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Kamakshi Sridhar, PhD
Distinguished Member of Technical Staff
Director Wireless CTO organization
August 2012
Introduction to Evolved Packet Core (EPC): EPC Elements, protocols and procedures
© 2009 Alcatel-Lucent. All rights reserved.
Agenda
1. Introduction to Evolved Packet Core (EPC) and Evolved Packet System (EPS)
2. LTE and all-IP: What is new?
3. EPC components Serving Gateway (SGW), PDN Gateway (PGW)
Mobility Management Entity (MME), Policy and Charging Control Function (PCRF)
4. LTE core functions and service procedures Core network functions
Network attachment, service requests, paging, IP addressing, handover
© 2009 Alcatel-Lucent. All rights reserved. 3 | Technical Sales Forum | May 2008
1 Introduction to Evolved Packet Core and
Evolved Packet System
© 2009 Alcatel-Lucent. All rights reserved.
LTE: All-IP, simplified network architecture
New, all-IP mobile core network introduced with LTE End-to-end IP (All-IP)
Clear delineation of control plane and data plane
Simplified architecture: flat-IP architecture with a single core
EPC was previously called SAE (System Architecture Evolution)
eNodeB is also called E-UTRAN
Evolved Packet System = EPC + E-UTRAN
What is EPC ?
LTE+EPC
eNode B
IP channel Evolved Packet Core
(All-IP)
Transport (backhaul and backbone)
“The EPC is a multi-access core network based on the Internet Protocol (IP) that enables operators to deploy and operate
one common packet core network for 3GPP radio access (LTE, 3G, and 2G), non-3GPP radio access (HRPD, WLAN, and
WiMAX), and fixed access (Ethernet, DSL, cable, and fiber).
The EPC is defined around the three important paradigms of mobility, policy management, and security.”
Source: IEEE Communications Magazine V47 N2 February 2009 REF: http://www.comsoc.org/livepubs//ci1/public/2009/feb/pdf/ciguest_bogineni.pdf
4 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
Mobile core in 2G/3G
5 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved. 7 | Technical Sales Forum | May 2008
2 LTE and EPC – what is new?
© 2009 Alcatel-Lucent. All rights reserved.
EPC: new all-IP core, new network elements (functions)
EPC elements
LTE/EPC
eNode B
IP channel MME PCRF
PDN GW SGW
GSM
GPRS
EDGE
UMTS
HSPA
Evolved Packet Core
IP channel
Packet Switched Core
PSTN
Other mobile
networks
VPN
Internet
Voice
Channels
GGSN SGSN
MGW
MSC
BSC / RNC
Circuit Switched Core (Voice)
BTS
Node B
Softswitch GMSC
2G/3G
Serving Gateway (SGW)
Packet Data Network (PDN) Gateway (PGW)
Mobility Management Element (MME)
Policy and Charging Rules Function (PCRF)
8 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
EPC elements
EPC elements
LTE/EPC
eNode B
IP channel MME PCRF
PDN GW SGW Evolved Packet Core
Serving Gateway
Serving a large number of eNodeBs, focus on scalability and security
Packet Data Network (PDN) Gateway
IP management (“IP anchor”), connection to external data networks; focus on highly scalable data connectivity and QoS enforcement
Mobility Management Element (MME)
Control-plane element, responsible for high volume mobility management and connection management (thousands of eNodeBs)
Policy and Charging Rules Function (PCRF)
Network-wide control of flows: detection, gating, QoS and flow-based charging, authorizes network-wide use of QoS resources (manages millions on service data flows)
9 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
LTE + EPC elements and interfaces
MME PCRF
SGW
S5/S8
Gx S11
eNodeB
eNodeB
S1-U
S1-MME
S1-U
X2
HSS S6a
S10
PGW
SGi
Rx External networks
Operator Services
Applications
IMS
Internet
ACPs
EPC
IP connectivity layer (Evolved Packet System) = E-UTRAN + EPC
UE
Service Connectivity Layer
CONTROL PLANE (CP)
USER PLANE (UP)
10 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
“Flat IP” = less hierarchy means lower latency
eNode B
Node B BTS data plane
control plane
data plane
control plane
SGSN
PDSN
RNC
BSC GGSN
HA
SGSN
PDSN
RNC
BSC GGSN
HA
GSM
UMTS
CDMA
LTE
MME S/P GW
PGW SGW
direct tunnel
11 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
Key implications on user plane (UP) and control plane (CP)
User plane has many common attributes
with fixed broadband
Broadband capacity
QoS for multi-service delivery
Per-user and per-application policies
Highly available network elements
Control plane gets new mobile-specific attributes
Mobility across networks (and operator domains)
Distributed mobility management
Massive increase in scalability
Dynamic policy management
WCDMA/HSPA GSM/GPRS/EDGE CDMA/EV-DO
PDSN RNC RNC BSC SGSN/GGSN SGSN/GGSN
eNode B
IP channel
LTE MME PCRF
PDN GW SGW Evolved Packet Core
Service Delivery Platforms
12 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
Serving Gateway Local mobility anchor for inter-eNB handovers
Mobility anchoring for inter-3GPP handovers
Idle mode DL packet buffering
Lawful interception
Packet routing and forwarding
Policy, Charging & Rules Function Network control of Service Data Flow (SDF)
detection, gating, QoS & flow based charging
Dynamic policy decision on service data flow
treatment in the PCEF (xGW)
Authorizes QoS resources
Quick Reference:
Overview of EPC components and functionality
internet
eNB
RB Control
Connection Mobility Cont.
