Deployment of the IMS at Telefónica Germany, fixed and mobile: why and how.

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1 Deployment of the IMS at Telefónica Germany, fixed and mobile: why and how. Workshop - Serviços de Comunicação de Próxima Geração Aveiro, 27 de Abril, Instituto de Telecomunicações Antonio Cuevas

2 Contents ICurrent IMS deployment at Telefónica Germany (DSL, life 2011) Why? How? And what? Plans for IMS for mvolte RCSe Conclusions and discussion

3 Current IMS deployment at Telefónica Germany DSL, about clients, life 2011

4 IMS was almost dead IMS is very complicated and plain IMS just offers voice As long as operators can keep offering voice over CS, no real need or business case to migrate to IMS IMS was almost dead. See next

5 History of Telefónica Germany is essential to understand the introduction of IMS a collection of Networks, created through various acquisitions National mobile network (German division of the mobile spin-off from British Telecom National wholesale Localloop-unbundling (LLU) fixed broadband network (German division of Spanish incumbent) Regional fixed telephony and broadband networks (German division of Telecom Italia) Telefónica purchased O 2 in 2006 Mobile + Broadband + Broadband + Fixed networks Telefónica Germany purchased HanseNet in 2010

6 Introduction of the IMS O 2, mobile only operator, never saw the need to introduce the IMS Telefónica Deutchland had a National wholesale Local-loop-unbundling (LLU) fixed broadband network No CS voice, only VoIP VoIP was subcontracted In 2006, Telefónica S.A. bought O 2 Create a German Integrated Operator Create own fixed VoIP platform No need to replace CS voice, there was not in fixed domain IMS was selected (2008) for replacing the subcontracted VoIP (fixed) Only in latter stages will the IMS replace CS voice (fixed and mobile)

7 O2 and its resellers The IMS deployed by o2 can be used by: O2 itself Resellers, having their own clients To efficiently manage the system, a reseller and a system level are available: Reseller: All have the same characteristics, including o2 System: top level, only 1 System. Managed by o2 but independent from the o2-reseller Reseller (Voice & LLU) System (o2) o2 Germany (Voice & LLU) Reseller (Voice & LLU) Subscriber Subscriber Subscriber Subscriber Subscriber Subscriber Subscriber Subscriber Subscriber SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num. SIP Account = Phone Num.

8 Interfaces to resellers Subscriber A Subscriber B Subscriber C Voice Service SIP Terminal Data Access - Internet Voice Service SIP Terminal Data Access - Internet Voice Service SIP Terminal Data Access - Internet Reseller CPE Mgmt CRM / Prov. 1st level Customer Care Billing Systems Customer Selfcare Portal Http(s), XML Http(s), XML File transfer Http(s), XML System Provider - Telefónica User Interfaces Options Electronic Interfaces / API Options Reseller Diagnosis Portal Reseller Report Delivery Reseller DSL Diagnosis Portal Reseller Self Care Portal (Admin) Customer Self Care Portal Reseller DSL LDAP Account Setup Portal Reseller Provisioning API Voice & DSL Ticket Interface Diagnosis API Billing Interface Subscriber CDR & Wholesale Bill Reseller / Subscr. Feature Control API Telefónica Supporting Systems 7

9 The Big Picture System Other Resellers HTTP(S) HTTP(S) API API Supporting Systems (Billing, Monitoring, Provisioning, etc.) End-User Provisioning RADIUS (Rf) Provisioning Diameter (Rf) Diameter (Rf) Provisioning VoIP-AS Platform IMS Core IMS C ore SIP (Mw) SIP (ISC) Media Server Media (Mb) HTTP(S) Distributed SBC Platform Media SIP Media SIP User Equipment (UE) Voice Class IV Infrastructure

10 A standard IMS SBC: P-CSCF (and IBCF) IMS Core: CSCF (+HSS) Supporting Systems: charging plus provisioning of users Standard interfaces (note RADIUS and not DIAMETER for the SBC Rf.) First for DSL network, not for mobile UMTS networks No PCRF (still QoS granted, see next) LTE+EPC mobile network in a next step Media does reach the P-CSCF (SBC)!!!! For lawful interception Resellers have an API to the support systems. Used, among others, to provision users. Support systems configure IMS core and AS Resellers and users have a web-based self-care interface for the telephony service provided by the AS

VoIP to the Home: the CPE Core is IMS-IP But how to

VoIP phones are very expensive The terminal (CPE)

phones No separate circuit switched network for the

QoS mechanisms so that IP data does not hamper VoIP

11 VoIP to the Home: the CPE Core is IMS-IP But how to bring VoIP to the home? VoIP phones are very expensive The terminal (CPE) Router + NAT Digitizes existing analog and ISDN phones No separate circuit switched network for the phone. QoS mechanisms so that IP data does not hamper VoIP Beispiel: 2 parallele Gespräche Egress Class IV Class V Ingress ATM Voice PVC CBR MAC 1 SBC SBCs SBC DSLAM ATM Data PVC UBR MAC 2

12 A robust network P-CSCF logically distributed: easy and efficient to achieve resiliency SBCs geographically distributed all over Germany But IMS core elements are not logically distributed: redundancy needed to achieve resiliency Two core sites: Hannover and Nürnberg Main engineering tasks: Load Distribution Detecting when nodes fail

13 Services and features MMTEL Services. Many offered, deployed a few: Call forwarding Voice2mail Call blocking / barring Call logs Parallel ringing Fax2mail AND: User Web UI FAC control

14 Services and features Multi-reseller Call capacity per subscriber (no to exceed DSL BW limit) announcements Dial plan, call categories operator / reseller barrings Destination number normalisation

15 Plans for IMS and mvolte

16 IP and VoIP in mobile networks are not new Release 99, from 3GPP

17 But there was a back door Voice could still use circuit switched

18 And operators were lazy and kept using circuit switched for voice

19 In LTE-EPC there is no back door To have voice, operators must use IP => ALL is IP LTE Go IP! Voice

20 Voice over IP means: Skype (not wanted, I imagine!) For operators, VoIP ó IMS Telefónica Germany has already deployed the IMS (great advantage). Voice over mobile LTE (mvolte) will use it Telefónica Germany will be the first OB in Telefónica to have mvolte and one of the first in the world.

21 LTE and Voice: Hop, Step and Jump Whitespot DSL Replacement ( fixed VoLTE ) Mobile Data With Circuit Switched Fallback (CSFB) Mobile Data With IMS-based Voice ( mobile VoLTE ) Fixed Subscriber Provisioning Mobile Subscriber Provisioning 20

22 mvolte Challenges From day 0 we could do voice calls over LTE (tests) IMS pre-prod and test enode B in München As we can also do voice calls over WiFi (tested from Boston, Sydney, Madrid, )!!! No Wonder: IMS uses IP and IP is agnostic to the layer 2 access technology. And LTE is just another radio access technology So that s it? Nothing to do??? NO!!!!! Actually, mvolte is one of the most challenging projects. Why? See next

Challenges and Pitfalls of mobile VoLTE An operator extending an IMS deployed for fixed services into the mobile domain faces some key questions.

IMS Core fixed xdsl (VoBB) 1. Subscriber data Mobile subscribers on to fixed HSS vs. evolution of HLR to be a mobile HSS 2.

23 Challenges and Pitfalls of mobile VoLTE An operator extending an IMS deployed for fixed services into the mobile domain faces some key questions. 3 Mobile IN Services Mobile voice core 2G/3G Mobile subscriber provisioning M LTE Fixed subscriber provisioning F Basic VoIP mobile converged IMS Core fixed xdsl (VoBB) 1. Subscriber data Mobile subscribers on to fixed HSS vs. evolution of HLR to be a mobile HSS 2. Consistent services Customer should not notice when he is upgraded to IMS-based mobile voice 3. Re-use vs. re-implementation of IN-based services 4. Availability of SRVCC in devices 22

24 Many possible scenarios to consider: When will Circuit Switched Fall Back (CSFB) be available (devices)? When will devices have IP-LTE voice capabilities? What to deploy in our network? Coexistence of 3G/2.5G and LTE And none of these scenarios is easy!!!

25 The challenges Two networks coexist. Coverage and mobility: What happens if a device is having a voice call over LTE Packet Switched (PS)-IP and moves to a 3G network where, even if PS is available for data, circuit switched (CS) must be used for voice? PS to CS handover! Not Simple!!! devices will not have two radios (too much batery power) Is the control of the call also transfered??

26 The challenges Two networks coexist. And the difference is not just the network technology (data transport, CS vs. IP) but also the service and user control. Where are calls and advanced services controlled?

27 The challenges Two networks coexist. And the difference is not just the network technology (data transport, CS vs. IP) but also the service and user control. What is the user database? HLR vs HSS Users will employ both networks, do they need to be stored in both databases?

