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LTE and Roaming

John Boggis, GSMA-IREG-RILTE Chair

Document Number GSIF 2010

Meeting Date 29th Nov to 3rd Dec 2010,

Meeting Venue Yokohama, Japan

For Approval

For Information X

Version 1.0

Security Classification Non- Confidential

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� LTE Data-Card Roaming

� LTE IMS Voice Roaming

� IPX Progress

Contents

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LTE Data-Card Roaming

� Vision for LTE

� 3GPP Standards

� Trials at LSTI

� Architecture for “Data-Card” Roaming

� S6a Interface

� Diameter Protocol

� Impact on Carriers

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From Requirements Setting to Standards

� 2005 Position Paper drafted by 4 operators.� White Paper 3.0 “Next Generation Mobile Networks-Beyond HSPA &

EVDO” published Dec 2006 by 7 operators

� NGMN membership 2010 - 18 Operators-37 Manufacturers

� March 2009- 3GPP Release 8 Specifications approved� March 2010- 3GPP Release 9 Specifications approved

From Vision……to Standards

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The Standards

� Mobile Broadband

� 100Mb/s Downlink; 50Mb/s Uplink ; 20Mhz bandwidth

� 3-5 times spectral efficiency of HSPA� 30 ms end-to-end round trip latency

� Always on

From Vision……to Standards

• 100+ new 3GPP R8 Specifications

• 150+ enhanced Specifications

• 50+ active companies

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LTE SAE Trial Initiative (LSTI)

Becoming A Mature Technology For Mobile Broadband

From Standardisation……to Commercial Rollout

InteroperabilityIOT: First results for Air Interface

and S1&X2 interface delivered

Friendly Customer TrialsActive Trials

delivering first results

Proof of Concept completedConcept

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LTE Initial Roaming Architecture (Datacard)

HSS

MME

H-PDNG/W

SGWV-PDN

G/W

V-PCRF

H-PCRF

Services

S6a S8 S9

Visited Network

Home Network

E-UTRA

User plane

Control plane

Future scope

HSS Home Subscriber Server

LTE Long Term Evolution (Radio)

MME Mobility Management Entity

PCRF Policy and Charging Rules FunctionPGW PDN(Packet Data Network) Gateway

SGW Serving Gateway

S6a Diameter (Mobility Mgmt) replaces MAP

S8 GTP – as used for GPRS & UMTS

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S6a Interface

� Interface between the HSS (Home Subscriber Server) and the MME (Mobility Management Entity).

� Enables transfer of subscription and authentication data for authenticating/authorising user access to Evolved Packet Core. (E.g. similar function to Gr Interface in 3GPP UMTS Packet Core between HLR and SGSN).

� Defined within 3GPP TS 29.272, based on the Diameter Protocol.

� Why Diameter, instead of MAP:-

– Move away from SS7-signalling transport in the core network (e.g. MTP-

based, SIGTRAN-based) towards a pure IP signalling transport (e.g.

TCP, SCTP).

– Diameter protocols adopted within IMS architecture for HSS (Cx and Sh

Interfaces) and within PCC architecture.

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What is Diameter?

� Diameter Base Protocol is defined within IETF RFC 3588, published in September 2003.

� Originally developed as existing AAA protocols (e.g. RADIUS) did not satisfy the requirements of evolving networks:-

– Failover Mechanisms – application-layer acknowledgements

– Transmission-level Security – IPSec and TLS

– Reliable Transport – SCTP and TCP

– Agent Support – Proxies, Redirects, Relays

– Server-Initiated messages

– Capability Negotiation and Error Handling

– Peer Discovery and Configuration – Support of DNS

– Roaming Support – via support of proxies, transmission layer security,

and host/realm-based routing.

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� All Roaming Interfaces are IP based

� Increased usage of GRX/IPX due to higher user-data rates.

� Additional IP protocols required

� SCTP expects consistent latency and low packet loss.

� SS7 not used for Authentication, Registration or Subscription Management.

� SS7 remains for SMS (SMS-over-SGs)

LTE Data Card Roaming - Impact on Carriers

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� LTE Data-Card Roaming

� LTE IMS Voice Roaming

� IPX Progress

Contents

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� Background to AATF Commercial and Direct Media requirements

� Routing cases

� IMS-IMS NNI current architecture

� Local Break out

� Target Voice-over LTE High Level Roaming Architecture

� Roaming and Interconnect interfaces

� Impact on Carriers

LTE IMS Voice Roaming

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Design Requirements

� Voice call routing for Voice over LTE when call originator is Roaming should be at least as optimal as that of current CS Domain. This means that the bearer path for a VoLTE call should be routed from the Visited network of a Roaming call originator to the terminating network.

