IP networking & MEDIACOM-2004 ITU Workshop « IP networks towards NGN » Geneva, 24-27 April 2001 ( E dition 2 du 18 0

1. IP networking & MEDIACOM-2004 ITU Workshop« IP networks towards NGN »Geneva, 24-27 April 2001(Edition 2 du 18 04 01) Gaël Fromentoux Renaud Moignard Christine Pageot-Millet André Tarridec FT R&D/DAC

2. Outline • Introduction • Proposed definitions • IP services & network current state • VoIP • Control plane architecture & QoS • Mobility & nomadism • IPv6 migration. • Conclusion • References & Glossary

3. Introduction • In this paper, it is first proposed a set of definitions to characterise NGN solutions & in particular a so-called " target NGN ". • It is then applied to the services and network evolution of an IP domestic network whose final state would be compliant with the proposed " target NGN ". • Important matters related to this evolution are briefly evoked : • IP services & network current state, • control plane architecture & QoS, • VoIP, • Mobility & nomadism , • IPv6 migration. • As a conclusion, possible synergies between IP, mobile and telephony networks evolution towards NGN are pointed out.

4. Proposed definitions : NGN • A set of definitions based upon functional architecture principles • Proposals aim at helping to provide a common understanding and vocabulary related to NGN matters. • NGN solutions are characterised by the following main attributes: • A services control layer independent from the bearer resources, • A network service layer in packet mode (ATM, IP...), • Open and better standardised interfaces, between the services control & the resources control, • The externalisation of part of the control functions with regards to the transfer layer. • The expected advantages from architectures compliant with those principles are : • The set up of a business model on line with the fast moving telecommunications environment • The ability to support any kind of services & to make them evolve at their own pace, • Architecture flexibility gained from the independence between services and bearer resources, • Resources mutualisation stemming from the two preceding points, • The use of any kind of transmission support (ADSL, SONET, SDH, WDM, radio...). Note that some solutions are already labelled NGN ones although they do not respect the whole set of rules proposed here.

5. Proposed definitions : Target, Telephony & Data NGNs • Definition : a NGN is a “ Target NGN " in case it supports all kinds of telecommunications services and meets the proposed NGN features. • Definition : a NGN will be labelled “ Telephony NGN " when it is at least able to support the whole set of existing telephony services (plain, enhanced and IN services) with matching Quality of Services, QoS. A “ Target NGN ” includes services supported by Telephony NGNs & those by Data NGNs. • Target NGNs can be considered as the final evolution of these two ones. • Definition : a NGN will be labelled “ Data NGN ” when it is not able to support the whole set of existing telephony services (plain, enhanced and IN services) with matching Quality of Services.

6. « transit NGN » Control Platform : Call Server, Gatekeeper, Bandwidth broker,… PSTN, ISDN PSTN, ISDN « core NGN » GW LEX RSU RSU LEX GW NA Concentrating Multiplexing Local switching Long haul switching Access Edge Core Local Proposed definitions : Core & Transit NGNs • A « core NGN » covers core network part. It interconnects edges & offers access to international networks • A « transit NGN » interconnects local networks to packet network cores. > great interest for inhomogeneous networks, for migration, when traffics sources are scattered etc …

7. Services Control Platform Services Control Platform or Local control Platform (Call Server d’Appel, Gatekeeper, Policy server, Softswitch, MGC, …) « Local NGN » Local control Platform NA Concentrating Multiplexing Local switching Long haul switching Access Edge Core Local Proposed definitions : Local NGN • A network solution will be labelled a “ Local NGN ” when it covers the access and edge network parts. • To support a large range of services • To collect various accesses of different kind To emulate LEX functions is just not enough.

8. End users Always On Not Always On To Collect & To Deliver IP network Services To Transport IAP/ISP IP services and network current state : IP network • IP networks provide best effort data services > to residential customers, professional customers & companies. > Internet, Intranet and Extranet connectivity is possible. • Two main services • > aggregation services to collect the traffic of • Not always on customers to deliver it to IAPs/ISPs, • > transport services to convey the traffic of always connected users between sites directly attached to the IP network and towards Internet. • Only best effort services based on the IPv4 protocols are available. > No service differentiation through differentiated • Service classes, no QoS guarantee. • Over provisioning is the remedy. • Voice services such as VoIP, Internet Call Waiting, • Centrex IP may be supplied

9. IP Network IP network current state • 3 parts : access, edge and core. • The access part collects and concentrates customers • traffic through 2 Access Server types : • NAS for narrowband switched connections • BAS for broadband permanent connections. • 2 kinds of NAS : data-oriented and voice-oriented NAS. The edge part concentrates the traffic and performs specific edge functions ( flow classification & conditioning, external routing protocols processing & network-based VPN handling). Edge and border routers support interfaces with the access network, internal servers, ISPs/IAPs & Internet. The core part routes and forwards aggregated flows over core routers. MPLS improves the traffic engineering and supports network-based IP VPNs.

