a lot of concepts with IMS, e.g. overlay architecture concept, HSS, PCC, etc.

EPC maintains seamless IP connectivity and thus supports multiple application domains, including IMS and internet platforms

LTE provides IP services only, thus voice services, representing still the operator cash cow, are currently a potential show stopper

IMS provides a lot of needed capabilities in the voice domain and value added multimediaservices domain (e.g. RCS, IPTV, etc)

Early prototyping of next generation converged environments will be crucial to gain practical experiences

Similar to Open IMS Core for NGN, the OpenEPC toolkit is designed for converged NGN prototyping

Introduction


From IN to IMS to EPC: Pull intelligence out of the access nets

Open APIs OSA/Parlay/JAIN

IntelligentNetwork (IN)

IP Multimedia System (IMS)

TelecomWeb Service APIs

Parlay X

OMA PIOSE, PSA, GSMA ONE API

Web 2.0IN Services

based on SIBs

IN OverlayArchitecture

BearerNetworks

IT Impact on Telecoms

PSTNGSM

IP

Service DeliveryPlatform (SOA based)

IP NetworksNGN

DSLUMTS WLAN

Cable

Network Abstraction

Open Service APIs

Mobile IP NetworksConverged NGNs

LTE WIMAXWLAN

Evolved Packet Core (EPC)


IMS – Flexible & Controlled Service Provision on IP Networks• IMS does NOT standardize specific services, but enablers• IMS Core provides session control signaling based on SIP and AAA capabilities over Diameter• supports inherently multimedia over IP, VoIP, IM, presence (SIP)• IMS enables the flexibility in providing IP-based applications

Packet Core Network

SIP Server

Call ControlPresence ServerGroup Server

Content

Access Networks(WLAN, UMTS,

LTE, DSL)

Access Networks(WLAN, UMTS,

LTE, DSL)

Messaging Server

IMS Applications

IMS Core

Transport (RTP)


IMS is the common control platform within the NGN for manyApplication Domains

ConvergedNGN

(all-IP)

P/ISDN Emulation

VOIP, Videoconf., IM, FMC, Presence IPTV

P/ISDN EmulationSubsystem

IP MultimediaSubsystem

Streaming/IPTVSubystem

Reusable TransportSupport Systems

IMS supports all

PSTN

Web 2.0

What about other IP Applications

VoIP/Skype

Best effort

Internet


Evolution Path of 2G and 3G Technologies


Expected mobile Broadband Services

VoIP alternatives to expensive tariffs e.g., avoiding international roaming charges

Video/Music on demand while mobile

Multicast and broadcast service offerings

Interactive gaming (graphics, twitch games)

Downloaded applications

Larger, multi‐media, graphically intensive ones

High quality/definition audio/video services

Superior encoding options

Cloud computing functions and features (all user data is in the cloud)


From NGN to Converged NGN: an important step towards the Future Internet

FutureInternet

Evolution

Tele

com

mun

icat

ions

Internet

IMSMobile

Telecommunications

InternetRich Communications

& Media

NextGeneration

Network

NextGeneration

Mobile Network

FMC

PESIPTV

RCS

Fixed Telecommunications

P2PEvolved

Packet SystemPCC


Concept Reuse: From IMS for NGN to EPC for all-IP

OptionalIMS

InternetVCCPES

IPTVRCS

FixedMobile

IMS

VCC

Cable

Any A

pplication Platform

Any IP N

etwork

3GPP Release 6

3GPP Release 8

ICS MMtel

EvolvedPacket Core

2GGPRS

3GUMTS

4GLTE/WiMAX

WLAN2G GPRS

EPC can be seen as a more generalized „lightweight IMS“, Providng security, QoS, Charging, plus Mobility Management for any IP based protocol (HTTP, SIP, P2P, …)

Other Application Platforms

NGN

Next Generation of NGNsIPTVPES

PoCRCS

IMS

QoS, Charging, Security

TISPAN

PCC



is an evolution of the legacy GPRS architecture to improve performance and reducing costs

is the new, all-IP only, mobile core network introduced with LTE in 3GPP release 8

EPC is motivated by the fact that LTE is just one access network technology, and mobile applications have to interoperate with various access network technologies

LTE access and EPC overlay form together the Evolved Packet System (EPS),formerly known as System Architecture Evolution (SAE)

EPC is based on end-to-end IP only connectivity (no circuit switched connections!)

Clear delineation of control plane and data plane

Simplified architecture: flat IP architecture with a single core network

EPC is based entirely on IETF protocols

EPC allows the operator to realize a truly converged packet core supporting different wireless access technologies (3GPP and non-3GPP)

EPC maintains seamless mobility , QoS and unified charging and thus provides the foundation for seamless, consistent and optimized services provision independent of the access network type



The EPC is a multi-access core network based on the Internet Protocol (IP) one common packet core network for both

trusted networks including3GPP Access (LTE-E-UTRAN, UMTS-UTRAN, GPRS-GERAN)Non 3GPP Access (WIMAX, CDMA2000/HRPD)

and untrusted networks includingNon-3GPP Access (WLAN)

EPC provides connection to IP service domains

IMSInternet (or others, e.g. P2P etc.)

Important EPC functions include:

NAS and security (AAA) mobility and connectivity managementpolicy QoS control and charging (PCC)

IMS

EvolvedPacket Core

Internet

3GPPAccess

Non 3GPPAccess

trusted trusted / untrusted



Motivation for Converged NGN: Mobile data increase vs. revenue decrease


Key players in Converged NGN: NGMN Alliance, LTSI, and 3GPP







Detailed Agenda


Content and Apps over Bitpipes – Where is the Money??

• Network convergence based on IP has led to high competition

• Connectivity Services (QoS) versus Multimedia Services (Content)

IP – based Core Network(EPC)

GSMEDGEUMTS

CDMA

WirelinexDSL

LTEPOTS/ISDN

CommonApplicationsand Services

WLANWiMax


Mobile Network Architecture Evolution

Access

CircuitSwitched

PSTN

Access

CircuitSwitched

PSTN

PacketSwitched

IP

Access

CircuitSwitched

PSTN

PacketSwitched

IMS

IP

Access

PacketCore

IMS

IPPSTN

EPS (LTE/EPC)3G / IMS Evolution2G / GPRS / EDGE Evolution2G GSM

1991 2000 2004 2008


LTE/SAE/EPC – Towards a flat architecture

System Architecture Evolution (SAE) is the core network architecture of 3GPP's future LTE wireless communication standard.

SAE / EPC is the evolution of the GPRS Core Network, with some differences:

simplified architectureall IP Network onlysupport for higher throughput and lower latency radio access networks (RANs)support for multiple, heterogeneous RANs, including legacy systems as GPRS, but also non-3GPP systems (e.g. WiMAX)mobility between heterogeneous RANs, including legacy systems as GPRS, but also non-3GPP systems (e.g. WiMAX)


Who is Who in Next Generation Mobile Network context?

NGMN Alliance defines LTE/EPC Requirementshttp://www.ngmn.org

3GPP developes LTE/EPC Specificationshttp:// www.3gpp.org/Highlights/LTE/LTE.htmhttp://www.3gpp.org/Specification-Numbering

LTSI performs Proof of Concept / Interoperability Tests

http://www.lstiforum.org/file/news/Latest_LSTI_Results_Feb09_v1.pdf



3GPP Evolved Packet System = E-UTRAN + EPC


Evolved Packet System (EPS)

3GPP required a network architecture able to support the characteristics of E-UTRAN

The study point to generate such network architecture was called the “System Architecture Evolution” (SAE)

SAE objective was:

“to develop a framework for an evolution or migration of the 3GPP system to a higher-data-rate, lower-latency, packet-optimized system that supports, multiple RATs. The focus of this work is on the PS domain with the assumption that voice services are supported in this domain”

The result of that study is a new simplified All-IP architecture which fulfills the requirements of NMGN: the “Evolved Packet Core” (EPC)

The Evolved Packet System (EPS) is the term used to refer to the combination of EPC + E-UTRAN

The EPS is an IP network and uses the standard routing and transport mechanisms of the underlying IP network.