28 ICS (IMS Centralised Services) IMS registration: MSC impersonates UE when UE in CS trigger: CS Location Update

29 ICS (IMS Centralised Services) MSC translates signaling: CS SS#7 => SIP MGW translates media non ICS UE A MSC Serv er MGW S-CSC F SCC AS UE B 1. CS call setup (B) 2. INVITE (B, SD P from CS-MGW) 3. INVITE (B, SDP from C S-MGW) 4. IN VITE (B, SDP from CS-MGW) 5. INVITE (B, SDP from C S-MGW) 6. Completion of Session Setup Procedures CS domain bearer IMS bearer

30 ICS (IMS Centralised Services) MSC translates signaling: CS SS#7 => SIP MGW translates media

31 VoLTE call and SRVCC LTE/EPC Mobile CS IMS

32 Handover to mobile CS (SRVCC) LTE/EPC Mobile CS IMS

33 UE Source E-UTRAN 1. Measurement reports Source MME MSC Server/ MGW Target MSC Target SGSN Target BSS S-GW / PDN GW IMS SRVCC detail: 2. Decision for HO 3. Handover Required 4. Bearer Splitting EPC and CS Mobile 5.PS to CS Req 6.Prep HO Req 8.Prep HO Resp 7. HO Request/Ack 9. Establish circuit 10. Initiation of Session Transfer (STN-SR or E-STN-SR) 15. HO from EUTRAN command 13.PS to CS Resp 14. Handover Command 11. Session transfer and Update remote end 12. Release of IMS access leg 16. UE tunes to GERAN 17. HO Detection 18. Suspend (see TS ) 18. Suspend Request / Response 18. Suspend 23a. TMSI Reallocation 22. PS to CS Complete/Ack 23b.UpdateLoc 24. Subscriber Location Report 20.SES (HO Complete) 21. ANSWER HSS/ HLR GMLC 19. HO Complete 22a. Bearer handling and suspension

34 User database HSS vs. HLR HSS was in introduced in 3G UMTS mobile networks HSS is the evolution of the HLR, the subscriber database in GSM mobile networks IMS CSCFs (Call Session Control Function, enhanced SIP proxies) are designed to Interact with HSS So what is the problem? Our 2.5G, 3G and, even, LTE/EPC keep using the HLR and IMS is NOT designed to interact with HLR, just with HSS!!

35 User database HSS vs. HLR So, we deployed the IMS in DSL with its own HSS And with its own provisioning mechanisms As a result, IMS-HSS Fixed World provisioning is independent from the mobile HLR provisioning (and billing and many other FAB topics)

36 User database HSS vs. HLR Most evident, academical and straight forward solution would be to migrate the mobile users from the HLR to the HSS But there are about 18M mobile HLR users and 300K HSS users High Risk! Still, the target is one consolidated database for HLR & HSS subscriber data and for mobile and fixed subscribers.

37 User database HSS vs. HLR Telefónica is planning to go for UDC Non-UDC Network UDC Network OSS, Self Care System Provisioning Interface NE OSS Provisioning Interface Ud Self Care system Provisioning FE NE-FE NE... UDR Ud Ud NE-FE... UE NE Ut self provisioning Network Interface NE NE Ud UE NE-FE Ut self provisioning Network Interface NE NE

38 RCSe

39 RCSe Nothing new: IM. One of the first integrated IM was in Portugal Needs to be different from existing IM: easy to use, universal, native on devices, etc. Uses the IMS Although RCS is standardised since long, it is only now, (as a reaction to WhatsApp), that operators will use it Presence was very complicated => RCSe

40 ENUM and IMS interconnect Currently, a global ENUM database is not yet implented ( DNS) IMS to IMS interconnection is very rare OK because IMS is only offering voice (mainly) and voice can be interconnected over the PSTN But, for IM, the PSTN can not be used: need of interconnection

41 Interacction with mvolte Terminals may have the RCSe APP but, still, use Circuit Switched for voice. Problem to be solved.

42 Conclusions and discussion

43 Conclusions and discussion Telefónica Germany initially introduced the IMS as a replacement of a standalone VoIP infrastructure. The long-term strategic goal is to use the IMS as a tool to converge different networks consolidation of networks: a strategy for IMS introduction is related to and dependent on convergence and evolution strategies in other parts of the network. In our experience, it is not easy to maintain a mid-term IMS evolution course while short-term disruptive influences cause Fear, Uncertainty and Doubt throughout the organisation. It is also not easy to maintain the interest of commercial units in the advanced features promised by IMS over a many-year transition period. Finally, a key factor for IMS is an organizational convergence, so that previously separated teams from fixed and mobile divisions (often from completely different companies) join forces to address the challenges that must be answered to enable technical convergence to take place.

