Deploying Media Probes in Evolving VoIP Networks

Transcription

1 Deploying Media Probes in Evolving VoIP Networks Dave Gladwin Presentation Template V4.00 Nov-05

2 Agenda! Convergence of Fixed and Mobile services are driving networks towards IMS based architectures in order to offer ubiquitous services.! This session looks at:! How networks are evolving to deliver new services.! The requirements placed on the networks to deliver LI! A brief overview of a typical VoIP LI architecture! Pulling it all together 2

3 Next Generation Networks - Observations! Tier 2s lead the way with tactical IMS deployments! Tier 1s generally playing catch up! Most VoIP plays are opportunistic/tactical today! NGN is more than VoIP! Consumer, Business and Enterprise focus! Many different forms of NGN! PSTN replacement 21CN! New service overlay PoC! Multimedia Video services! Fixed Mobile Convergence! IPTV! All of this means network evolution and IMS 3

4 Why IMS?! PSTN -> IMS is a logical migration step to provide new services! PSTNs which have already migrated to NGNs may look at reducing further CAPEX by migrating to an IMS-like core! IMS provides the glue between services and networks! It aims to deliver any service to any device over any network! Designed to allow rapid prototyping and deployment of services! Mobile Service Providers:! IMS was created to fulfil need for feature rich services! Converged service to business and residential! Wireline Service Providers:! Long term PSTN replacement programs! Must innovate to regenerate Wireline revenues! Add value to existing services! Move into new markets via convergence! Reduce Opex 4

5 The Evolution Path! Today VoIP is driving deployments! Often overlaid onto current IP data networks! All I need is a Softswitch?! Need to overcome some issues to achieve this! Connectivity! Quality! Security! Resilience 5

6 How have networks evolved? Softswitch SBC Signalling Media Core IP Network SBC NAT Traversal Session Policing Peer IP Network Topology Hiding Security 6

7 How have SBCs evolved? Integrated SBC Distributed SBC Softswitch BC SBC Sig Core IP Network nal ling BG BG BG 7 Med ia Peer IP Network

8 TISPAN Architecture Interconnect Signalling BC A-BGF Access SBC Interconnect Media BG 8

9 Integrated Integrated and Distributed SBC Architectures SIP Signalling SIP Signalling RTP media RTP m BC Distributed CA/SS/P-CSCF SBC SIP Signalling RT Pm edi a edia CA/SS/P-CSCF SIP Signalling H.248/Megaco H.248/Megaco SBC Session Border Controller BC Border Controller BG Border Gateway 9 BG RTP media BGF

10 VoIP Peering The Traditional Interconnect Model Regionalised SBC for signalling and media Softswitch / Call Agent Single SBC per region National IP Backbone SBC Southern Region Carrier A 10 SBC Northern Region Carrier B In-region Policies Media Steering in-region by SBC Intelligence closer to the edge Network architecture for Softswitch or Call Agent Interworking and Integration SBC Western Region Carrier C

11 VoIP Peering The distributed Interconnect model With centralised SBC for Signalling and distributed Media Softswitch / Call Agent National IP Backbone BCF Centralised Border Controller Single point of Policy Media Steering in-region by BGF to optimise RTD and network utilisation No replication of functionality Simplified network architecture for Softswitch or Call Agent Southern Region Northern Region BGF BGF BGF Carrier B Carrier C Carrier A 11 Western Region

12 Summary of LI landscape! Separate legal frameworks for most countries! Technical standards mostly relate to interfaces with much common ground! But most have some common requirements! Legally sanctioned official access to private communications! Can only be enabled with a legal warrant! Required functionality in modern telecoms equipment! Must provide transparent interception of specified traffic only! Targeted user must not be aware of interception! Other users must not be affected during interception 12

13 Getting Access to Signalling and Media! Intercept model assumes communications nodes can access signalling and media! In VoIP Networks they are separated often in different devices! Session control devices are already aware of signalling media relationships 13

14 Split between signalling and voice Traffic Data (Signalling) Communications Data (Media) NB in VoIP networks the Media and Signalling can take different paths NB Anti-tomboning may mean the media is not even in the same network as signalling 14

15 PacketCable Architecture Conceptual! PacketCable surveillance model - CALEA compliant! The same basic arrangements as ETSI 15

16 ETSI Architecture Conceptual! General Networks architecture for Intercept (ETSI) 16

17 LI Elements Administration Function! The Network Operator implements interception warrants via the Administration Function! The Administration Function manages the Intercept Function in the network nodes and the Media Functions 17

18 LI Elements Handover Interfaces! Three Handover Interfaces link the Public and LEA networks! HI1 Administration input! HI2 IRI delivery to Law Enforcement Monitoring Facility (LEMF)! HI3 CC delivery to LEMF 18

19 LI Elements Interception Function! Internal Intercept Functions (IIF) implemented in network nodes! Warrant may require IRI, CC or both 19

20 LI Elements Mediation Function! Mediation Functions convert deliver Intercept Information to the LEMF over standard interfaces, HI2, and HI3! Delivery may be IRI, CC or both 20

21 Architecture - Physical! Intercept Functions present on both signalling (IRI) and media (CC) elements! Management Unit runs the Administration Function, performs provisioning and monitoring.! Handover Unit runs the Mediation Function, performs buffering, validation and countryspecific delivery.! Both units backed up by warm standbys with automatic replication of data between peers. 21

22 Central Softswitch and Distributed Gateways Softswitch BG BG BG Target Provisioning Signalling Media IRI (HI1) CC (HI2) 22 ADMF/ MF LEMF

23 Central Controller and Distributed Gateways Softswitch ADMF/ MF BC BG BG BG Target Provisioning Signalling Media IRI (HI1) CC (HI2) 23 LEMF

24 Conclusion! Networks will continue to evolve to support Multimedia services! Separated signalling and multiple media paths will become prevalent! Distributed (edge) elements Gateways and Controllers are strategically located to facilitate target acquisition! A flexible approach is essential to allow natural network evolution whilst still meeting both commercial and regulatory needs 24

25 Thank You Questions Lawful Intercept White Paper: Presentation Template V4.00 Nov-05