EPS Objectives

Provide higher data rates, lower latency, high level of security and enhanced QoS

Support a variety of different access systems (existing and future), ensuring mobility and service continuity between these access systems

Support access system selection based on a combination of operator policies, user preference and access network conditions

Realize improvements in basic system performance whilst maintaining the negotiated QoS across the whole system

Provide capabilities for co-existence with legacy systems and migration to the Evolved Packet System

See also 3GPP TS 22.278: Service requirements for the Evolved Packet System (EPS)


EPS Features

Support for IP traffic with QoS

Support for IP multicast

IP session control including mobility, session adaption to terminal capabilities, user preferences, subscriber priorities, network conditions etc.

Support for scalable multi-party sessions

Support simultaneous active Packet Data Network connections for the same User Equipment

Support for emergency calls

Support for multi-access and seamless mobility


EPS architecture (3GPP TS 23.401 and 3GPP TS 23.402)

Interconnection with UTRAN and GERAN through SGSN, MME and Serving Gw

In roaming scenarios PDN-Gw can be in the visited (local breakout) or in the home network (home routed)

Serving-Gw and PDN-Gw could be deployed together


LTE and the EPC in the near future

The deployment of E-UTRAN requires beside the eNodeBs the MME entity that handles mobility and NAS functions (authorization, security etc) and the IP Gateways

S-GW and P-GW may be combined in one box in the beginningThe full deployment of the EPC is not needed but it provides additional advantages to the operator

Non-3GPP networks may not be supported in the beginningNon-3GPP networks may not be supported in the beginning

The main disadvantage is that the EPC is a complex architecture with many interfaces and options which are not needed in all scenarios












Detailed Agenda


Evolved-UTRAN (eUTRAN)

Simplified Radio Access Network (RAN) architecture with less nodes

Evolved Node B (eNB) includes the functionsRadio Resource ManagementSelection of MMERouting user plane data to S-GwScheduling Measurement & Reporting

Source : 3GPP TS 36.300 Stage 2 Release 8 V8.8.0 (2009)


3G vs. LTE

Existing Paradigm(3G)

LTE

Voice Circuit Switched All VoIP

Broadband Services Best effort, limited and expensive

Real-time, interactive, low latency, true broadband QoS

Multisession Data Limited All about bearers, sessions, data flows

QoS No true e2e guarantees E2e guaranteed, strictly defined parameters, classification

Policy Management Not widely adopted True network wide policy control and management

Mobility Management Hidden in the RAN Visible and moved to the core












Detailed Agenda


EPS Functional Split between E-UTRAN and EPCTarget was the enhancement of Packet Switched technology to cope with higher data rates, lower latency, packet optimized system with support for multiple Radio Access Technologies

This lead to a simplified IP-based overlay architecture with distributed control

Functionality is divided between E-UTRAN (LTE radio access) and EPC (NAS and IP functionality)

Evolved Packet SystemEvolved UTRAN (E-UTRAN) Evolved Packet Core (EPC)

eNodeB (eNB)Inter Cell Radio Resource Management,

Radio Bearer Control, Connection Mobility Continuity, Radio Admission Control, Dynamic Resource Allocation

Mobility Management Entity (MME)NAS, Idle State control, Security, EPS

Bearer Control

S-GwMobility Anchoring

for intra-3GPP

PDN-GwIP address

allocation, Packet Filtering, inter 3GPP mobility

anchoring


EPS Mobility and Connectivity Concepts

The EPS Mobility Management (EMM) states describe the Mobility Management states that result from the mobility management procedures e.g. Attach and Tracking Area Update procedures.

The EPS Connection Management (ECM) states describe the signalling connectivity between the UE and the EPC.

In general, the ECM and EMM states are independent of each other.

Transition from EMM-REGISTERED to EMM-DEREGISTERED can occur regardless of the ECM state, e.g. by explicit detach signalling in ECM-CONNECTED or by implicit detach locally in the MME during ECM-IDLE.

However there are some relations, e.g. to transition from EMM-DEREGISTERED to EMM-REGISTERED the UE has to be in the ECM-CONNECTED state.


Evolved Packet Core Logical Functions

As defined in 3GPP TS 23.401 V9.2.0 the EPC supports the following logical functions:

Network Access Control Functions are covering network selection, authentication, authorization, admission control, lawful interception, and optionally policy control and charging (PCC)Packet Routeing and Transfer Functions, where the EPC is using the standard routeing and transport mechanisms of the underlying IP network.Mobility Management Functions are used to keep track of the current location of a UESecurity Functions comprise authentication of the UE by the network and service request validation, encryption, etc.Radio Resource Management Functions are concerned with the allocation and maintenance of radio communication paths, and are performed by the radio access network.Network Management Functions provide mechanisms to support O&M functions related to the Evolved Packet System.


Simplified EPC Architecture

HSS

E-UTRAN

Internet

Operator IP Services(e.g. IMS)

MME

eNB

GSM/PSTN/

UMTS

PDNGW

ServingGW

PCRF

Mobility Management

UserAuthentication

QoS basedPolicy & Charging

Voice InterworkingIP ServicesApplication Functions

ApplicationFunction

User Equipment Mobility Mgt

Policy & Charging

Authoriz & Authen

User PlaneHSS - Home Subscriber ServerMME - Mobility Management EntitySGW - Serving GatewayPDN GW - Packet Data Network GatewayPCRF - Policy and Charging Rules FunctioneNB – Evolved NodeB


EPC Key Elements

Home Subscriber Server (HSS)

Mobility Management Entity (MME)

Serving Gateway (Serving GW)

Packet Data Network Gateway (PDN GW)

Policy and Charging Rules Function (PCRF)

Application Function (AF)

User Equipment (UE)

Additional EPC Components (see later slides):3GPP AAA Server (for non-3GPP access networks)evolved Packet Data Gateway (ePGW) for untrusted access networks(WLAN)Trusted non-3GPP accesses (Access GW) for WiMax, etc.


Home Subscriber Server (HSS)

The Home Subscriber Server (HSS) is the main database of the EPC storing subscriber information.

This information includes static profiles, including identification information and dynamic information related to each Packet Data Network (PDN) context that the subscriber has established

The HSS has interfaces towards:MME3GPP AAA Server

HSSMME

AAA

Wx

S6a


Mobility Management Entity (MME)

The Mobility Management Entity (MME) is a component of the EPC which is only relevant for 3GPP accesses and key to E-UTRAN

MME is in charge of NAS (Non-Access-Stratum), Terminal Attachment and ECM modes, user authentication, S-Gw and PDN-Gw selection

MME does the mobility management and user plan bearer functions

It also performs mobility functions between E-UTRAN and GERAN/UTRAN

It has interfaces to

S-Gw E-UTRAN (eNodeB)HSS SGSN (for GERAN Interworking)

HSS

S11

S6a

ServingGWS1uS1c

MME

eNB

SGSN

S3


MME Functions

NAS signalling;

NAS signalling security;

Inter CN node signalling for mobility between 3GPP access networks (terminating S3);

UE Reachability in ECM-IDLE state (including control and execution of paging retransmission);

Tracking Area list management;

PDN GW and Serving GW selection;

MME selection for handovers with MME change;

SGSN selection for handovers to 2G or 3G 3GPP access networks;

Roaming (S6a towards home HSS);

Authentication & Authorization;

Bearer management functions including dedicated bearer establishment;

Lawful Interception of signalling traffic;

UE Reachability procedures.


EPC Gateways

Two logical Gateways exist:

Serving GW (S-GW)The Serving GW is the gateway which terminates the interface towards E-UTRAN.For each UE associated with the EPS, at a given point of time, there is a single Serving GW.

