Joint 3GPP & TISPAN Workshop on NGN-IMS Agenda item 6:

22-23 June 2004 TISPAN-3GPP Workshop - Sophia-Antipolis 1

Joint 3GPP & TISPANWorkshop on NGN-IMS

Agenda item 6:

Issues related to the reuse of IMS for NGN

and ADSL access to IMS features


Potential Topic issues6.1 Subscription, Databases and Terminals6.2 IMS Enablers 6.3 Security requirements and solutions 6.4 Charging requirements and solutions 6.5 Bearer QoS classes 6.6 Resource allocation and Policy Control 6.7 Capabilities and Services6.8 IP Version and related Interworking issues 6.9 Interconnection to External Networks 6.10 Potential impacts on SIP profile 6.11 Potential impacts on DIAMETER profiles 6.12 Management requirements and solutions6.13 Other topics


Service offering related issues

Dick Knight (BT Group plc)TISPAN WG1 Chairman

[email protected]

6.1 Subscription, Databases and Terminals 6.2 IMS Enablers 6.4 Charging requirements and solutions 6.7 Capabilities and Services


(6.1) Subscription Databases & Terminals

UICC in NGN NGN needs to uniquely identify users not all terminals will be UICC compliant “soft” identities

Requirements flexibility

Identity Issues SIP URL’s

• who will allocate domain names?• 3GPP approach?


(6.1) Customer Networks (1)

3GPP IP-CAN 3GPP IMS3GPP TE

Customer Environment

DSL

Modem

Customer Premises Network

IP-layer

Router

FW/NAT

TE

TE

TE

TISPAN NGNCoreTISPAN NGN Access Network

MEDSLAM

P-CSCF UA

PDF/Gate Controller

DSL modem +

router (IP

NAT/FW)

B-RAS

(+MAG) Private address Space

SIP (private IP addresses)

Gm Gq

Go


(6.1) Customer Networks (2)

TISPAN NGNCoreTISPAN NGN Access Network

DSLModem

Customer Premises Network

App-layerRouter

FW/NAT

TE

TE

TE

ME

DSL modem +

router App layer NAT/FW

DSLAM

PDF/Gate Controller

B-RAS(+MAG)

P-CSCF UASIP-aware

layer(e.g. SIP ALG

or proxy)Security requirements ! Gq

Go

Gm


(6.2) IMS Enablers

Presence; Messaging; Group Management; Conferencing issues related to identity

Presence needs to identify network type not currently in Release 6 Could Presence be extended to PSTN/ISDN?

Conferencing 3GPP approach?

• IETF (XCON)?


(6.4) Charging Requirements and Solutions

Fixed Networks charge on Access Lines But individual services (e.g. Presence) may

need to charge User

Requirements: Flexible approach to charging

• allow access line, individual subscriber and any combination of both

3GPP approach Does this impact WLAN support?


(6.4) Charging Example

Customer ‘A’ has ADSL pays access (rental) all family can use ADSL communications may be an individual charge

Customer ‘B’ uses ‘A’ line pays for personalised services could pay usage charges

Combination of access line charge usage/service charge


(6.7) Services Issues

Standardised Services Service Capabilities key drivers for Services:

• Presence; Messaging; Push to Talk; Gaming

Interoperability Issues Supplementary Services enhancements to voice services

Service Management Issues Managed at capability level What are 3GPP plans?


Security issues

Martin Euchner (Siemens AG)Work Item Rapporteur [email protected]

Scott Cadzow (C3L)STF Leader

[email protected]

6.3 Security requirements and solution


(6.3) NGN Security Objectives

TISPAN NGN has to meet a set of comprehensive and fundamental NGN security requirements to ensure a secure and trustworthy

environment for customers, network operators and service providers

TISPAN NGN Security Release 1 is based upon IMS security needs to enhance IMS security as

appropriate and necessary


NGN Security - Status Quo

There is a real need to investigate on overall security of NGNis being addressed in the TISPAN NGN

Security Architecture & Requirements TS

Current status: capturing NGN security goals, objectives

and requirements

Security requirements and NGN-IMS security gap analysis expected to be stable by September 2004


Some crucial NGNSecurity Issues of Joint Interest

There will be new IMS security requirements from TISPAN NGN from “fixed NGN” space due to “convergence”

Some potential hot areas: Security for supporting xDSL (cable?) scenarios, Interdomain security, interworking of various security mechanisms, Terminal or user authentication (or both),

• HW-based (UICC/USIM/ISIM/SIM) and/orSW-based authentication,

Smooth NAT/FW traversal, Various, unique identities in the NGN environment, Single-sign on? (E2E) media protection, …


Process for NGN Security Standardisation

EnvironmentTelecommunications Changes in the Threat

analysis Countermeasures Threat

analysisCountermeasures

Changes in the Telecommunications Environment


Desired Collaboration with 3GPP

What is the most productive way of collaboration on NGN-IMS security affairs?