eNB Measurement
Configuration & Provision
Dynamic Resource
Allocation (Scheduler)
PDCP
PHY
MME
S-GW
S1
MAC
Inter Cell RRM
Radio Admission Control
RLC
E-UTRAN EPC
RRC
Mobility
Anchoring
EPS Bearer Control
Idle State Mobility
Handling
NAS Security
P-GW
UE IP address
allocation
Packet Filtering
eNodeB: all radio access functions
Radio admission control
Scheduling of UL and DL data
Scheduling and transmission of
paging and system broadcast
IP header compression (PDCP)
Outer-ARQ (RLC)
Mobility Management Entity Authentication
Tracking area list management
Idle mode UE reachability
S-GW/PDN-GW selection
Inter core network node signaling for
mobility between 2G/3G and LTE
Bearer management functions
PDN Gateway IP anchor point for bearers
UE IP address allocation
Per-user based packet filtering
Connectivity to packet data network
Policy
PCRF
Decisions
13 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
All-IP mobile transformation
RNC
Radio intelligence moving to eNodeB
1 2 4
Node B BTS BS SGSN
PDSN
Backhaul (TDM/ATM)
RNC bearer mobility
evolves to the SGW
3
Backhaul transition
to IP/Ethernet
Backhaul (IP/Ethernet)
MSC voice and packet data switching
evolve into the SGW
RNC control distributed
into the MME/eNB
Packet data control
evolves into the MME
CS Core
5
CS and PS evolve into a unified all-IP
domain
Service and mobile aware all-IP network
Evolved Packet Core
MME
PCRF
PDN GW SGW eNodeB
PS Core
GGSN HA
Best effort to e2e QoS
6 7
Internet browsing
to Web 2.0+
2G/3G
LTE
14 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
LTE: more than an evolution for the packet core
Existing paradigm (3G) LTE
Voice Circuit switched (CS)
No (CS) core in LTE
- e2e IP: VoIP (IMS), OneVoice
- Through EPC: OTT, SR-VCC
-Alternatives: CS fallback, VOLGA
Broadband
services Best effort,
Limited expensive “broadband”
Real-time, interactive,
low latency, true broadband QoS
Multisession
data - Rudimentary in 3G (none in 2G/2.5G)
- On request
Based on service data flows (IP flows)
- user-initiated sessions
- network-initiated sessions
QoS
- Driven by UE
-Control-plane intensive setup
- theory: up to 8 CoS, practice: 2 – 4
(voice/control, best effort data)
-Driven by policy management, not UE
-Faster setup through EPC
--9 QoS classes
- End-to-end, associated with bearers
Policy
Management - PCRF introduced in 3GPP R7
- Not widely adopted (static policy mgt used)
Network-wide, dynamic
policy charging and control (PCC)
Mobility
Management - Historically very much aligned (part of) with
RAN
- no RNCs - radio mgt. by eNodeB
- Mobility and session management important
functions of the core
15 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
Example of UMTS QoS mapping to IP (transport perspective)
Conversational
Streaming
Background
Interactive
Mapping UMTS traffic types to IP QoS (DiffServ Code Points)
End-to-end QoS in UMTS
16 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
“Flat-IP” also implies need for a sound QoS mechanism
2G/R99 3G Access
CS PS
IP TDM
LTE (and HSPA)
EPC
IP TDM
IMS
Dedicated radio resource allocation per user Shared radio resource allocation for all users
PS re
sourc
es
CS re
sourc
es
Share
d
reso
urc
es
By nature, 2G and Rel99 3G legacy network
architecture provides dedicated CS resources
ensuring:
Low latency (optimized for voice service)
A guaranteed bit rate for the whole duration of the CS call (even in case of congestion)
Without QoS control in flat-IP mobile networks,
the end-user would experience (e.g. for
voice/video service):
High latency when cell/network is congested
High voice packet loss when cell/network is congested
Degraded perception for the end-user
QoS control becomes mandatory to offer real-time services (Voice, Video or
Gaming) over flat-IP mobile networks
17 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
LTE QoS terms
Service Data Flow = IP flow
SDFs are mapped to bearers by IP routing elements (gateways)
QoS Class Identifier (QCI)
A scalar that is used as a reference to node specific parameters that control packet forwarding treatment (e.g.,
scheduling weights, admission thresholds, queue management thresholds, link layer protocol configuration, etc.),
and that have been pre-configured by the operator owning the access node
Allocation and Retention Priority (ARP)
The primary purpose or ARP is to decide if a bearer establishment/modification request can be accepted or
rejected in case or resource limitation
Guaranteed Bit Rate (GBR)
Maximum Bit Rate (MBR)
Aggregate Maximum Bit Rate (AMBR) (for non-GBR bearers)
QCI + ARP + GBR + MBR + AMBR
bearers
18 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
LTE QCI (QoS Class Identifier), as defined by 3GPP TS23.203
QCI Resource Type Priority Packet Delay
Budget
Packet Error Loss Rate
Example Services
1
Guaranteed Bit Rate (GBR)
2 100 ms 10-2
Conversational voice
2 4 150 ms 10-3
Conversational video (live streaming)
3 3 50 ms 10-3
Real-time gaming
4 5 300 ms 10-6
Non-conversational video (buffered streaming)
5
Non-GBR
1 100 ms 10-6
IMS signalling
6
6
300 ms
10-6
Video (buffered streaming) TCP-based (e.g., www, e-mail, chat, ftp, p2p file sharing, progressive video, etc.)
7 7 100 ms 10-3
Voice, video (live streaming), interactive gaming
8
8 300 ms 10-6
“Premium bearer” for video (buffered streaming), TCP-based (e.g., www, e-mail, chat, ftp, p2p file sharing, progressive video, etc) for premium subscribers
9 9 300 ms 10-6 “Default bearer” for video, TCP-based services, etc. for non-privileged subscribers
From: 4 classes in UMTS and CDMA to: 9 classes in LTE
One of LTE standards goals: backward compatibility with UMTS QoS
19 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
EPC bearer management
Data plane needs to support fine-granularity of QoS and charging enforcement functions beyond transport / bearer level
Uplink (UL) and Downlink (DL) packet filters are defined for each bearer and QoS
enforcements (policing, shaping, scheduling, etc.) are applied
PGW acts as the Policy and Charging Enforcement Function (PCEF) point to maintain
QoS / SLA for each of the bearers (and SDFs)
eNodeB SGW PGW peer UE
LTE-Uu S1 S5/S8 SGi
End-to-end service
EPS bearer External
bearer
Radio
bearer
S1
bearer
S5/S8
bearer
E-UTRAN EPC Internet
20 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved. 21 | Technical Sales Forum | May 2008
3 EPC elements
© 2009 Alcatel-Lucent. All rights reserved.
eNode B
MME SGW
eNodeB (E-UTRAN) (not a part of the EPC), but let’s look at…
Interactions with other functional elements
eNode B
MME SGW
UE
eNode B
Pool of SGWs Pool of MMEs
Other eNodeBs
• Mobility Management
• Bearer handling
• Security settings
• Radio Resource
Management
• Mobility management
• Bearer handling
• User plane data delivery
• Securing and optimizing
radio interface delivery
• User plane tunnels for
UL and DL data delivery
• Inter eNodeB handovers
• Forwarding of DL data
during handovers
User Equipment
CONTROL PLANE (CP)
USER PLANE (UP)
22 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
Mobility Management Entity
MME controls how UE interacts with the network via non-access stratum (NAS) signalling
Authenticates UEs and controls access to network connections
Controls attributes of established access (e.g., assignment of network resources)
Maintains EPS Mobility Management (EMM) states for all UE’s to support paging, roaming and handover
Manages ECM (EPS Connection Management) states
eNode B
IP channel
MME is control plane element that manages network access and mobility
MME PCRF
PDN GW SGW Evolved Packet Core
23 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
MME SGW
MME:
Interactions with other functional elements
MME SGW
UE
eNode B
SGWs Other MMEs
Other eNodeBs
• Handovers between MMEs
• Idle state mobility between MMEs
• Authentication and Security
•Location management
• User profiles
• Control of user plane tunnels
• Inter eNodeB handovers
• State transitions
• Bearer management
• Paging
User Equipment
MME
HSS
eNode B
CONTROL PLANE (CP)
USER PLANE (UP)
24 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
Serving Gateway and Packet Data Network (PDN) Gateway
SGW is local mobility anchor
Terminates (S1-U) interface towards E-UTRAN
Local anchor point for inter-eNB handover and inter-3GPP mobility
Support ECM-idle mode DL packet buffering and network-initiated service request
IP routing and forwarding functions
PGW is IP anchor for bearers
Terminates (SGi) interface towards the PDN
Provides UE IP address management (allocation)
Provide Policy and Charging Enforcement Function (PCEF)
Per-SDF based packet filtering
Interface to Online and Offline Charging Systems
eNode B
IP channel
eNode B
MME PCRF
PDN GW SGW Evolved Packet Core
25 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
MME PGW
SGW:
Interactions with other functional elements
MME PGW
eNode B
PGWs MMEs
Other SGWs
• Control of GTP tunnels and IP service flows
• SGW Mobility control
PMIP S5/S8
• IP service flow <-> GTP tunnel
mapping information
GTP S5/S8
• Control of GTP tunnels
• GTP tunnels for UL and DL
data delivery
PMIP
• IP service flows
• User Plane tunnels for
DL and UL data delivery
SGW
eNode B
SGW SGW
•Indirect forwarding of DL data
during handovers (in S1-U)
when direct (X2) inter-eNodeB
connection is not available
PCRF
eNodeBs
PCRF
CONTROL PLANE (CP)
USER PLANE (UP)
26 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
PGW:
Interactions with other functional elements
SGWs
• Policy and Charging Control requests
• PCC rules
• IP flows of user data
PGW
SGW SGW
• Control of User Plane tunnels
• UP tunnels for UL and DL data
delivery
PCRF
External networks
PCRFs
Online Charging
Systems
Offline Charging
Systems
CONTROL PLANE (CP)
USER PLANE (UP)
27 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
End-to-end protocol stack (User Plane)
MAC
RLC
PDCP
L1
S1-U LTE-Uu
eNodeB UE
L2
UDP/IP
GTP-U
L1
S5/S8
L2
UDP/IP
L1
L2
UDP/IP
L1
L2
UDP/IP
L1
MAC
RLC
L1
PDCP
SGW PGW
SGi
IP
applications
services
* S5/S8 reference point between S-GW and PDN-GW can also be GTP based
Key role of S-GWs and PDN-GWs = to manage the user plane (bearer traffic)
user traffic = end-to-end IP
eNode B
IP channel MME
PCRF
PDN GW
SGW
Evolved Packet Core
GTP-U
RELAY IP
GTP-U GTP-U
RELAY
28 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
PCRF:
Interactions with other functional elements
SGWs
• Policy and Charging Control requests
PCRF
SGW SGW
PGW
External networks
PGWs
AF
PGW
• Policy and Charging Control requests
• PCC rules
• QoS rules when S5/S8 is PMIP
• QoS rules when S5/S8 is PMIP
• QoS rules for mapping IP service flows
and GTP tunnel in S1 when S5/S8 is
PMIP
CONTROL PLANE (CP)
USER PLANE (UP)
29 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
Policy Charging and Control (PCC) Architecture
BBERF
BBERF = Bearer Binding and Event Reporting Function
OCS = Online Charging System
OFCS = Offline Charging System
PCEF = Policy and Charging Enforcement Function
SPR = Subscription Profile repository
OCS SDF-based credit control
OFCS
AF
PCEF
Gy
Gz
PCRF
Rx
Gx Gxx
SGW PGW
SPR Sp
30 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
Service level policy control
The PGW needs to support fine-granularity of QoS and charging enforcement functions
beyond transport / bearer level
Multiple Service Data Flow (SDF) can be aggregated onto a single EPS bearer
Uplink and downlink packet filters are defined for each bearer, and QoS enforcements
are applied
PDN-GW
IP-Connectivity Access Network Session UE-IP1@
Dedicated bearer (GBR) UE-IP1@
UE
Default bearer
SDF-1
SDF-3
SDF-2
UE-IP1@
Service Data Flow (SDF)
• Packet filters
• QoS parameter: QCI, Guaranteed bit rate (UL/DL),
Maximum bit rate (UL/DL), Aggregate maximum bit rate
31 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved. 32 | Technical Sales Forum | May 2008
4 Core procedures
© 2009 Alcatel-Lucent. All rights reserved.