PDN GW (P-GW)The PDN GW is the gateway which terminates the SGi interface towards the PDN.If a UE is accessing multiple PDNs, there may be more than one PDN GW for that UE (however a mix of S5/S8 connectivity and Gn/Gp connectivity is not supported for that UE simultaneously)

NOTE: The PDN GW and the Serving GW may be implemented in one physical node or in separated physical nodes.


Packet Data Network Gateway (PDN-Gw)

The Packet Data Network Gateway (PDN-Gw) terminates the connection towards the IP service domains (IMS, Internet, or other)

The PDN-Gw is the mobility anchor between 3GPP and non-3GPP accesses

If PCC is deployed, it includes a PCEF (Policy and Charging Enforcement Function)

performs UE IP allocation, policy enforcement, packet filtering for each user, charging support, lawful interception and packet screening

There may be several PDN-Gw per user (for different IP services)

The PDN-Gw has interfaces to:

Serving-GwePDG3GPP AAA ServerTrusted non-3GPP access gatewayPCRF (if PCC is supported)Services (Application Functions)

PCRF

PDNGW

IMS /Internet

SGi

Rx

Gx

S5ServingGW

WiMax

AccessGW

AAA

S6b

WLAN

ePDG

S2a S2b


Policy and Charging Rules Function (PCRF)The Policy and Charging Rules Function (PCRF) performs QoS control, access control and charging related control in the EPC.

The PCRF is policy based and authorizes bearer and session establishment and modification.

Only one PCRF is assigned to all the connections of one subscriber

The PCRF has access to subscriber profiles stored in a database referred to the Subscriber Profile Repository (SPR) which is not currently standardized

The PCRF has interfaces to:

PCEF within the PDN-Gw, and Bearer Binding and Event Reporting Function (BBERFs) in GatewaysSubscriber Profile RepositoryApplication Function in the service layer

PCRF

PDN-Gw(PCEF)

IMS /Internet

SGi

Rx

GxS5S-Gw

(BBERF)

S2aS2b

HSS(SPR)

Gxx

ePDG(BBERF)

Access GW(BBERF)

Gxx

Sp


Roaming Architectures in the EPC

Two basic configurations are considered by 3GPP for roaming.

In both the HSS and the PCRF with access to subscriber profiles are located in the home network

Home routed: in this configuration the PDN-Gw is located in the home network (all data of the user is routed towards the home network), the services accessed by the user are also located in the home network (P-CSCF in home network in case of IMS)Local breakout: in this configuration the PDN-Gw is located in the visited network (no data packets of the user go through the home network) and the H-PCRF is connected to the V-PCRF to exchange the Policy and Charging Rules to be applied for the user

For non-3GPP accesses the 3GPP AAA Server included in the visited network is referred as 3GPP AAA Proxy as it retrieves data from the 3GPP AAA Server in the home network












Detailed Agenda


EPC Access Network Types

Note that the EPC provides controlled IP connectivity, in regard to

User authentication and authorizationQuality of Service and related ChargingMobility Management

The EPC allows multiple access networks to be connected in a controlled way to theeither

the internet orthe operator IP cloud (e.g. IMS or any intranet)

Trusted networks include

3GPP Access (LTE-E-UTRAN, UMTS-UTRAN, GPRS-GERAN)Non 3GPP Access (WLAN, WIMAX)

Untrusted networks include

Non-3GPP Access (WLAN)


3GPP AAA Server

The 3GPP Authentication, Authorization and Accounting (AAA) Server is a database function used for non-3GPP access networks

The 3GPP AAA Server stores information necessary to be used in the non-3GPP trusted network or in the ePDG for user authentication and authorization

The 3GPP AAA Server communicates with the HSS to retrieve user profiles and update their content

The 3GPP AAA Server has interfaces to:

The trusted non-3GPP access networkThe ePDGThe HSSThe PDN-GwAnother AAA Server (roaming)

AAA

WLAN

ePDG

Wx

SWa

STaS6b

HSS

PDNGW

WiMAX

AccessGW


Trusted non-3GPP Gateways

Trusted non-3GPP accesses include:

HRPD (High Rate Packet Data from 3GPP2)WiMAX (from WiMAX Forum)

The HRPD Gw or the ASN-Gw perform mobility functions (if PMIP they include a PMIP MAG) and policy (QoS and charging) control (if PCC is deployed they include a BBERF)

They are the non-3GPP equivalent from the Serving-Gw

They have interfaces to the following

PDN-GwAAA ServerPCRF (if PCC is supported)HRPD (GW) to MME for HO with optimizations

PCRFPDNGW

ServingGW

WiMax

AccessGW

AAA

WLAN

ePDG

S2a

Gxx


evolved Packet Data Gateway (ePDG)

The evolved Packet Data Gateway (ePDG) is the gateway towards the non-3GPP untrusted access networks

The ePDG performs important security functionality tunnel authentication and authorization, IPSec encapsulation/de-capsulation of packets

If PMIP is used the ePDG includes the functionality of the MAG

If PCC is deployed the ePDG may include the BBERF

The ePDG has interfaces to:

PDN-Gw3GPP AAA ServerPCRF, if PCC is supported

PCRF

PDNGW

ServingGW

WiMax

AccessGW

AAA

WLAN

ePDG

S2b

Gxx


Access Network Discovery and Selection Function

The Access Network Discovery and Selection Function (ANDSF) is a new EPC element in Release 8, which performs data management and control functionality to assist the UE on the selection of the optimal access network in an heterogeneous scenario

The ANDSF exchanges discovery information and Inter-System mobility policies with the UE

The specific functionality of this component and its interfaces is being standardized currently in Release 9

The ANDSF has (for now) interfaces to:S14 to UE (OMA Device Management over HTTP over TLS over TCP)

ANDSFS14


Protocols used in EPC

Network Layer Protocols

IPMobile IP (MIP) and variationsProxy Mobile IP over IPv6 (PMIPv6)GTP

Transport Layer Protocols

Strem Control Transport Protocol (SCTP)TCP/UDP

Application Level Protocols

OMA Device Management (DM) over HTTP or UDP or otherDiameterS1-AP


Full EPC Architecture Reference Points & Protocols

HSS

PCRF

E-UTRAN

PDNGW

AAA

TrustedNon-3GPP Access

WLAN

AccessGW

WLAN

ePDG

GERAN

UTRAN

SGSN

Internet

Operator IP Services

(e.g. IMS)

Trusted3GPP Access

S11

SGi

S6a Wx

Rx+

GxS5/S8Serving

GW

S3

S4

S1uS1MMESWa

S2b

Gxx

MME

STa

S6b

S2a

Gxx Gxx

Trusted 3GPP AccessUntustednon-3GPP Access

Mobility Mgt

Policy & Charging

Authoriz & Authent.

User PlaneGTP U

PMIP

S1AP

PMIP

GTP

PM

IP

DIA

M

DIAM

DIA

M

DIAM

DIA

M

DIAM

DIA

M

MIP

MIP

GTP CGTP C

eNB

S10GTP C

GTP

X2












Detailed Agenda


AAA in EPC

Authorization Authentication and Accounting (AAA) in the EPC is performed by the HSS, MME and 3GPP AAA Server and partially by the ePDG and trusted non-3GPP access network

Authentication is done using the AKA procedure for 3GPP and the EAP-AKA for non-3GPP access networks

The HSS stores the secret keys and sends a derivation of them (authentication vectors) to the MME or 3GPP AAA Server to perform the AKA procedures and derivate the session keys

The ePDG is involved in the security tunnels authorization and authentication between the UE and the EPC through the non-3GPP untrusted network


QoS in the EPS

The “bearer” is a central element of the EPS QoS concept and is the level of granularity for bearer-level QoS control.

The network-initiated QoS control paradigm specified in EPS is a set of signaling procedures for managing bearers and controlling their QoS assigned by the network.