SA3 could be the primary point of contact for liaison activity on security other 3GPP SA groups may need to be involved

too

Liaisons with IMS security requirements are expected from September 2004 onwards...


(6.3) Security Backup Slide


NGN Security Requirement Areas

Security Policy Authentication and Authorization Identity and Secure Registration Communications and Data Security

(incl. integrity, replay protection, confidentiality) Privacy Security Management

(incl. security event logging and security audit) Interworking with NAT/Firewall Non-repudiation

Availability, DoS protection, reliability and assurance.

There are many more detailed requirements


QoS related issues

6.5 Bearer QoS Classes

Dave Mustill (BT Group plc)TISPAN WG5 Chairman

[email protected]


(6.5) TISPAN WG5 QoSQoS in an NGN Environment

QoS and Network PerformanceEvolution – from PSTN to NGNWhere Are We Now?QoS in TISPAN_NGN R1Bearer Service NP ClassesConclusions


QoS and Network Performance

QoS is an end-to-end issue Includes terminal and user’s local network Metrics are parameters sensed by user (e.g. delay,

echo, distortion)

Network Performance is UNI-UNI issue Metrics are bit/packet related (e.g. delay, jitter,

packet loss, error rates)

TIPHON confused the two terms – we are trying to be a lot more rigorous in TISPAN.


Actual Performance

Packet loss in high bit rate (core) networks is low (~0.1%)

Delay variation in high bit rate core networks is low compared to fixed delay element

The main NP problems are in the access networks which are expensive and low bandwidth

QoS depends very much on the terminal (e.g. the interactions between the codec and the network)

We have very little practical knowledge of effects of jitter variations on new codecs


Evolution – from PSTN to NGN

Monopoly era Liberalised era NGN era

Significance of impairments

Terminals

Time

Networks


General Principles of Apportionment

Applies to NP not QoS parameters OK for fixed impairments but need to avoid

unlikely worst cases imposing too tight limits

Only a help if we know how to design network to achieve limits

Impairments caused by random events that are not correlated in all networks may need to be treated differently (under discussion in STQ & WG5)


Where Are We Now? We understand

• NP for 64kbit/s circuit switched channels• How to design circuit networks to achieve NP• Interactions of circuit switched channels with low rate codecs• QoS for 3.1 kHz speech (E-model)• Packet handling techniques that improve performance

We do NOT understand• Interactions of packet transmission with new codecs• Interactions of terminal and network signal processing• How to specify NP on IP infrastructure e.g. jitter spectrum• How to design packet networks to achieve NP (relation between

network load and performance) particularly at bandwidth bottlenecks• Level of improvement from packet handling techniques and network

“QoS” mechanisms• QoS for wideband speech


QoS in TISPAN_NGN R1

The TISPAN_NGN should be able to support a wide range of services with defined levels of QoS.

In order to support the required levels of QoS TISPAN will define bearer service NP classes and means of achieving them: QoS control mechanisms QoS control architecture QoS control signalling


Layered Nature of NP & QoS

TISPAN WG5 will specify three levels of “QoS”: Network Performance of the bearer

service between UNIs End-to-end QoS of monomedia

application components (e.g. delay, speech quality, picture quality)

End-to-end QoS of some multimedia application specific parameters (e.g. lipsync)


Bearer Service NP Classes

TIPHON QoS specifications were focused on end-to-end QoS

In an NGN environment, the network performance at the bearer service level should be taken into account

Bearer services are characterised by their NP parameters and their “bandwidth”

The initial focus of TISPAN_NGN will be on bearer service NP Classes, based upon the uses to which the bearer services will be put

These classes should be based on the ITU-T Y.1541 “IP Network QoS classes” and 3GPP TS 23.107 “UMTS QoS classes”


ITU-T and 3GPP QoS Classes (1)

TISPAN WG5 views both ITU-T and 3GPP approaches to IP QoS classes as classes of network performance

There are discrepancies between the two sets of classes which both set out to define a minimum set of QoS classes for the support of a variety of applications on an IP bearer

