MWIF Gap Analysis MWIF BOD Led Core Network Standard Initiative Nov. 13 th, 2001
Contents – Overview of 3 GPP/3 GPP 2/MWIF NRAs – Brief comparison of 3 GPP and 3 GPP 2 legacy components – Comparison of functionality of 3 GPP/3 GPP 2/MWIF Core Network Reference Architectures – Summary of Gaps
*this diagram has been modified from that in the specification for illustrative purposes. Any inaccuracies are unintentional 3 GPP Network Reference Architecture – R 5* Applications & Services IP Multimedia Subsystem SCP Legacy mobile signalling Network CAP Mm CSCF Mw Mg CSCF Mi Cx Ms Mr MGCF Mj Mc T-SGW BGCF Gi MRF PSTN/ Legacy/External MGW UMS R-SGW Multimedia IP Networks HSS Mb Gr Gi 3 G-HLR Gc CS Domain Gi G-MSC Server Gn 3 G-SGSN 3 G-HLR Emergency Services Network PS Domain 3 G-GGSN Lg Gi GMLC RAN Signaling only User Data and Signaling BSS/ GERAN UTRAN MT TE Fundamental requirement to support evolution from current GSM Circuit switched and GPRS Packet switched network in support Of an IP Multimedia Domain for IP based services support for UMTS. MSC Server Application Service Control Transport Multimedia IP Networks
3 GPP 2 All IP Network Reference Architecture Application Databases EIR DSI Sub Service Application Poli 2 5 Service 6 Subscription Qo. S Manager 8 10 Control 1 Position Server Transport CDMA selection for Packet Switch support was much more Internet friendly than the GSM GPRS choice. Thus, the CDMA All IP architecture (aka 3 GPP 2) defines more discrete IP based functional elements. Signaling-Control Bearer Radio 9 4 AAA 20 21 18 Position Determining Entity 19 Access Net. BTS BSC + PCF 31 Access Gateway 16 Session 24 17 29 FA/ Attendant Media Gateway Control 30 34 33 Media PSTN Gateway 37 22 Mobile IP 43 Home 41 Agent 26 25 27 Media Resource 32 Function 38 40 42 Border 44 Router 45 47 MS Trunk Signaling Gateway 12 23 Core Qo. S 3 Manager 28 MAP 41 & GSM 14 Gateway 36 35 MM Other Access Networks 13 Signaling Capability Gateway Control Manager 15 Roaming 11 Network 39 48 Legacy MS Domain Support 46 IP Network
MWIF NRA (MTR-004 v 2. 0) Resource Directory Services Application Location Server Global Name Server Geographic Location Manager Application Functional Entities Policy Repository Transport Core Network Application(s) Service Discovery Server Authentication Server Multimedia Resource Controller Session Proxy Home IP Address Manager Accounting Server Resource Manager Session Anchor Multimedia Resource Function Mobile Attendant Access Gateway i Authorization Server Communications Session Manager (CSM) Home Mobility Manager MWIF’s objective was to define an Access Independent Core Network architecture based on IP. 3 rd Party Application(s) AAA Functional Entities Service Control Profile Server l IP Address Manager Access Transport Gateway Media Gateway Controller Transport Gateway Functional Entities IP Gateway Signaling Gateway Media Gateway Bearer Access Network Signaling-Control Terminal UIM Intranet INTERNET Enterprise PSTN MAP 41 & GSM
Functional Comparison of 3 GPP & 3 GPP 2 -Legacy Functional Element 3 GPP 2 (GSM evolved) (CDMA evolved) Circuit Switch Call Control MSC, GMSC Functionally equivalent but different signaling protocols are used. Packet Switch Data SGSN/ GGSN PDSN, Mobile IP Home Agent 3 GPP mobility is handled by the PS domain (and does not support heterogeneous access). 3 GPP 2 mobility is handled by the PDSN and the Mobile IP Home Agent User Subscription Data HLR Different formats for data Different signalling interfaces to access the data. Mobile Station UE MS GSM/UMTS supports separation of the subscriber (SIM) from the TE. UMTS - comprised of the Mobile Terminal (MT) and Terminal equipment. . CDMA - supports separation of the subscriber (SIM) from the TE. Deltas
Functional Comparison of 3 GPP-3 GPP 2 -MWIF Functional Element 3 GPP (R 5) 3 GPP 2 (All IP) MWIF Deltas Access Gateway GGSN Access Gateway (FA/Attendant) Access Gateway (Mobility Attendant, IP Address Manager, Access Transport GW) 3 GPP GGSN is the Access Gateway from the perspective of the IM Subsystem. From the perspective of the RAN, the SGSN can be viewed as the Access Gateway. IP Address Manager and Access Transport GW are inherent functions of GGSN and 3 GPP 2 Access GW. Mobility Management SGSN/ GGSN Mobile IP Home Agent, Access Gateway Mobility manager, Access gateway 3 GPP mobility is handled by the PS domain (and does not support heterogeneous access). 3 GPP 2 and MWIF mobility is based on IETF Mobile IP model. Media Gateway Control BGCF, MGCF L-SCM, MGCF Session Anchor, MGC L-SCM of 3 GPP 2 approximates the functionality of the 3 GPP BGCF, but is not yet fully defined. Media Gateway MGW Media Gateway None. All should be based upon MEGACO. Signaling gateway T-SGW Trunk Signaling gateway None, although, local signaling variants would require different “flavors” of Signaling Gateway. Legacy Roaming R-SGW Roaming signaling gateway Signaling Gateway 3 GPP/3 GPP 2 R-SGWs are functionally equivalent, however, protocols are different. MWIF does not have a specific functional element to handle the signaling for legacy roaming, this functionality is deemed to be part of the Signaling Gateway.