The EPS QoS concept is class-based, where each bearer is assigned one and only one QoS class Identifier (QCI) by the network.

An EPS bearer uniquely identifies packet flows that receive a common QoS treatment between the terminal and the gateway.

A packet flow is defined by a five-tuple-based packet filter, that is, the packet filters in the terminal (for uplink traffic) and the gateway (for downlink traffic) determine the packet flows associated with an EPS bearer.

The five-tuple contains source and destination IP address, source and destinationport number, and protocol ID


Default vs. Dedicated EPS Bearers

An EPS bearer is either a default or a dedicated bearer

The default bearer is the bearer that is set up when the terminal attaches to the network

One default bearer exists per terminal IP address, and it is kept for as long as the terminal retains that IP address.The default bearer provides the basic connectivity. The QoS level of the default bearer is assigned based on subscription data.


QoS and Charging in EPC

QoS control and Charging control is done in the EPC following the architecture of the Policy and Charging Control (PCC) which has been available since 3GPP Release 7

The PCC (Release 7) comprises the

Subscriber Profile Repository (SPR), Policy and Charging Rules Function (PCRF) , and Policy and Charging Enforcement Function (PCEF)

The deployment of the PCC architecture is optional for the EPC as the operator may decide to perform profile based QoS control (static)

In Release 8 the PCC also includes the Bearer Binding and Event Reporting Function (BBERF) and two modes of operation of the PCRF for roaming scenarios Home-PCRF and Visited-PCRF with an interface (S9) between them

The PCRF keeps control of the bearers and sessions established by the users and the treatment the network gives to them

The QoS control in the PCC level is independent of the access network used as a standard set of parameters is used which are later translated to specific access parameters in the gateways


QoS and Charging in EPC (2)

The Policy and Charging Enforcement Function (PCEF) is co-located in the PDN-Gw and does firewall control and QoS enforcement, credit management and reporting

The Bearer Binding and Event Reporting Function (BBERF) is located in a peripheral gateway and does QoS control and event reporting

Two modes of operation exist:

PULL: the BBERF and PCEF inform thePCRF upon bearer level establishment,modification or releasePUSH: the Application Function informsthe PCRF upon new session establishment,modification or release

The Bearer Binding and Session Binding mechanisms perform the adequate matching


Mobility Management in EPC

Mobility Management refers to the need of the UE to change the point of attachment to the EPC as it moves

In the EPC mobility management involves the preservation of IP address of the UE during an attachment point modification

Tunnels are established between an anchor point and the attachment point

A signaling protocol is used for tunnel control

On change of attachment a new tunnel is established and the anchor forwards packets through it


Intra 3GPP Mobility

Mobility between E-UTRAN, UTRAN and GERAN is anchored in the Serving-Gw

GPRS Tunneling Protocol (GTP) is used for intra-3GPP mobility, as it was used in UTRAN

GTP-C controls tunnel establishment, modification and releaseGTP-U encapsulates user-plane packets (tunnel)

Intra E-UTRAN mobility is done by eNodeBs involved. Target eNodeB informs MME of path switch after completion (if no MME relocation is required)

UTRAN/GERAN mobility involves communication between SGSN and MME during the handover


Heterogeneous Mobility

Mobility between 3GPP accesses and non-3GPP accesses uses standard IETF protocols

Signaling is done using protocols of the family of Mobile IP (MIP) for the signaling

Tunneling is done using Generic Routing Encapsulation (GRE) tunnels

Two schemes supportedNetwork Based Mobility

Based on Proxy Mobile IP Protocol (PMIP) where the UE does not need any extensions as the mobility is fully handled by the networkHost Based Mobility

Based on Mobile IP (MIP) Foreign Agent (FA) which requires software extensions in the UE

Based on Dual Stack MIP (DSMIP) for the case of heterogeneous IPv4/IPv6 networks


Scalability by Selection Functions – Self Organizing Networks (SON)

Each EPC entity is selected from a poolThe eNodeB is selected by the UE upon attachmentThe eNodeB selects the MMEThe MME selects the S-GWThe PDN GW is selected by the S-GW, ePDG etc.The UE selects the ePDGThe PDN GW selects the PCRF through Diameter Routing Agent (DRA)

Reselection as part of the management and mobility proceduresThe eNodeB, the MME, the S-GW, the PDN GW may be changed during operationPCRF and HSS are the only entities to which the UE is remotely bound during full operation

Allows easy integration / maintenance of network entities


EPC Capabilities = Seamless IP Connectivity

The EPC allows multiple access networks to be connected in a controlled way(secure, QoS, seamless) to either

the operator IP cloud (e.g. IMS or any intranet)the internet or others

Note that the EPC provides controlled IP connectivity, in regard to

User authentication and authorizationQuality of Service and related ChargingMobility Management

E-UTRAN

User EquipmentMay be connected to

several IP serviceDomain in parallel

EPCUTRAN

WiMAX

WLAN

IMS

Internet

Packet GW

Packet GW


EPC connects to IP Service Domains

The EPC provides connection to IP Service DomainsIMSInternetother (P2P etc.)

IMS

EvolvedPacket Core

Internet


Simplified EPC Architecture with IMS

HSS

E-UTRAN

S1

MME

eNB

PSTN

PDNGW

ServingGW

PCRF

IMS

P/I/S-CSCF

MGW ASASAS

IMS Services:ICS, MMTel, VCCVoice

QoS basedPolicy & Charging

UserAuthentication

Mobility Management

ICS: IMS Centralised ServicesMMTel: Multimedia TelefonyVCC: Voice Call Continuity


IMS Standards Evolution in regard to Access Network Evolution

IMS developed as part of 3GPP Release 5 as an application development environment based on IN/CAMEL and VoIP (IETF) concepts and protocols

Encourage new applications on top of 3G networksGreater operator policing than native SIP/SDPHome control allowing service customization

IMS retargeted in Release 7 for telephony replacement

Standardized multimedia suite developed (ICS, MMTel, VCC)Optimizations for QoS and Charging (PCC)Access independence

Common IMS specified in Release 8

Extension of Session Mobility supportIntegration of IMS variants and requirements from 3GPP2, TISPAN, and Cablelabs

MMTel, ICS, VCCPCC


IMS VoIP in EPC Architecture

HSS

E-UTRAN

IMS

S1

MME

eNB

GSM/PSTN/UMTS

PDNGW

ServingGW

PCRFP/I/S-CSCF

MGW ASASAS

VoIP ???

IMS MMTel + ICS

Note that VoIP in

the initial LTE

deployments is

unrealistic due to

limited initial LTE

coverage


Voice in LTE Options

LTE being packet only does not include a final solution for providing voice calls over the new network in the near future ;-(

Several solutions have been proposed and are under discussion:Single Radio Voice Call Continuity (SR-VCC): IMS ICS based call control and handover from LTE to 2G/3G via dedicated IMS AS (SCC AS)

IMS Centralized Services (ICS): IMS based solution evolved from older device centric Voice Call Continuity (VCC) and MMtel, MSC has to host IMS Client and MGw

MMTel: IMS based solution for providing PSTN supplementary services for VoIP plus multimedia session handling capabilities (RCS)Circuit Switched Fallback (CSFB): all incoming/outgoing voice calls are immediately handed over from LTE to 2G/3G before call setupCS over EPS: MCS replacement by special EPS AS (still a study point)Voice over LTE using Generic Access Network (VoLGA): EPS behaves like an RNC or a BSC (CS over IP re-using UMA) no MSC changes!