44 Introduction to IMS (backup slides)

978-0470019061 The IMS Service Platform: A Solution for Next Generation Network Operators to Be More Than Bit Pipes

45 References The 3G IP Multimedia Subsystem (IMS): Merging the Internet and the Cellular Worlds Gonzalo Camarillo et al. John Wiley & Sons ISBN-13: The IMS: IP Multimedia Concepts and Services Miikka Poikselka Wiley ISBN-13: The IMS Service Platform: A Solution for Next Generation Network Operators to Be More Than Bit Pipes Antonio Cuevas, Jose I. Moreno, Pablo Vidales, Hans Einsiedler, IEEE Communications Magazine, ISSN August 2006.

Standardizes the UMTS mobile network: IMS was introduced in UMTS release 5 (June 2002) Keeps

46 IMS as a merge of two worlds IMS is a SIP platform running and interacting with a UMTS mobile network. Thus merge of two worlds, IETF and 3GPP 3GPP. Standardizes the UMTS mobile network: IMS was introduced in UMTS release 5 (June 2002) Keeps evolving: Release 10 IETF. Internet standardization, among others SIP More than 40 RFCs dedicated to IMS, e.g. tailoring IETF protocols to IMS

47 IMS step by step Designed for 3G UMTS networks 3G UMTS network

48 IMS step by step But IMS works over IP (v6) IP Network GGSN Gateway from the UMTS network to other networks GGSN (or a IP router) 3G UMTS network Voice, Video

49 IMS step by step IMS is a infrastructure of SIP servers CSCF (SIP proxy and registrar) IP Network SIP signaling GGSN 3G UMTS network Voice, Video slide 5

50 IMS step by step that can interact with some UMTS nodes CSCF (SIP Proxy) SIP signaling GGSN 3G UMTS network Voice, Video

51 IMS step by step Media does not reach the IMS CSCF (SIP Proxy) SIP signaling GGSN 3G UMTS network Voice, Video

52 QoS in IMS: a scenario Two users want to setup a video call. The video flow needs 128 kbps, the audio one 16 kbps CSCF (SIP Proxy) SIP signaling Contains media flows requirements for the network (codecs, BW) GGSN 3G UMTS network Media Flows

53 QoS in IMS: a scenario The PCRF instructs the network to accommodate these flows CSCF (SIP Proxy) PCRF. Instructs the network to accommodate the media flows SIP signaling Contains media flows requirements for the network (codecs, BW) GGSN 3G UMTS network

54 QoS in IMS: a scenario Media flows traverse the network CSCF (SIP Proxy) PCRF. Instructs the network to accommodate the media flows SIP signaling Contains media flows requirements for the network (codecs, BW) GGSN 3G UMTS network Media Flows

55 Charging in IMS: a scenario Two users want to setup a video call. One is <18 years old, the other not. Time is 9 pm. CSCF (SIP Proxy) CSCF is aware of these details (video call duration, participants, start time.) SIP signaling GGSN 3G UMTS network Media Flows

56 Charging in IMS: a scenario video audio flows consume network resources CSCF (SIP Proxy) GGSN is aware of these details (bytes sent/ received ) GGSN 3G UMTS network Media Flows

57 Charging in IMS: a scenario UMTS CDF/CGF gathers and correlates both data CSCF (SIP Proxy) CDF/ CGF GGSN 3G UMTS network Media Flows

58 Authe. and Autho. in IMS Depends on 3G user control. SIP signaling proceeds only after contacting the HSS S-CSCF SIP Signaling HSS GGSN 3G UMTS network

59 Abbreviations SIP: session initiation protocol. Used to negotiate (multimedia) sessions e.g. codecs to employ CSCF: Call Session Control Function. A SIP server / registrar HSS: Home Subscriber Service. User data base of the mobile operator CDF/CGF: Charging Data/Gateway function. Collects accounting data from several entities GGSN: Gateway GPRS Support Node. A router to other networks (IP, Internet) PCRF: Policy and charging rules data function. Link between the codecs and BW negotiation via CSCF and the BW reservation in PCEF PCEF: Policy and Charging Enforcement Function. Enforces the PCRF decision. A router in IP NGN, a GGSN in UMTS, PDN-GW in LTE CSCF (SIP Proxy and registrar) SIP signaling PCRF HSS CDF/ CGF GGSN 3G UMTS network Voice, Video

Improvement of VoLTE Domain HO with Operators Vision

TS-A3 (Technical Session): Mobile Access and Network - #4 Improvement of VoLTE Domain HO with Operators Vision NW Strategy Group, Global Standardization Team Network Development Department NTT DOCOMO R&D