10. IP networks limitations : > no QoS guarantees and no differentiated services as required by some users and applications, > no service control servers on top of the call servers for value-added services, > no service portability over different access networks, > no service portal. • IP networks features consistent with NGN features : > separation of transport resources from AAA servers and call control, > service portability over a given access network, > use of a packet transport to support every service (data, voice). IP network : NGN like features

11. Management Service plane Application server SCP SCP/IP API INAP INAP/IP Gatekeeper or Proxy SIP SS7 CCF Sigtran H323 or SIP H323 or SIP SG PSTN IP GW LEX IP VoIP (H.323 & SIP) general architecture • VoIP : H323 (ITU) & SIP (IETF). • The GK is the control platform. It controls end points (GW & terminal) of a H.323 domain & performs call request (call admission). • GWs perform IP/PSTN inter-working for media stream • SGs for SS7/IP signaling inter-working. • Supplementary services services could be performed within a SCP via an INAP/IP interface or within an application server via API or proprietary interfaces. • VoIP can be considered as a “ Data NGN ”: MM services i.o telephony services. No absolute QoS is available. • VoIP architectures may reach Target NGN by introducing QoS & telephony services. Mobility is still missing.

12. SLA SLA C U S T O M E R S U P P L I E R SERVICES SUPPLIER RESOURCES SUPPLIER ACCESS QUALITY SERVICES CONTROL RESOURCES CONTROL 1 QoS - NP CUSTOMER USER USER Transfer need 2 TRANSFER QUALITY RESOURCES T Control plane architecture & QoS • Control Plane: Services & Resources • Services control: to analyze services requests independently from the resources • Resources control: to select & monitor resources after the request (routing & path algorithms) • Resources mediator to be found QoS • It is a major requirement for the next generation IP networks. Voice, videoconf & streaming cannot cope with best effort. Customers have differentiated needs requiring differentiated QoS levels • IP networks to support several QoS levels absolute QoS, relative QoS and best effort. • Unlimited bandwidth is not ready yet • The Integrated & Differentiated Services models as first steps whereas MPLS is under deployment • QoS is an end-to-end issue, concerns every layer of the transfer plane, requires coordinated mechanisms & procedures in the transfer, control & management planes • A full QoS support is very complex to implement Its introduction will be progressive

13. MSCS & SGSNS GMSCS & GSGSNS PSTN MM IP NGN introduction in CS and PS domains – post R5 architecture. • 2 domains : PS & CS in UMTS R5 • An Internet Multimedia Subsystem (IMS) is introduced. The PS domain associated with the IMS allows UMTS R5 to offer VoIP services • CSCF controls admission, incoming calls and communicates with HSS, (Home Subscriber Server), which is a customer database dealing with mobility and service profile • MGCF controls gateways that perform PSTN/IP network inter-working between • SIP protocol has been chosen by 3GPP for UMTS R5. From a strict functional viewpoint, except for the mobility aspect, a CSCF is a SIP server • Post R5 release proposes an evolution of PS domain towards NGN: externalization of some control functions in SGSNserver & GGSNserver SCP Application servers Application API CAP Network Service & Control CSCF HSS MGCF T-SGW Transport MGW, GSN UTRAN • 3GPP2 is considering IP for the mobility management. Mobile IP is a key component of "full IP" scenarios.

14. Home Agent NC IP network Home subnetwork Sub network Data Foreign Agent Register Visited sub network NM Mobile IP : architecture & principles • 3 main elements compose the • mobile IP architecture : • Mobility function within the terminal to perform moving detection function & registration functions to a HA or a FA. • HA function in the router that connects the H sub-network of the mobile is in charge of updating the information DB for mobile location & reemitting to data to its current location • FA function in the router that connects the V sub-network of the mobile. It registers visiting mobiles & offers services such as datagrams routing to visiting mobiles. • Mobile IP to manage macro-mobility • at the IP level. Mobile IP mainly allows: • communication hold-on when a mobile moves from an IP sub-network to another, • the use of the same IP address attached to a mobile and valid in all IP networks. • As a conclusion IP network could both handle macro-mobility (e.g. in target NGN and partly in UMTS networks) and telephony services, thanks to respectively mobile IP and to SIP or H323 architectures.