IMS


Voice over LTE Comparison

Approach

3G

PP

IMS

Additional ComponentModified

Components Main AdvantageMain

DisadvantageName Function

SR-VCC X X VCC AS

Anchor sessions in the IMS

domainMME,MSC,UE

VCC is an existing method, which has been improved for

Single Radio

RequiresIMS and

improvements in

MSC and MME

ICS X X SCC AS

Anchor and control sessions MSC,UE

Handover to 2G, canbe used by GSM mobiles as well, Supplementary

servicesCompatible with SR-

VCC

Requires IMS and complex

AS

MMTel X X UE

Only defines aninteroperable way to

handle speech sessions for IMS

IMScentric solution


Voice over LTE Comparison II

Approach

3G

PP

IMS

Additional Component ModifiedComponents Main Advantage

Main Disadvant

ageName Function

CSFB X MSC,MME,UE

No support for voicein E-UTRAN under

the supposition that it coexists with GERAN/UTRAN

Additionaldelay,

suboptimal option

CS overEPS X eMSC

MSC with new interface towards UE and MMEAS behavior towards PCRF and PDN-Gw

UECS signaling

encapsulated over IP towards new eMSC

Not yet completed. Not PS native

solution.

VOLGAVANC

BSC or RNC behavior (A or Iu mode) towards CS, AS behavior towards PS

UE

CS signaling encapsulated over IP

towards VANC. Follows the structure of already existing

GAN specifications of 3GPP

Not yet 3GPP

solution.Not PS native

solutionHOSF Handover target

selection


LTE/EPC Roadmap

In 3GPP

The Evolved Packet Core standardization has been completed with the LTE standardization in Release 8 (end 2008)Some features and issues left to Release 9 and Release 10

Operators committed to deploy LTE/E-UTRAN:

USA : Verizon Wireless (2010), MetroPCS Wireless and US CellularNTT-Docomo and KDDI in Japan (2010)T-Mobile, Vodafone, Telefonica, TeliaSonera, Tele2, Telenor…China Mobile, KT and SK Telecom in Asia







Overview of the OpenEPC toolkit (components, capabilities, uses cases)

Practical demonstrations will show the possible usage of the EPC based on the FOKUS OpenEPC platform




From Open IMS to Open EPC: an important step towards the FI

FutureInternet

Evolution

Tele

com

mun

icat

ions

Internet

Fixed Telecommunications

IMS

P2P

Mobile Telecommunications

EPC

InternetRich Communications

& Media

NextGeneration

Network

NextGeneration

MobileNetwork

FMC

PESIPTV

RCS


“Open IMS Core made the NGN world possible. OpenEPC will bring about the future mobile application sphere”

From the Open IMS Core to an Open EPC platform

www.openepc.net


In NGN/Converged NGNs multi access network support (fixed, mobile, cable) and multi application domain support (OTT, P2P, IMS, etc.) will become key for multimedia service delivery

Based on the Open IMS Core success, FOKUS is developing a NON-OPEN SOURCE EPC platform, enabling academia and industry to

integrate various network technologies and integrate various application platforms

into a single local testbed, lowering development costs

This platform can be used to perform R&D in the fields of

QoS, Mobility, Security, ManagementOpen EPC is conformant to 3GPP specifications (Rel 8)

High performantAdaptable to different deploymentsExtensible to specific research needsConfigurable

What is the FOKUS OpenEPC platform


OpenEPC includes the main functionalities of 3GPP's Evolved Packet Core

The principles of standards conformance, configurability and extensibility have been respected in the overall architecture and the specific components

In its first release a subset of functionalities and features is available as depicted below

OpenEPC Architecture


OpenEPC has been successfully tested for IPv4 and IPv6. Heterogeneous IPv4/IPv6 scenarios will be added in the future.

OpenEPC includes different components for the network entities as well as a demonstrative client module based on myMONSTER client framework and the myMONSTER Telco Communicator Suite (TCS).

All software components of OpenEPC except myMONSTER client modules have been developed in C based on a high modular and configurable software framework. This framework allows for easy configuration of components, selecting from the library of functionalities available. With this approach, OpenEPC supports customized components which can include or exclude some functionality or interfaces.

For instance, a deployment could include a S-Gw which performs BBERF functionality of the Policy and Charging Control architecture or a PCRF which does not include S9 interface for roaming scenarios. Such customizations are supported by simply modifying the XML configuration file and adding or deleting the lines for such modules.

The components that require dynamic configuration or provisioning of parameters (like PCRF, HSS or ANDSF) offer a web-based front-end. In complete configurations a common front-end is used to configure all components.

OpenEPC Architecture (cont.)


OpenEPC HSS provides storage and provisioning facilities for subscriber profile as defined in the EPC technical specification. It also performs the non-standard Subscriber Profile Repository (SPR) functionality described in the Policy and Charging Control (PCC) architecture documentation. For this, it offers an implementation of the not yet standard interface Sp. This interface permits the support of personalization through profiles.

The definition of the OpenEPC interface has been developed based on the Open IMS Core Sh interface used between HSS and an IMS Application Server with the addition of some specific Attribute Value Pairs (AVPs). Concretely, the Data-Reference AVP has been extended to include parameters which are fetched from HSS and are used for policy control and for access network discovery and selection.

Interfaces provided:

Sp with ANDSF or PCRFIMS Interfaces: Cx, Dx, Sh

The S6a, S6b and S6c will be added in a following release of OpenEPC.

OpenEPC Home Subscriber System (HSS)


The Policy and Charging Rules Function (PCRF) implementation of the OpenEPC is an evolution of the PCRF included in the FOKUS PoCCA component set which was released in January 2008. This new PCRF aligns with the Release 8 requirements on interfaces (Gxx and S9 new interfaces) and functionality.

The PCRF permits the application function (e.g. P-CSCF, DPI system etc.) to request resources and priority treatment from OpenEPC, through Rx interface, to consult the subscriber profile downloaded from the HSS/SPR via Sp interface and to make the policy decision to be enforced in network gateways using Gx and Gxx interfaces.

The PCRF also subscribes to modifications in subscriber profile that may affect the policy decision or require it to be modified.

Towards gateways the PCRF implements Gx and Gxx interfaces to the PCEF deployed in a PDN-Gw and to BBERF of an S-Gw or an ePDG.

The behavior of PCRF is controlled through XML described policies which can be provisioned from a GUI dynamically as well as stored in a file. The policy description language complies with OMA Policy Expression Language extending it to support the necessary tags for the functionality of PCRF.

OpenEPC PCRF


The development of interfaces of PCRF has been done as loadable modules; therefore a specific deployment of OpenEPC PCRF is not forced to include all of them.

The OpenEPC PCRF is suitable of performing TISPAN Resource and Admission Control Subsystem (RACS), Service based Policy Decision Function (SPDF). It provides the Gqprima interface to application function and it is planned that it will be extended for next releases to support the Ia and Rq interfaces of RACS. In a further extension modules to include the Re interface and the e4 interface can be deployed to complete the overall RACS functions.

PCRF Interfaces:

Rx with Application FunctionGqprima (ETSI) with Application FunctionGx with PCEF in PDN-GwGxx with BBERF in S-Gw or ePDGSp with SPR/HSSS9 with another PCRF

Charging functionality is not currently part of the OpenEPC PCRF and it will be supported in a future release of OpenEPC.

OpenEPC PCRF (cont.)


OpenEPC PDN-Gw includes a PMIPv4 or PMIPv6 stack configured as a Local Mobility Anchor (LMA). It allocates IP addresses from a provisioned pool. It also supports Policy and Charging Enforcement Function (PCEF) module for Policy and Charging Control.

PCEF module permits to allocate default QoS values upon attachment of a new subscriber to the PDN and service specific rules when a user accesses a service. The enforcement of these rules is done through standard Linux network tools accessed through shell scripts, and therefore fully configurable.

Current interfaces offered:

PMIP based S5/S8 with Serving-GwSGi with services domainS2b with the ePDGS2c with the UEGx from co-located PCEF to PCRF

In future releases, there will be support for other mobility protocols specified in the 3GPP EPC: Dual Stack Mobile IP (DSMIP), Mobile IP Foreign Agent Care of Address (MIP FACoA) and GRPS Tunneling Protocol (GTP).