EPC: Core functions and service procedures
Core Functions
Charging
Subscriber management
Mobility management (new!)
Bearer management
Policy management (new!)
Interconnection
Core Procedures
Network attachment
Service requests (paging, buffering)
Handovers and (X2 routing)
Roaming (home/visiting PDN breakout)
Interworking with 3GPP ANs
Interworking with non 3GPP ANs
(EVDO/EHRPD treated as a special case)
33 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
Roaming – breakout through home PDN
SGi
GERAN
UTRAN
S11
S3
S8a
HSS
S4
S1-U
S1-MME
MME
S6a
SGSN
S12
HPLMN
VPLMN
X2
Gx Rx
H-PCRF
eNode B
PDN Gateway
Serving Gateway E-UTRAN
Home Operator’s IP Services
eNode B
35 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
Roaming – local breakout (through visiting PDN)
GERAN
UTRAN
S11
S3
HSS
S4
S1-U
S1-MME
MME
S6a
SGSN
S12
HPLMN
VPLMN
X2
Rx
H-PCRF
eNode B
Home Operator’s IP Services
SGi S5 PDN
Gateway Serving
Gateway IP Network
eUTRAN
eNode B
V-PCRF
Gx
S9
E-UTRAN
36 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
IP address assignment
Network attachment and IP address assignment
S7c
SGi S11
S5
E-UTRAN S1-U
S1-MME
MME
Serving Gateway
PDN Gateway
IP Network
S7
X2
PCRF
Always-on IP connection is established and anchored at
PDN-GW
eNode B
eNode B
IP
IPv4 direct
IPv4 via DHCP (after)
IPv6 /64 stateless
IPv6
IPv6 shorter
37 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
UE and service requests
S7c
SGi
S11
S5
E-UTRAN S1-U
S1-MME
MME
Serving Gateway
PDN Gateway
IP Network
S7
X2
PCRF
1. UE sends NAS Service Request
message towards MME
2. Update Bearer Request is sent to the S-GW to establish/modify
S1-bearer
3. Dedicated bearer established after
interaction with PCRF
eNode B
eNode B
38 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
eNode B
Handover and X2 routing
SGi
S11
S5
E-UTRAN S1-U
S1-MME
MME
Serving Gateway
PDN Gateway
IP Network
X2
S7c S7
PCRF
eNode B
eNode B
X2 = active mode mobility
- User Plane (UP) ensures lossless mobility
- Control Plane (CP) provides eNB relocation capability
UDP
IP
L2
L1
GTP-U
UDP
IP
L2
L1
GTP-U
eNB eNB
X2-U
SCTP
IP
L2
L1
X2-AP
SCTP
IP
L2
L1
X2-AP
eNB eNB
X2-C
X2 protocol stacks
39 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved. 40 | Technical Sales Forum | May 2008
4a SMS and legacy voice
© 2009 Alcatel-Lucent. All rights reserved.
