Quality of Service for Next Generation Networks Hui-Lan Lu, Ph.D. Rapporteur, ITU-T Q4/13
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ITU-T / ATIS Workshop “Next Generation Network Technology and Standardization” Las Vegas, 19-20 March 2006 Quality of Service for Next Generation Networks Hui-Lan Lu, Ph.D. Rapporteur, ITU-T Q4/13 Bell Labs, Lucent Technologies ITU-T Outline Complexity of NGN QoS Key QoS topics under study in ITU-T Active NGN QoS work items in Q4/13 Resource and admission control Inter-domain performance measurement and management Summary ITU-T 2 ITU-T / ATIS Workshop “Next Generation Network Technology and Standardization“ Las Vegas, 19-20 March 2006 Complexity of NGN QoS NGN 802.xx Access Cable Domain 1 IntServ Domain 2 Domain 3 DiffServ MPLS-TE Domain 4 Over-Prov xDSL Multi-Service Packet Transport 2G/3G Wireless User-perceived QoS is end-to-end (cf. E.800) NGN QoS is complex because • NGN applications have diverse performance needs • IP is not designed for consistent application performance — Various mechanisms have been introduced with specific applicability • Diversity in an end-to-end path is common owing to — Different levels of QoS support in endpoints — Varying types of QoS support in the transport — Multiple provider domains Effective management of resource contention is an important aspect of NGN QoS support ITU-T 3 ITU-T / ATIS Workshop “Next Generation Network Technology and Standardization“ Las Vegas, 19-20 March 2006 Key QoS Topics under Study in ITU Performance objectives, including • Network performance classes • Network performance allocation Dynamic QoS controls, including • • • • • Signaling of performance requirements Resource and admission control Interworking of QoS mechanisms Inter-domain considerations Frameworks and guidelines Performance measurement and management Performance assessment SG 12 ATIS has been a key contributor ITU-T 4 SG 12 SG 16 FGNGN SG 11 SG 13 FGNGN SG 4 SG 12 SG 13 FGNGN A major goal is to develop an end-to-end QoS solution that allows incremental deployment ITU-T / ATIS Workshop “Next Generation Network Technology and Standardization“ Las Vegas, 19-20 March 2006 Active NGN QoS Work Items in Q.4/13 Requirements and architecture for resource and admission control in NGN (Y.racf) A QoS control architecture for Ethernet-based IP access networks (Y.123.qos) A QoS architecture for Ethernet networks (Y.enet) Performance measurement and management for NGN (Y.pmm) Requirements and framework for end-to-end QoS support in NGN (Y.e2eqos.1) Priority classification for IP networks and services Requirements for flow-aware transport in NGN Notes: 1. Q.4/13 has inherited most of the FGNGN QoS work as highlighted. 2. Y.pmm is worked jointly with Q17/12, which also is the home of Y.1541 and the FGNGN follow-up work on network performance (including Y.NGN.NHNperf and G.fepo). 3. SG 11 has approved the FGNGN output on IP QoS signalling requirements as Q-Series Supplement 51. ITU-T 5 ITU-T / ATIS Workshop “Next Generation Network Technology and Standardization“ Las Vegas, 19-20 March 2006 Schematic View of ITU-T NGN Framework Architecture Cf. Y.FRA (TD133-WP2/13, 01/2006) 3rd Party Applications Management Functions ANI Control Media Management Application/Service Functions Service User Service User Profiles Profiles Service stratum Transport User Profiles Service Control Functions Network Attachment Control Functions Resource & Admission Control Functions Transport Control Functions End-User Functions Other Networks Transport Functions UNI NNI Transport stratum Resource and Admission Control Functions (RACF) Preserve the separation of services and transport Bridge services and transport to enable dynamic application-driven support for performance assurance and network border control ITU-T 6 ITU-T / ATIS Workshop “Next Generation Network Technology and Standardization“ Las Vegas, 19-20 March 2006 ITU-T RACF Architecture Service Control Functions (part of IMS or else) Service Stratum Rp Network Attachment Control Functions intraintradomain interinterdomain Rd Transport Resource Control Function Ru Policy Decision Function Rt Ri RACF Other NGNs Rs Transport Stratum Rc Rn Transport Enforcement Function Rw Policy Enforcement Function Interconnection Functions Transport Functions Policy Decision Function