Support for S6a interface to AAA server will also be supported in the next releases.

OpenEPC PDN Gateway (PDN-Gw)


OpenEPC Serving-Gw includes a PMIPv4 or PMIPv6 Mobility Access Gateway (MAG) function. It also includes a module integrating with a standard DHCP server. The attachment of the user to EPC is detected in network level through the request of IP address and configuration parameters over DHCP.

The OpenEPC Serving-Gw can also include a Bearer Binding and Event Reporting Function (BBERF) for policy control. This function permits to request QoS and priority parameters for IP flows associated with a subscriber. Resulting QoS rules are enforced in the gateway by the standard Linux network tools (e.g. iptables, traffic classes etc.) through shell scripts that permit customization.

Current interfaces offered are:

PMIP based S5/S8 to PDN-GwGxx from co-located BBERF to PCRF

Support for GPRS Tunnelling Protocol (GTP) will be included in subsequent releases of OpenEPC

OpenEPC Serving Gateway (Serving-Gw)


OpenEPC ePDG includes a PMIPv4 or PMIPv6 Mobility Access Gateway (MAG) function. It includes a module integrating with a standard DHCP server. Attachment of the user to EPC is detected in network level through the request of IP address and configuration parameters over DHCP.

OpenEPC ePDG can also include a Bearer Binding and Event Reporting Function (BBERF) for policy control. This function permits to request QoS and priority parameters for IP flows associated with a subscriber. Resulting QoS rules are enforced in the gateway by the standard Linux network tools (iptables, traffic classes etc.) through shell scripts that permit customization.

Current interfaces offered:

Gxx of collocated BBERF with PCRFS2b between ePDG and PDN-Gw

Future releases will support SWu interface and IPSec requests as an attachment trigger as well as SWm interface to AAA Server for authentication.

OpenEPC evolved Packet Data Network Gateway (ePDG)


Access Network Discovery and Selection Function (ANDSF) is a new Release 8 feature of 3GPP that has not yet been fully standardized. At this point, the OpenEPC ANDSF includes several non-standard functionalities necessary to provide a demonstrative usage of its functionality.

On its current status the description of ANDSF is included in 3GPP TS 24.302

ANDSF has a S14 interface with User Equipment (UE) used to provide information on access networks available in the vicinity of the subscriber and information on operator’s preference on these access networks.

This information is provided in an XML format specified by 3GPP under TS 24.312.

The OpenEPC ANDSF includes an interface with the HSS based on the Sh interface between the AS and HSS which provides personalization based on subscribers’ profiles.

The interfaces offered by the OpenEPC ANDSF are:

Sp to HSS

S14 to UE

A GUI is included for configuring the behavior of the ANDSF for demonstration of different Always Best Connected (ABC) scenarios.

In further releases the ANDSF will include other interfaces and features as soon as they are standardized.

OpenEPC Access Network Discovery and Selection Function


OpenEPC includes an EPC ready client.

It is the only non C component of OpenEPC. It has been done as a module of the myMONSTER Telco Communicator Suite (TCS)

www.mymonster.org

The OpenEPC module provides S14 interface to the ANDSF and a mobility manager that calls external scripts to switch on interfaces, trigger attachments, detachments and handovers.

Besides that, myMONSTER TCS offers the possibility of accessing IMS/SIP or Web-based services therefore permits trying out EPC functionalities in different configurations.

OPENEPC enabled Client – MyMonster TCS


Mobility Support

Policy and Charging Control

Subscriber Handling and Databases

Interconnection with Access Networks

Interconnection with Applications and Services

Security Support

OpenEPC Capabilities


Mobility is one of the main features of EPC as it provides a converged core in which several wireless access networks are connected. In EPC a subscriber can hand over from one access network and technology to another preserving its IP address and IP connectivity. Several technologies are supported for this, from the GPRS Tunnelling Protocol (GTP) used in 3GPP access networks up to three different Mobile IP (MIP) variants.

For the realization of the Always-Best-Connected scenario in a converged network, EPC includes the Access Network Discovery and Selection Function (ANDSF) which exchanges information of the available and preferred access networks with the User Equipment (UE). This function is a Release 8 addition which still is being completed in Release 9 standardization work.

OpenEPC includes a Proxy-MIP (PMIP) stack integrated in access gateways (S-Gw, ePDG) and PDN-Gw. PMIP is the newest MIP variant standardized by IETF and used in EPC with the necessary additions of 3GPP (GRE tunneling with keying support, Binding Revocations etc.).

IP mobility between different access technologies i.e. vertical handovers is provided using PMIP following the concept of make-before-break. The subscriber creates attaches to the new access network before detaching from the previous one, creating a new context with the same IP address to which traffic is forwarded seamlessly.

Mobility Support


PoCCA version 2.0 is the Release 8 compliant prototype of the Policy and Charging Control (PCC) architecture defined by 3GPP for EPC. Even though the PCC architecture was already present in Release 7, Release 8 has introduced major changes to it, in order to cope with the requirements of EPC. These new features include: Introduction of the Bearer Binding and Event Reporting Function (BBERF) which is included in access network gateways

Inclusion of PCEF in the Packet Data Network Gateway (PDN-Gw) instead of GGSN or ePDG as described in Release 7

Split of the Policy and Charging Rules Function (PCRF) functionality between Home-PCRF and Visited-PCRF for support of more flexible roaming scenarios

Inclusion in all scenarios of Subscriber Profile Repository (SPR) for profile storage and its interface to PCRF (Sp) which is still not standardized.

PoCCAv2.0 includes a Release 8 compliant PCRF, PCEF and BBERF as well as an implementation of the Sp interface towards the HSS to access subscriber profile used in policy decisions. The BBERF and PCEF are integrated as part of the OpenEPC gateways and the PCRF is a standalone component of OpenEPC.

PoCCAv2.0 permits policy based QoS control relaying in Linux Gateway functionality (Firewalling, Packet Marking etc.) and co-location with OpenEPC mobility and address allocation solutions for triggering of network events (attachment, detachments, modifications, handovers etc.).

PCC


EPC makes use of the Home Subscriber Server (HSS) already defined in the IP Multimedia Subsystem (IMS), as main subscriber information repository. The HSS in Release 8 includes new interfaces to EPC elements and new stored parameters necessary for EPC functionality.

The HSS in OpenEPC acts also as a Subscribers Profile Repository (SPR) defined in the Policy and Charging Control (PCC) architecture, permitting access to subscribers’ profile both to PCRF and ANDSF based on an extension of Sh interface (interface between HSS and IMS Application Server) although 3GPP standards only include requirements for this interfaces and do not yet include any specification of how these are realized.

For authentication and access authorization functionality for the non-3GPP accesses, the 3GPP AAA Server already described in previous 3GPP releases is being integrated in EPC. The 3GPP AAA Server performs two roles: Server and Proxy in roaming scenarios.

An implementation of the 3GPP AAA Server will be included in a next release of OpenEPC.

Subscriber Handling and Databases


Being a mobile core network EPC is connected to various access networks. This is done through peripheral gateways: S-Gw in 3GPP technologies, a HRPD-Gw in HRPD or ASN-Gw in WiMAX or ePDG for other non-3GPP technologies. All these functions, referred generic as Access Network Gateways (ANGw), constitute the interface between the access networks and EPC and perform IP address allocation, mobility functions, QoS enforcement functions etc. They permit the triggering of EPC procedures and enforcement of EPC decisions.

In OpenEPC these functions are implemented as Linux software components that support the load of different modules (a PMIP MAG, a BBERF, a DHCP server/proxy function, a Linux Gateway firewalling and Diffserv packet marking function etc.,) and interact with each other.

OpenEPC provides the ANGw to interact with current 3G networks, Wi-Fi networks or any other access network that provides IP connectivity, independent of physical or MAC procedures.