� The charging model for roaming used in CS Domain shall be maintained in VoLTE.

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Current “Data Roaming Architecture”

VPMN (a)

VPMN (b)

HPMN (a)

HPMN (b)

a

b

Services

Services

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Current Voice Roaming Architecture

VPMN (a)

VPMN (b)

HPMN (a)

HPMN (b)

a

b

Mobilty Mgmt

And CAMEL

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Target IMS Voice Roaming Architecture (minimum)

VPMN (a)

VPMN (b)

HPMN (a)

HPMN (b)

a

b

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Target IMS Voice Roaming Architecture (optimised)

VPMN (a)

VPMN (b)

HPMN (a)

HPMN (b)

a

b

Media Control

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Simplified IMS-IMS NNI current architecture

UE

P-CSCF I-CSCF

TASP-GW IMS-AGW

VPMN of A party HPMN of A party

IBCF

TrGW

S-CSCF

UE I-CSCF

TAS

P-GW

IMS-AGW

VPMN of B party HPMN of B party

TrGW

S-CSCFP-CSCF

IBCF

IBCF

IBCF

HSS

HSS

Routing of

user plane

Routing of

control plane

Mw

MmMb

Mw

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Glossary

HPMN Home Public Mobile Network

H-PCRF Home Network – Policy and Charging Rules Function

HSS Home Subscriber Server

IBCF Interconnection Border Control Function

I-CSCF Interrogating - Call Session Control Function

IMS-AGW IMS Access Gateway

P-CSCF Proxy - Call Session Control Function

P-GW Packet Gateway

TAS Telephony Application Server

TrGW Transition Gateway

UE User Equipment

V-PCRF Visited Network - Policy and Charging Rules Function

VPMN Visited Public Mobile Network

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VPMN Break-Out

Services

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/

Target Voice-over LTE High Level Roaming Architecture

UE SGW PDN

GW

Home Network

Visited Network

HSS

P-CSCF

H-PCRF

V-PCRF

S-CSCF AS

IMS

S9 Mw

IP Interconnect

Network

IPX

Key:Media plane

Control Plane

IMS-AGWUE SGW PDN

GWSGWSGW PDN

GW

Home Network

Visited Network

HSSHSS

P-CSCFP-CSCF

H-PCRFH-PCRF

V-PCRFV-PCRF

S-CSCFS-CSCF ASAS

IMS

S9 Mw

IP Interconnect

Network

IPX

Key:Media plane

Control Plane

IMS-AGWIMS-AGW

Mb

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Interfaces

HPMN - VPMN� Mobility Mgmt

– HSS to MME S6a Diameter (supersedes MAP-SS7)

� Policy and Charging Rules– hPCRF to vPCRF S9 Diameter

� IMS Signalling– P-CSCF to S-CSCF Mw SIP

HPMN – Interconnect� IMS Signalling

– S-CSCF(a) to S-CSCF(b) Mm SIP

VPMN – Interconnect� IMS Media

– IMS AGW(a) to IMS AGW(b) Mb RTCP/RTP

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� Local Break-out

� Direct Media Routing

� Separation of Signalling (SIP) and Media (RTP)

LTE IMS Voice Roaming - Impact on Carriers

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� LTE Data-Card Roaming

� LTE IMS Voice Roaming

� IPX Progress

Contents

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IPX Progress

� Progress Summary

� IPv6

� Number of IPX in a chain

� Peering Points Status

� i3F Relationship

� TDM Break-out

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IPX Progress- 1

� IPv6

– Increasing incorporation of IPv6 into IP design activities

– Internal Reference Documents being enhanced

– Address Management; Use same process as with v4 process

– GSMA-EMC IPv6 Task Force concludes “end 2010”.

� IPXs in a chain

– Generally maximum of two

– More than two allowed only for Packet Voice Interconnect (PVI), but

recommendation is that this be the exception rather than the norm.

• QoS, SLA and security requirements also must still be met.

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IPX progress - 2

� Peering points

– Europe Amsterdam 23 members

– Asia Singapore 14

– N.America Ashburn (VA) 8

– Improving Regional Connectivity -> Improved Quality

� IPX/i3F harmonisation

– TDM/PSTN break-in and break-out

• Allow IPX Provider to perform TDM/PSTN break-in and/or break-out

• This is “Work in progress”

– IREG is reviewing of i3F document “"Technical Specification for Voice

over IPX service – Release 1”

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Thank You