International Telecommunication Union Workshop on End-to-End Quality of Service.What is it? How do we get it? Geneva, 1-3 October 2003 ITU-T Recs. Y.1541 and Y.1221 A Basis for IP Network QoS Control and Traffic Management Neal Seitz U.S. Department of Commerce, NTIA/ITS

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Y.1541 / Y.1221 Roles o 3 Steps in achieving IP network QoS control Quantify user/application QoS needs (and associated traffic characteristics) Communicate the QoS needs and traffic characteristics into and among networks Implement IP network QoS mechanisms supporting the requested QoS/traffic levels o Y.1541: QoS classes quantify user application needs in terms of IP network performance o Y.1221: traffic contract complements QoS class by describing flow characteristics/limits The two Recommendations together specify the key data for IP network QoS signalling.

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Y.1541 Quantifying User QoS Needs in IP Terms o Relate subjective QoS descriptions … Audio: staticky, warbley, muffled, clipped Video: blurry, jerky, blocky, busy, blotchy o With IP network/terminal attributes … Packet transfer delay, delay variation Packet loss and error ratios Capture results in a set of QoS classes that … Categorize major IP user application needs Can be communicated via signaling Can be supported with IP QoS mechanisms.

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Y.1541 Mapping Function Voice Video Data Call Control Customer-Perceived QoS Subjective Descriptors Objective Estimators Voice Video Data Call Control Network QoS Control Network Control Network Bearer Network Bearer Network Bearer Network Control Network Terminal NI to NI QoS (Y.1541) Speed, Accuracy, Dependability Service Availability (Future) NI

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Table 1/Y IP QoS Class Definitions and NP Objectives Network Performance Parameter Nature of Network Performance Objective Class 0 Class 1 Class 2 Class 3 Class 4 Class 5 IPTD Upper bound on the mean IPTD 100 ms 400 ms 100 ms 400 ms 1 sU IPDV Upper bound on the quantile of IPTD minus the minimum IPTD 50 ms UUUU IPLR Upper bound on the packet loss probability 1*10 -3 U IPERUpper bound1*10 -4 U

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Table 2/Y.1541 Guidance for IP QoS Classes QoS Class Applications (Examples)Node Mechanisms Network Techniques 0 Real-Time, Jitter Sensitive, High Interaction (VoIP, VTC) Separate Queue with Preferential Servicing, Traffic Grooming Constrained Routing/Distance 1 Real-Time, Jitter Sensitive, Interactive (VoIP, VTC) Less Constrained Routing/ Distance 2 Transaction Data, Highly Interactive (Signalling) Separate Queue, Drop Priority Constrained Routing/Distance 3 Transaction Data, Interactive Less Constrained Routing/ Distance 4 Low Loss Only (Short Transactions, Bulk Data, Video Streaming) Long Queue, Drop Priority Any Route/Path 5 Traditional Applications of Default IP Networks Separate Queue (Lowest Priority) Any Route/Path

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Attributes of the Y.1541 IP Network QoS Classes o Encompass major IP application categories o Are relatable to IP network QoS mechanisms o Are achievable in realistic implementations o Are verifiable at jurisdictional boundaries (TE/IWF can measure QoS, ensure values met) o Can support QoS negotiation among systems Meet need for a lingua franca to support QoS interworking

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Y.1221: Traffic and Congestion Control in IP Based Networks Traffic Contract Dedicated BW Statistical BW Best Effort Max Pkt Size Token Bucket –Rate (Rp, Rs) –Size (Bp, Bs) (Y.1541) IP Transfer Capability Traffic Descriptor QoS Class Traffic Contract defines conditions under which specified QoS levels can be met.

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Possible Relationships Between Y.1541 Classes and Y.1221 TCs (for the Diffserv QoS Mechanism) Y.1221 transfer capability Associated DiffServ PHB IP QoS classRemarks Best Effort (BE) Default QoS Class 5 (Unspecified) A legacy IP service, when operated on a lightly loaded network, may achieve a good level of IP QoS. Statistical Bandwidth* (Modified to Limit Delay) AF QoS Classes 2,3,4 The IPLR objective applies only to the IP packets in the higher priority levels of each AF class; the IPTD objective applies to all packets. Dedicated Bandwidth (DBW) EF QoS Classes 0 and 1 – * A modified DBW capability could also be used.

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Signaling QoS/Flow Requests: SG 13 Proposed Requirements o Allow requesting user to specify QoS class o Allow user specification of traffic descriptor o Allow ex(im)plicit definition of common apps o Support basic IP packet transport: QoS, traffic o Let user decide to take lower QoS or clear call o Implement dynamic (not static) QoS allocation o Support QoS mapping among diverse networks o Allow QoS choices for call control, availability (future) Signal Y.1541, Y.1221 values ex(im)plicitly

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Example QoS Signaling Exchange Terminal Control Network Control Network Bearer Network Bearer Network Bearer Network Control Network Customer Service Notification, Including Call Characteristics Signaling Message (with QoS/Flow RQ) Translation of Service RQ to Y.1541/Y.1221 QoS/Flow RQ Translation of Y.1541/Y.1221 QoS/Flow RQ to Service RQ Customer Service Request, Including Call Characteristics

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Example QoS Signaling Exchange Terminal Customer Service Confirmation, Including Call Characteristics Control Network Control Network Bearer Network Bearer Network Bearer Network Control Network Service Response, Possibly Including New Call Characteristics Translation of Y.1541/Y.1221 QoS/Flow RSP to Service RSP Translation of Service RSP to Y.1541/Y.1221 QoS/Flow RSP Signaling Message (with QoS/Flow RSP)

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? QoS Signaling Completed -- Flow Established Terminal Control Network Control Network Bearer Network Bearer Network Bearer Network Control Network Customer Data (QoS and flow characteristics consistent with Y.1541, Y.1221)

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Figure 1/Y.qosar – Architectural Framework for QoS Support Control Plane Data Plane Management Plane QOS Routing Admission Control Resource Reservation Buffer Management Congestion Avoidance Packet Marking Queuing & Scheduling Traffic Shaping Traffic Policing Traffic Classification Metering Service Level Agreement Policy Service Restoration Policy

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Figure 2/Y.qosar – A Comprehensive QoS Approach Based on Resource Isolation and Service Requests (Under Study) Bearer Layer Bearer Control Layer Service Control Layer Edge Router Transit Router Core Router LSP Service Control Server Bearer Resource Manager

ITU-T October 2003 Workshop on End-to-End Quality of Service. What is it? How do we get it? Synopsis and Next Steps Synopsis o Signaling QoS (and flow) parameters will be essential to successful IP/PSTN convergence o Y.1541 QoS classes, Y.1221 traffic contracts define the essential content to be signalled Next Steps for Standards Organizations o Complete/coordinate signalling requirements o Implement requirements in specific protocols o Develop QoS signalling interworking solution Coordinated effort involving ITU-T, ITU-R, IETF, and other stakeholders is warranted