15. VHE : a distributed user profile • To trace a user to know its profile and how to recognize it : the Virtual Home Environment (VHE) concept “ a system concept for personalized service portability across network boundaries and between terminals ". ( ETSI 3GPP ) • These concept have been designed in the UMTS networks context : to allow users to always have a common look and feel of their service. No difference for users while they roaming in other networks. • VHE will be created by a combination of capabilities handled by service providers, network operators and located within terminal equipments. • The initial definitions still hold in a non UMTS context (a global service provider for a consistent view of its customers being potentially mobile, fixed and Internet customers. • With regards to this perspective global operators would gain to share a common understanding of : The models that describe their customer (i.e. data attached to their customer), The functions that allow services to be delivered to their customer (i.e. applications dealing with customers), The equipment running these applications and the associated databases.

16. IPv6 : to fix IPv4 limitations • IPv6 to meet the requirements for a large-scale worldwide deployment. • IPv6 supports a number of enhanced features, such as : • larger unicast and multicast address space, • anycast address, • aggregatable addressing for hierarchical routing, • host address auto configuration, • easy site renumbering, • flow identification for QoS support, • streamlined packet formats for improved forwarding performance, • multicast support (explicit scope), • extension headers used for supplementary capabilities, • security providing packet authentication and encryption, • mobility improvement through auto configuration, security, anycast address and destination options. • Given the large amount of IPv4 equipment currently deployed in public & private networks both protocols will coexist for a long time. • Several transition mechanisms have been incorporated in the IPv6 design to help with the migration phase.

17. IP network towards a possible Target NGN … lots of work ahead !

18. Conclusion • A variety of networks have been deployed more or less dedicated to a particular service. • Most of the past technical constraints are no longer valid given the fast evolution in architectures and broadband technologies (control/transfer plane evolution, xDSL, UMTS, DWDM, packet transfer) • Many legacy networks are evolving towards Next Generation Networks whose architectures are based on the same principles. • These new architectures will provide more flexibility for the support of services. • To enable generalized multimedia mobile services customers should be provided with personalized services across networks and between terminals, over mobile or fixed accesses whatever their location is. • This is the target. • In this paper, technical issues to overcome have been more specifically addressed in the case of IP transport. Special attention should be paid to fixed and mobile service convergence. • Many of these issues are currently under study in several standardization bodies and fora, to make this attractive future happens they should be consistently dealt with.

19. References "A Next generation architecture for the public network " ISS2000 TINA-C Network Resource Architecture, version 3.0 – Feb. 1997 TIPHON Network Architecture & reference configurations, DTS 02003 v0.0.1 – ETSI – March 1999 Multiservice Switching Forum Architecture, MSF99.074 – March 1999 Megaco Protocol Proposal Working draft, draft-IETF- megaco-protocol-01.txt – April 1999 Draft ITU-T Recommendation Q.BICC, Bearer Independent Call Control protocol definition RFC 2543 SIP : Session Initiation Protocol RFC 3015 Megaco Protocol v1.0 RFC 2002 IP mobility Support (for Ipv4) Universal Mobile Telecommunications System (UMTS); Virtual Home Environment (VHE) in the Integrated Services Digital Network, Evolved UMTS core network, ETSI EG 201 717. Universal Mobile Telecommunications System (UMTS); Service aspects; Virtual Home Environment (VHE), ETSI TR122 970, 3G TR 22.970. Eurescom Project P920, UMTS Network Aspects (http://www.eurescom.de/public/projects/P900-series/p920/P920.htm RFC 1633 Integrated Services in the Internet Architecture: an Overview RFC 2475: An Architecture for Differentiated Services RFC 3031: Multiprotocol Label Switching Architecture draft-ietf-mpls-diff-te-reqts-00: Requirements for support of Diff-Serv-aware MPLS Traffic Engineering RFC 1883: Internet Protocol Version 6 (IPv6)

20. Glossary ARF: Access to the Resources Function ASF: Access to the Services Function AP: Application Part BAS: Broadband Access Server CAP: Camel Application Part CS: Call Server CSCF: Call State Control Function DWDM: Dense Wavelength Division Multiplexing FA: Foreign Agent GGSN: Gateway GPRS Support Node GK: GateKeeper HA: Home Agent HSS: Home Subscriber Server IAP: Internet Access Provider IGP: Interior Gateway Protocol INAP: Intelligent Network Application Part ISDN: Integrated Services Digital Network ISP: Internet Service Provider LEX: Local EXchange LSP: Label Switched Path MG: Media Gateway MGC: Media Gateway Control MGCF: Media Gateway Control Function MPLS: MultiProtocol Label Switching MSC: Mobile service Switching Center NAS: Network Access Server NGN: Next Generation Network OTN : Optical Transport Network PHB: Per-Hop Behaviour POTS: Plain Old Telephone Service PDSN : Packet Data Serving Node PS: Proxy SIP PSTN Public Switched Telephony Network QoS : Quality of Service RC: Resources Control SC : Services Control SGSN: Serving GPRS Support Node SGW: Signalling Gateway UMTS: Universal Mobile Telecommunications System VHE: Virtual Home Environment VPN: Virtual Private Network