NGCN SummitAmsterdam, 18th of May 2010
The Evolved Packet CoreA New Internet Model For The Telecoms A New Internet Model For The Telecoms
World?
Denis GROS-JEAN, FranceTelecom/Orange group
Head of mobile packet core activities
agenda
� the Group in few facts
� EPC architecture
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� Major characteristics
� Conclusions
the Group in few facts
.
a leading telecommunications operator
at end 2009
mobile
customers
193 million customers
3
mobile
132.6 million customers
ADSL Internet
13.5 million customers
revenue
€ 50.9 billion
Orange Mobile footprint
U K
France
Belgium
Luxembourg
Switzerland
Austria
Slovakia
Poland
Romania
Moldova
Jordan
Egypt
Sénégal
Guinée-Bissau
Guinea
Côte d’Ivoire
Mali Niger
KenyaUganda
Guinée
Cameroun
RépubliqueCentrafricaine
Tunisia
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Spain
SwitzerlandRomania
Armenia
Guinée
Equatoriale
BotswanaMadagascar
Mauritius
La Réunion
Dominican republic
Caribbean Islands
Vanuatu
The very big majority of the Orange mobile networks have deployed
a 2G/3G packet core network
EPC: architecture and major characteristics
.
Overall objectives of LTE/EPC design
� The 3GPP work on LTE/EPC aimed at defining a system with:
– Higher data rate
– Lower latency
– Optimized for packet transport
– Natively support various Radio Access Technology
� On access network side:
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On access network side:
– a new radio interface for better spectral efficiency
– evolution towards a flat architecture
� On the core network side:
– Specifications to support several RAT
– Specifications to provide mobility and seamless continuity
– Optimization of the number of nodes crossed by payload packets
– Selection of the most appropriate available access network, to optimize both operator and user experience
EPC Architecture – Complete view with multi-access
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Major Characteristics of Evolved Packet Core 1/2
� Flat architecture and separation of user and data plane: only one node in radio part (eNode B), and potentially one node (gathering S-Gw and PDN Gw) for the data traffic in the CN
– New split of functions between Radio Access Networks and Core
network
– Optimization of the data path
In the CN, reuse of the concept of 3G direct tunneling
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– One node dedicated to the signaling, so full capacity of the node
for the control plane
=> Better End to End performances: reduction of latency of data
traffic, optimization of the attach procedure and session
management establishment.
� The EPC is an all IP network (AIPN)
Major Characteristics of Evolved Packet Core 2/2
� Always-on IP connectivity by default– A default EPS bearer is established as soon as the UE gets attached to
the network and remains connected
– UE reachability from the beginning
– Better performance for the data transfer
– Bearer establishment initiated by the network
– Characteristics of the bearer fully managed by the operator
– QoS model reviewed (reduction of parameters)
– Should allow the setup of End to End QoS from the start
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� Several access types with mobility– 3GPP and non 3GPP accesses
– Several cases of mobility:
1. Intra-EUTRAN mobility: the UE moves from one eNodeB to another eNodeB
2. 3GPP Inter-RAT mobility: the UE moves between E-UTRAN and another 3GPP RAT (i.e. GERAN or UTRAN)
3. Mobility between 3GPP and non-3GPP access: the UE moves between a non-3GPP system (e.g. WiMAX) and a 3GPP system (e.g. E-UTRAN)
4. Mobility between different non-3GPP access: the UE moves from a non-3GPP system (e.g. WiMAX) to another non-3GPP system (e.g. Wi-Fi)
EPC Architecture – Mobility Management Entity
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� Mobility Management Entity is responsible for :
> Non Access Stratum signaling (attach, detach, S-GW selection,…)
> NAS signaling security (authentication, etc.)
> Inter CN node signaling for mobility between 3GPP access networks (terminating S3)
> Idle mode UE Tracking and Reachability (including control and execution of paging retransmission)
> Roaming (S6a towards home HSS)
> Bearer management functions including dedicated bearer establishment.
EPC Architecture – Serving Gateway
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� Serving Gateway is responsible for:
> The local Mobility Anchor point for inter-eNodeB handover
> Mobility anchoring for inter-3GPP mobility
> E-UTRAN idle mode downlink packet buffering and initiation of network triggered service request procedure
> Lawful Interception
> Packet routing and forwarding
EPC Architecture – PDN Gateway
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� Packet Data Network Gateway has the functions of:
> IP address allocation
> Policy Enforcement
> Per-user based packet filtering (by e.g. deep packet inspection)
> Charging Support
> Lawful Interception
> User plane anchor for mobility between 3GPP access and non-3GPP access
EPC Architecture functional entities improved for EPC� SGSN – Serving GPRS Support Node
> A control entity for 2G/3G users authentication (Gr) & mobility management
> Evolution of the SGSN for interworking with EPC nodes
� EPC HSS – Home Subscriber Subsystem with EPC subscribers’ profiles and 3G/2G subscribers’ profiles
� PCRF - Policy Control and Charging Rule Function
> A control entity providing the operators’ policies with chargingand QoS per-EPS bearer.
> Evolution of the 3G PCRF
*
� MSC – Mobile Switching center: evolution for voice and SMS services
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� ePDG – evolved Packet Data Gateway (for I-WLAN access)
> Includes Multi-access SeGW (Security Gateway)
> A control (users authentication and bearer management) and user plane entity for untrusted non-3GPP
> Evolution of the 3G PDGData path for S10 and S12 interfaces
(direct tunnel)* AAA server is used with ePDG for non-3GPP access
Conclusions
� EPC design should allow to answer the current challenges that the operators are facing today:
– Tremendous increase of data traffic with decrease of revenue per Gb
Optimization of the CN architecture (one node dedicated to the signaling part), all IP network should allow to provide better efficiency and to reduce the costs
– Need for always on connections
Always on IP connectivity by default
– New radio accesses
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– New radio accesses
Connection of several radio accesses are specified and mobility as well
– Deployment of QoS mechanisms
Optimization and simplification
� The better performances and the mobility should allow operators to offer new services and new experience to the end users (e.g. combination of voice and data services)
thank you