Interconnection with Access Networks


OpenEPC provides interconnection between the Applications and Services layer and the network layer. EPC provides IP connectivity far beyond the concept of an IP pipe by supporting extended features like QoS, resource reservation, prioritization and information on events occurring in the access network (e.g. the mobile user lost the bearer, the mobile user changed access technology etc.), which are needed in multiple converged fixed and mobile networks scenarios.

These features are realized through two interfaces. The SGi interface is the IP interface from PDN-Gw to applications layer through which user data is sent. The Rx interface from PCRF to application layer is the signaling interface based on Diameter that allows application layer to request special treatment to certain service flows and to get notifications upon events occurring in the access network.

OpenEPC provides both interfaces and example functionality to demonstrate the interconnection to both Internet and the 3GPP IP Multimedia Subsystem (IMS).

Interconnection with Applications and Services


Internet

OpenEPC provides Rx and SGi interfaces towards Internet or any other Service Delivery Platform.For demonstrative applications an HTTP Proxy/Transcoder or DPI system with support for Rx interface are used.

IMS

The combination of OpenIMSCore and OpenEPC provides a complete testing environment for 3GPP converged NGN technologies. Interconnection of IMS is done through Rx interface for signaling and SGi interface for data.Rx interface between the P-CSCF and PCRF supports the QoS and resource allocation for IMS sessions. This functionality is included in the PoCCA v2.0 architecture. Also the P-CSCF is notified, upon subscription, of the network connection status of the subscriber. This feature is referred as “notification of IMS signaling path status” in the 3GPP specifications. The P-CSCF can also indicate that an IP flow is being used for IMS signaling so that it can be treated with preference within EPC.Together with OpenEPC, IMS can realize its potential to provide an adequate platform for converged NGN scenarios in which QoS, mobility and security schemes are aligned between service layer and connectivity layer.

Interconnection with Applications and Services (cont.)


OpenEPC Use Cases

Operators are using OpenEPC to prepare for the upcoming all-IP NGN world and have an open and vendor independent test-bed infrastructure.

Manufacturers of individual EPC components are using OpenEPC to test their products in concert with a standards based converged NGN environment.

Manufacturers of full EPC platforms are using OpenEPC for practical research on new concepts and protocols in an easier to maintain platform.

Application developers are using OpenEPC to certify that their applications work in converged NGNs and take advantage of the functional capabilities offered by EPC to the applications domains.

Research institutions and universities are using OpenEPC for practical all-IP NGN research , including usage of OpenEPC as black box for applications prototyping, or extending individual or multiple EPC components and/or developing new EPC components and protocols to provide new capabilities for integrating new networks or enabling new applications.


Handovers in Heterogeneous Networks

Support for Always best connected (ABC)

Subscriber profile based personalization

QoS provisioning

Access to IMS services throough OpenEPC

Access to Internet through OpenEPC

OpenEPC Usage Scenarios


OpenEPC can connect to different types of access networks providing IP connectivity and handover between them. From the various mobility protocols supported by EPC, OpenEPC currently integrates Proxy Mobile IP (PMIP). PMIP is a genuine network based mobility protocol which does not require a mobility stack in the User Equipment (UE) by transferring the mobility functionality to the network gateways.

Within the Fraunhofer FOKUS laboratories in Berlin Wi-Fi access and the public commercial UMTS network are available.

To emulate an operator controlled access in the public commercial UMTS network tunneling to OpenEPC Serving Gateway (S-Gw) is performed and over this tunnel a virtual IP address used in the lab is allocated.

Over Wi-Fi, no emulation is needed as the ePDG is connected physically with a Wi-Fi access point over which the address allocation is done.

These two gateways are connected with the PDN-Gw using PMIP Protocol (either IPv4 or IPv6 depending on the configuration) to get the IP address and establish IP tunnels for the traffic from and towards the user.

After attachment to an access network, the IP address is allocated and a is tunnel established. When the user attaches to the other access network the same IP address is preserved and the traffic is redirected to the new tunnel, providing seamless mobility.

The myMONSTER TCS module for EPC allows selecting which access network the user is connected to and modify this during a session, triggering new attachment and receiving packets over the old network until the new one is ready.

Handovers in Heterogeneous Networks


Personalization is a key feature of the future next generation of fixed and mobile networks that permits discrimination of users and mobile devices based on their different requirements.

3GPP standards define the HSS as the main profile repository in EPC. The interfaces of the HSS include the interfaces to the MME (S6a), the SGSN (S6d) and the AAA Server (SWx). They are used for authentication and updates of the context information when a subscriber attaches or modifies its attachment characteristics.

The standardized EPC subscriber profile includes some information tokens which are used to offer personalization to subscribers like access restriction or QoS profiles.

The Policy and Charging Control (PCC) specifications consider another entity: the Subscriber Profile Repository (SPR), which contains policy data used by the PCRF as input for decisions on the service authorization and QoS control. The relation between the SPR and the HSS is not part of 3GPP Release 8 or Release 9. The Sp interface between the PCRF and the SPR has not yet been described by 3GPP.

OpenEPC uses the HSS and the standard profile data as SPR. The Sp interface has been implemented based on the Sh interface (from HSS to IMS Application Server) defining new values for the contained AVPs (Attribute Value Pairs) e.g. Data-Reference AVP and re-using the AVPs of the interfaces S6a, S6d and SWx to carry the data stored in the subscribers’ profile. The Sh interface was already implemented in the Open IMS Core and provides the needed operations: profile fetching and updating, subscriptions for modification, notifications pushing.

Subscriber profile based personalization


The Sp interface has been re-used as well in the ANDSF to provide personalization parameters for the access network reselection decisions. The ANDSF upon attachment of a subscriber downloads the profile from the HSS and checks the access restriction and other profile items (e.g. QoS Profile) to decide the content of the Inter-System Mobility Policies to offer to the specific subscriber modifying per-subscriber the access reselection decisions.

Subscriber profile based personalization (cont.)


OpenEPC includes the features of the Policy and Charging Control (PCC) architecture that permit to provide QoS provisioning. The gateways of OpenEPC support the BBERF or PCEF functionalities that enforce the policies provided by the PCRF.

Upon attachment a default bearer QoS profile is selected by the PCRF and provided to the gateways. They can enforce the Diffserv class provided for the IP flows and the bandwidth limitations. The bandwidth limitations are performed proactively by setting limits or reactively by activating bandwidth usage monitoring and providing alerts to the PCRF upon usage exceeding the limits.

On service establishment of EPC ready services (e.g. IMS services), the Application Function (AF) requests to the PCRF service authorization and resource reservation identifying which service its being established. PCRF enforces in the gateways different QoS parameters for the connection associated with that service.

QoS provisioning


To access IP Multimedia Subsystem (IMS) services with QoS, IP mobility and security OpenEPC is used. The OpenIMSCore (www.openimscore.org ) provides the perfect extension to the OpenEPC in this area. IMS can be used for Voice over IP (VoIP) or other multimedia services. Independent of the service being used the P-CSCF of OpenIMSCore includes the Rx interface towards the PCRF and requests service authorization and resource reservation from OpenEPC. Moreover the P-CSCF can inform OpenEPC through the Rx interface upon user registration to the IMS that a network connection is being used for IMS signaling, the PCRF supports different configurations which can give preference to that specific bearer over the others.

The P-CSCF can request the PCRF to inform upon events in the IP Connectivity of a subscriber that affect the service given, like the loss of bearer or release of bearer which are supported by the OpenEPC Policy and Charging Control architecture.

Access to IMS services


OpenEPC can be used to connect to plain Internet, in order to make use of the advantages of the communication between the applications and the EPC providing a better control of network usage several solutions are possible.