service facing, transport independent Transport Resource Control Function service independent, transport dependent, possibly network-segment specific Policy Enforcement Function typically part of border transport elements ITU-T 7 RACF augments native transport QoS support 9 Preempting transport congestion at the service control layer All applications (VoIP, IPTV, etc.) involving network-based control can make use of RACF via Rs ITU-T / ATIS Workshop “Next Generation Network Technology and Standardization“ Las Vegas, 19-20 March 2006 Roles of RACF and Related Entities Policy Decision Function Makes the overall admission decision based on policy and resource availability Applies resource controls to the transport for bandwidth reservation, packet marking, gating, NAPT, etc. Transport Resource Control Function Tracks transport resource usage and network topology Checks resource availability Applies L2 resource controls to the transport Policy Enforcement Function Enforces controls applied by PDF Provides resource information to TRCF ITU-T 8 Overall, RACF supports Relative and absolute QoS, including priority Endpoints of varied QoS control capabilities Push and pull models for policy installation Multiple transaction models for resource requests Various resource management methods based on accounting, measurement and reservation Existing and emerging transport QoS mechanisms ITU-T / ATIS Workshop “Next Generation Network Technology and Standardization“ Las Vegas, 19-20 March 2006 A Configuration Example Service Control Functions Service Control Functions Service Stratum Rs Transport Stratum Rs Rt Rp Rt Ru TRCF Rw Customer Premises Network Ri PDF Rc PEF TRCF Rw PEF Access Network The Policy Enforcement Function can reside in the Gateway GPRS Support Node (GGSN) Packet Data Serving Node (PDSN) Session Border Controller (S/BC) Rw Rc Rw PEF PEF Core Network Broadband Remote Access Server (BRAS) Cable Modem Termination System (CMTS) Border gateway Y.123.qos and Y.enet under way apply RACF to Ethernet-based IP access networks and Ethernet-based NGN, respectively ITU-T 9 Other NGNs Ri PDF Network Attachment Control Functions Rd ITU-T / ATIS Workshop “Next Generation Network Technology and Standardization“ Las Vegas, 19-20 March 2006 Inter-Domain Performance Measurement and Management (Y.pmm) Service Provider A Performance Reporting System Collection Platforms Control, Reports Service Provider B Summary reports, measurement requests Config, Reports, Policing info Probes, Policing info Control, Reports Config, Reports, Policing info Delay/Loss Probes Probes, Policing info Performance Reporting System Collection Platforms Measurement Platforms PE/CE PE/CE Definitions of attributes to be measured — Mean delay, delay variation, packet loss, path unavailability (cf. Y.1541) How attributes are measured, e.g., — Active or passive measurement (cf. Y.1711 and Y.1731) — Active probes tailored to Y.1541 QoS classes — Clock synchronization to Coordinated Universal Time through GPS or the like Management requirements for discovery, inter-PRS communication, etc. ITU-T 10 ITU-T / ATIS Workshop “Next Generation Network Technology and Standardization“ Las Vegas, 19-20 March 2006 Summary NGN QoS has been an active area under study in ITU with active ATIS’s involvement • A key goal is to develop an end-to-end QoS solution that allows incremental deployment Q.4/13 has several related work items ongoing (in collaboration with SGs 4, 11 and 12 as appropriate), including • Y.racf (targeted for consent in July), which outlines an approach to dynamic application-driven resource and admission control to support performance assurance and network border control — Related protocols are under development in Q5/11 — Draft Recommendations Y.123.qos and Y.enet apply RACF to specific environments • Y.pmm, which outlines a basic framework for inter-domain performance measurement and management • QoS and priority, which has been recently initiated to further support emergency telecommunications services Cooperation among related standards efforts across SDOs is critical to the development of consistent and interoperable mechanisms, which are essential for effecting QoS end-to-end ITU-T 11 ITU-T / ATIS Workshop “Next Generation Network Technology and Standardization“ Las Vegas, 19-20 March 2006