SMS service for initial “data-only” devices
Data and SMS only
Handset uses LTE network where possible to achieve highest throughput
Handset served by an MSC in legacy network for voice and SMS
SMS delivered over SGs – without requiring inter-RAT handover
GERAN
UTRAN
SGSN
MSC
CS Network
PDN
E-UTRAN
eNode B
PGW SGW
MME
Data
Paging/SMS
New interface “SGs” from MSC to
MME
SMS-C
41 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
GERAN
UTRAN
SGSN
MSC
CS Network
PDN
E-UTRAN
eNode B PGW SGW
MME
GERAN
UTRAN
SGSN
MSC
CS Network
PDN
E-UTRAN
eNode B PGW SGW
MME
Voice support using “CS Fallback” (CSFB)
Simultaneous Voice + Data
Handset falls back to legacy circuit coverage for voice
Incoming calls to MSC trigger paging over SGs and delivered via MME
Data sessions handover to SGSN if possible
Tradeoff:
Re-uses legacy circuit infrastructure
But at the cost of Inter-RAT handover per voice call, and reduced capacity (3G) or
suspended (2G) data sessions
Data
Data
Circuit Voice
Paging/SMS
New interface “SGs” from MSC to
MME
42 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
GERAN
UTRAN
SGSN
MSC
CS Network
PDN
E-UTRAN
eNode B PGW SGW
MME IMS TAS
SCC AS
GERAN
UTRAN
SGSN
MSC
CS Network
PDN
E-UTRAN
eNode B PGW SGW
MME IMS TAS
SCC AS
Voice via IMS
Simultaneous Voice and Data on LTE
Handset has concurrent access to:
1. Data services including internet access
2. IMS Services including VoIP end-end calling
3. IMS interworking towards legacy
PSTN/PLMN networks
Uses IMS nodes “Telephony Application
Server” (TAS) and “Service Centralization and
Continuity Application Server” (SCC AS)
IMS Services outside of LTE coverage
For service transparency, IMS Centralized
Services (ICS) provides IMS services even
when the handset is out of LTE coverage
Handset has concurrent access to:
1. Data Services including internet access
2. IMS Services including circuit-mode
transport of voice path
3. Calls to-from the PSTN/PLMN legacy
network as well as calls to VoIP end users
in IMS
1
2
3
1
2
3
Circuit Voice Packet Voice IMS Signaling Packet Data Circuit signaling
43 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
Alcatel-Lucent EPC Solution
Gxc
SGi
GERAN
UTRAN
S11
S3
S5/S8
8650 SDM
HSS
S4
S1-U
S1-MME
S6a
7500
SGSN
IP Network
Gx
X2
AFs 5780 DSC
(PCRF)
7750 SR
Serving
Gateway
S101
S12
7750 SR
PDN
Gateway
CDMA/EVDO 9271
eRNC
HSGW
S2a
9471
MME
9326 eNB
Data Plane
Control Plane
Rf Ro
8615
IeCCF
OFCS 8610
ICC
OCS Gn Gp
UE
eUTRAN
9326
eNB
5620 SAM
End-to-end IP management (incl. services)
44 | Introduction to EPC | July 2010 | v6
© 2009 Alcatel-Lucent. All rights reserved.
Alcatel-Lucent
Ultimate Wireless Packet Core
7750 Service Router
Mobile Gateway
9471 Wireless
Mobility Manager 5780 Dynamic
Services Controller
5620 SAM
Service Aware Manager
User Plane Scalability First mobile gateway
to deliver over 100 Gbps
Deployment Flexibility As SGW, PGW/GGSN
or combo
Performance/QoS Per-UE, per-app, per-flow
hierarchical QoS
Reliability 99.999+ % field proven 48,000+ units shipped
7750 Service Router-based Architecture
Optimized split of router and gateway functions
Control Plane Scalability Millions of subscribers Thousands of eNodeBs
Deployment Flexibility As SGSN, MME
or SGSN/MME combo
Performance Superior paging capabilities
High-signallng loads
Reliability Geo-redundancy, pooling No single point of failure
Platform/Architecture ATCAv2 platform
for all CP functions
Full UP and CP Management Full GUI management
of bearers (UP and CP)
Deployment Universality e2e wireless IP management:
RAN, core and backhaul
Integration in OSS/BSS Part of full NM portfolio Full OSS/BSS integration
Reliability Geo-redundancy
Scalability/Architecture Suited for Tier X to Tier1 operator environments
Mobile Core Business Engine Policy Convergence
Monetization and Personalization
Deployment Agility Flexi rules engine with wizards
Up and running in minutes Add new rules easily
Integration with NM Part of full NM portfolio Same NM/GUI paradigm
Reliability Geo-redundancy
No single point of failure
Platform/Architecture ATCAv2 platform
for all CP functions
© 2009 Alcatel-Lucent. All rights reserved.
www.alcatel-lucent.com
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