For demonstrations a HTTP Proxy enabled with the Rx interface can be used. This HTTP Proxy offers several advantages, when requests are identified to known Internet services, the EPC can provide improved QoS and better control. As an example when a user requests access to a known real-time application server (e.g. video portal) through HTTP the EPC provides a better Diffserv traffic class what will offer preferential treatment in gateways upon congestion, reducing latency.

A Deep Packet Inspection (DPI) system with Rx interface can also be used to provide information from the application being used by the user to the PCRF and request preferential treatment. For example a network operator that has an agreement to provide VoIP through Skype would like to guarantee preferential treatment for the Skype flows for its subscribers.

Such a DPI could be integrated within the PDN-Gw of OpenEPC as a module, this will be included in the next releases of OpenEPC. This will require some extensions to the Gx interface which has not been designed to support this use case.

Access to Internet through EPC


OpenEPC Technical Aspects

OpenEPC is a software implementation of a set of standard EPC components which permits the cost efficient establishment of all-IP NGN testbeds to prototype, measure, monitor, test, and perform research developments in the area of next generation of fixed and mobile networks.

OpenEPC is both IPv4 and IPv6 compatible and its components have been developed in C under Linux for high performance.

The specific components that are part of the current release 1 of OpenEPC are:

a S-Gw and ePDG (including a BBERF from PCC Release 8), PDN-Gw (including a PCEF from PCC Release 8), PCRF, HSS, ANDSF, and a corresponding EPCclient.

All these components have been designed to be:

Configurable – allowing easy modification of the behavior of components and the inclusion of optional features.Customizable and extensible – permitting the set-up of different environments and adapting to new requirements that may appear within standardization processReliable – based on the know-how gained in previous component development like the Open IMS Core projectConformant to standards - can be used for testing other commercial components as well


Connection to the OpenEPC

From the access networks

IP connection (v6 or v4)Attachment trigger: DHCP RequestsInstallation of a generic ANGw with or without BBERF, *MIP features, AAA interface etc.

From the Application layers

IP connection (v6 or v4)Signaling to PCRF trough Rx interface for authorization, policing and QoS control


OpenEPC for Research and Development

OpenEPC enables a quick start on the heart of emerging mobile networks, namely the Evolved Packet Core architecture, because of its:

Standards conformance: OpenEPC has been done with the standards in mind; being an independent organization and having commercial deployment out of scope constitutes a great advantage Configurability: OpenEPC can be configured to match your needs for testing only some components or use casesExtensibility: adding new functionality whether new mobility schemes or QoS protocols or other functionality added to the components is as easy as it gets with the modular, standard based OpenEPC architecture

Open EPC aims to provide its users with a basic understanding and practical hands on experiences with EPC, as well as conformance testing. With OpenEPC it is possible to develop functional extensions of individual and/or multiple EPC components and new NGNM showcases.

In addition, OpenEPC supports research and development of challenging aspects of upcoming all-IP NGN infrastructures and services, like the integration of new fixed and wireless access technologies, new approaches to mobility and QoS, or optimizations of the architecture, design of new seamless wireless applications, and the investigation of new business models in the next generation of fixed and mobile networks.


The OpenEPC will be demonstrated to the public at the 5th FOKUS IMS Workshop in November 2009 in Berlin. From this moment the software will be made available to selected partners.

Subsequent OpenEPC releases will be made available in spring 2010 and end of summer 2010 adding more functionalities, interfaces and protocols.

The software is available under license for testing and research activities, either with source code or as binary implementation of individual components or complete platform.

For more information on how to get the OpenEPC refer to:[email protected]

OpenEPC Software Availability


OpenEPC is available under license either as a complete testbed or as individual components for research and development purposes. OpenEPC integrates with various access networks and different services platforms to provide a complete all-IP networks solution.

The planned releases of OpenEPC are as follows:

November 2009: First demonstration of OpenEPC and availability for partners at

5th FOKUS IMS Workshop

Spring 2010: First Release of OpenEPC: will include more mobility options,

roaming configurations support, and support for security procedures

End of Summer 2010: Second Release and full OpenEPC

We are able to provide on-site coaching, local deployment and integration activities, support, as well as extensions to OpenEPC components to meet specific customer requirements.

In the same way Fraunhofer FOKUS and TU Berlin are interested in setting up joint R&D projects based on the OpenEPC platform.

OpenEPC Releases and Roadmap


OpenEPC Architecture

Conformant to the 3GPP Standards

Highly modularized

Configurable

Reliable

Customizable and extensible


OpenEPC Demo in our Labs

Mobility and Personalization

Personalization and QoS Control

Session Adaptation – Mobility and Interaction with Applications

Internet Based Services Integration

IMS Based Services Integration


And we showed the prototype live … so stay tuned for more!


Do you want to see more? Look at our Event Minutes!

Featuring:

• Four tutorials and interactive Workshops on Day 1

related to Rich Communications, Rich Media,

Future Internet and Open NGN / IMS Testbeds

• Social evening event for Networking

• Full day NGN2FI Conference on Day 2

•Many Operator Talks and Vendor Exposition

• FOKUS Playground Visits and Technology Demonstrations


Current R&D Focus: NGN Evolution towards Future Internet

Information Technologies(Service Oriented Architectures)

FutureInternet

Evolution

NextGeneration

Network

Tele

com

mun

icat

ions

Internet

Revolution

Fixed and Mobile Telecommunications

Clean Slate Design

RCS

3/4 Play

FMC

IMSIPTV

PES

Autonomic Communications

EPC

P2P

ServiceArchitectures


NGNI – Next Generation Network InfrastructuresFrom Next Generation Networks to the Future Internet

Evolution towards all-IP converged NGNs

Provision of NGN service and related tools, including integration with legacy networks

Prototyping of converged multimedia applications, e.g. FMC, 4Play & Telco 2.0 applications

Development of Open Evolved Packet Core (OpenEPC)

Strong cooperation with TUB Chair AV

R&D on advanced network and service control protocols and related components for multimedia services, with special focus on:

Reusability, efficiency, reliability, security, manageability

R&D on middleware and Service Delivery Platform (SDP) implementation options above converging networks and Next Generation Networks (NGNs)

R&D on NGN to Future Internet Evolution (NGN2FI)


NGNI – Next Generation Network InfrastructuresEnabling rich multimedia communications over converging networks

Key Projects

Deutsche Telekom Service Broker and Integrated Service Architecture BMBF MAMSplus – Service composition and management for NGN/IMSEU Panlab II (PII) – Federation andmanagement of distributed NGN/Futureinternet testbedsBMBF Project G-Lab_DeepEU PEACE – Emergency supportextensions for IMS-based networkMultimedia session continuity & policy-based QoS control for NGN and LTEVarious industry NGN testbeddeployments with operators

Key Technologies

Open IMS CoreConverged Open Messaging Server (COMS)Anubis Gate – a Telco 2.0 gatewayXPOSER – an OSE-based service brokermyMonster –the Convergent Client FrameworkOpenEPCTeagle – Testbed search tool

Key Laboratories

Open SOA Telco Playground

FI Technologies Lab


Integrative Service Architecture (ISA) Team

Reliable Networking Infrastructures (RNI) Team

Evolving Infrastructure and Services (EIS) Team

NGNI Research Teamsand Testbeds & Tools

• Testbed Federation Tool• FI Crosslayer composition• Semantic Service Composition

• NGN Emergency Support• NGN Security extensions• Identity Management• Seamless Handover Support• Evolved Packet Core

• SOA Network Model.• IMS/P2P Interation• Testbed Security

• SOA based Service Delivery Platforms• Open Network API Gateways• Intelligent Service Brokers• Integrative Service UE Client • Integrative Service prototyping


OpenEPC is just one Toolkit out of much more …


FOKUS all-IP NGN and FI Research, Tools and Testbeds


Contact

If you have questions about OpenEPC, contact the experts at

[email protected]

More information about OpenEPC can be found at

www.openepc.net

open epc tutorial

Documents