Functional Comparison of 3 GPP-3 GPP 2 -MWIF Functional Element 3 GPP 2 MWIF Deltas Multimedia Resource Functions (Conf/Annc Servers) MRF Media resource Function MRC, Media Resource Function MWIF specifies a separate controller from the Media Resource Function. 3 GPP specifies the MRC as part of the MRF. AAA HSS, S-CSCF AAA 3 GPP has defined the Cx interface to be DIAMETER, thus an AAA infrastructure is assumed to be part of the architecture, however, the functionality is distributed amongst the entities, thus it’s not entirely clear that AAA infrastructure is deemed to be logically separate from functions such as Session Management or Directory Services. Qo. S PCF (part of CSCF), GGSN Core & subscription Qo. S managers, Access Gateway, Border Router Resource manager, Access Gateway All similar in that the Qo. S Policy Enforcement is done by Access Gateway and Policy data is part of the Database. Interfaces and control flow slightly different. Location of PDP different, but logically equivalent to the IETF model. Qo. S Policy data is in the databases, auth models are different. Geographic Position GMLC, SMLC Position Server, Position Determining Equipment Geographic Location Manager 3 GPP GMLC/SMLC are access specific and used for support of emergency services. This information is not intended to be generic geographic location information. MWIF assumes Geo Location stored in the Location Server 3 GPP 2 defines a Position Server outside of the Databases HSS Databases Directory services Functionally equivalent. Each architecture has a different logical separation of data.
Functional Comparison of 3 GPP-3 GPP 2 MWIF Functional Element 3 GPP 2 MWIF Deltas Session Management CSCF (S-CSCF, P-CSCF, ICSCF) SCM (S-SCM, I-SCM, E-SCM, P-SCM, LSCM) CSM, Session Proxy, S-CSCF, S-SCM and CSM functionally equivalent P-CSCF, P-SCM and Session Proxy equivalent I-CSCF and I-SCM appear to be functionally equivalent (THIG? ). This role in MWIF would be partly subsumed by the Session Proxy (Interrogating role). The Topology hiding part could be done with a Firewall (or a more specialized middlebox). Services S-CSCF, Applications & Services S-SCM, NCGW CSM For all the architectures, there will be some services inherent to the Session Managers (SCSCF, S-SCM, and CSM). Due to the different interfaces, MWIF supports services via the interfaces from the CSM to the AAA entities, Policy, Directory Services, thus the infrastructure is inherently “Service” Oriented. 3 GPP 2 NCGW role is between Application and Session Mgmt and is more a central point of control. It plays a role in Application Authorization. It is based on the 3 GPP OSA gateway. Applications & Services Service application Core Network applications, 3 rd party applications Theoretically, there should be none, however, in the end requirements may result in some differences. There may also be differences in the level of programmability for the applications. Service Discovery - - Discovery Server MWIF defines separate element for determining service availability. 3 GPP restricts the user to the selection of the SCSCF. (may support this function in R 6).
Summary of Gaps • Areas with largest gaps: – Legacy support – support for this in a generic manner isn’t possible due to differences in signaling mechanisms, databases, etc. Requires specific protocol inter-working elements. – Mobility support – in order to support heterogeneous access across the different networks (and with additional flavors of access networks), an access independent Mobility mechanism (e. g. IETF Mobile IP based) would be needed to be supported by 3 GPP.
Summary of the Gaps • Areas with gaps that could prove significant: – The degree to which 3 GPP and 3 GPP 2 deviate or require additions to the IETF SIP protocol could further increase the delta between the 2 networks. – Common mechanism for Geographic Location across the networks (access independent) for support of such things as Emergency calls. – Subtle differences in functional elements like MRF increases the likelihood of services and applications NOT being consistent across the platforms. – Lack of a more formalized AAA infrastructure in the IM Subsystem for 3 GPP increases the likelihood that this functionality is not clearly separated from Session Control, Databases (and even areas like Service Authorization).
Summary of the Gaps • Areas with workable gaps: – Qo. S mechanisms and control flow in an access independent manner where possible (with alignment to IETF mechanisms).
Conclusion and next steps – Create a set of operation and business requirements from MWIF’s gap analysis for harmonization – Utilize requirements to formally and informally influence standardization – Initial activities will include: • Provide operation and business requirements for OHG’s harmonization meeting in 1 Q 02 • MWIF operators will work behind the scenes to proactively garner support for the requirements – Develop realistic incremental steps to meet harmonization requirements