The main discrepancy is the fact that the 3GPP classes place no requirement on the control of IP packet delay variation (jitter)


ITU-T and 3GPP QoS Classes (2)

Long term harmonisation of the two sets of classes is desirable

In the shorter term the TISPAN WG5 view is that there are two possible approaches that could be adopted in TISPAN: support of both sets of classes (giving ten in all) defining an interworking/mapping function (where

3GPP class x would map to ITU-T class y as a call passed from a 3GPP to an NGN domain)

Even in the short term it will be necessary to determine a way of assessing how much jitter and delay a call will have when handed over from a 3GPP network to an NGN


QoS Summary

Almost all of our knowledge on QoS and NP is based on circuit-switched narrowband speech.

We need implementation experience to develop our knowledge of the QoS and NP requirements of packet-based networks.

There is an urgent need to work on the harmonisation of the 3GPP and ITU-T bearer QoS classes.


Gq interface ssues

6. 6 Resource allocation and Policy control

Leonardo Finizola e Silva (Alcatel) [email protected]

Jörg Ottensmeyer (Siemens) [email protected]


(6.6) Using Gq in TISPAN

Gq Interface is located between Multimedia Subsystem(s) and Resource and Admission Control Subsystem (RACS)

Gq is used by different subsystems (not only IMS) and multiple Access Networks

Gq is used to access the following function: Resource reservation Admission Control NAT Control Gate and Policy Control


(6.6) Gq Extensions

Support for network initiated resource reservations Besides Pull Model the Push model shall be

supported. Support for requesting Address and Port

Translation Parameters for NAT type of scenarios., e.g.

• interworking of different (private/public) IPv4 address spaces, query and allocate NAT bindings

• Possibly IPv4/IPv6 interworking

Gate control and service and network policy control Parameters to access those functions


SIP Profile issues

6.10 Potential impacts on SIP profile

Sébastien Garcin (France Telecom)TISPAN SIP Work Item Rapporteur

[email protected]

Ray Forbes (Marconi)TISPAN WG3 (Protocols) Chairman

[email protected]


Wireline versus Wireless:

Constraints in terms of bandwidth scarcity, security, transmission delay are different.

Terminals:

Different requirements placed on NGN terminals (e.g. support of IPv6, availability of UICC device)

Location Information:

Location information different in nature and usually not available at the terminal.

Resource management:

Explicit resource reservation signalling not available in terminals and access network edge points

Common ressources shared between the signalling and media flows

Regulatory issues :

Different constraints

Inherent differences between NGN IMS and 3GPP IMS


Potential impacts on 3GPP TS 24.229

Relaxing the constraint on IPv6 Potential impact on P-CSCF procedures (modification of IP adressing

in SIP messages) Access call server discovery: since IPv4 is supported, extensions to

DHCPv4 should be considered Relaxing the constraint on UICC availability in UE

Alternative (probably weaker) SIP authentication procedures may have to be taken into account

Impact on trust placed in the terminal

Difference in bandwidth and transmission delay constraints SIP compression seen as optional for the UE Indication of RTCP stream bandwidth in SDP usually seen as optional

for UE SIP timers to be re-considered

Geographic location information Need to update SIP information format (currently P-Access-Network

info) P-CSCF may have to insert this information in SIP messages Should not be systematically removed by the S-CSCF (for location-

dependent services triggered from the called party’s S-CSCF)


Administrative domain of the P-CSCF Not only sent at registration phase but also at session establishment

phase Subject to privacy

Differences in resource reservation procedures P-Media-Authorization headers not required, impact on Preconditions

signalling

Need for SIP body filtering procedures in P-CSCF No dedicated transport channel/resources for signalling in xDSL access

Overriding presentation restricted user information to authorized parties Due to regulatory reasons

Support of SIP-aware residential gateways Impact on security association and NAPT scenarios

SIP support for overlapp sending?

Potential impacts on 3GPP TS 24.229


Other NGN-IMS issues ?

6.13 Other Requirements/Topics, e.g. Common Application Servers access from IMS and from

other Subsystems? Need for direct interactions between resource control entities Relationships between the IMS and NGN modelling (i.e.

service/transport split) ….

No specific input available at this stage ?


Summary NGN-IMS requirements and issues

Requirements Agreed ones Those requiring further joint work

Issues impacting IMS Which specifications Issues requiring further joint work

For discussion and

Possible consensus reach !

Documents

Joint 3GPP & TISPAN Workshop on NGN-IMS Agenda item 6: