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Recommendation Y.1541 QoS Classes: A Basis for IP Network QoS Control -- Neal Seitz, Chair SG 13/WP 4. IP QoS control: key to IP/PSTN network convergence Y.1541: “Step 1” in achieving QoS enabled IP networks Quantify user/application needs via standard IP QoS classes
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Recommendation Y.1541 QoS Classes:A Basis for IP Network QoS Control -- Neal Seitz, Chair SG 13/WP 4 • IP QoS control: key to IP/PSTN network convergence • Y.1541: “Step 1” in achieving QoS enabled IP networks • Quantify user/application needs via standard IP QoS classes • Signal the standardized QoS classes to and among networks • Realize the QoS classes using network QoS mechanisms • Standardize QoS signaling protocols using Y.1541
Importance of IP Network QoS Control VoIP/MM needs are clear, but too demanding for today’s IP • Rec. G.114 -- “Mouth-to-ear” signal transmission time • Rec. G.109 -- Categories of speech transmission quality • Rec. G.1010 -- End-user multimedia QoS categories IP QoS solutions exist, but are not widely implemented • RSVP/intserv -- Controlled load, guaranteed services • DIFFSERV -- EF, AF per hop behaviors (PHBs) • MPLS, MPλS -- Traffic engineering, CoS, QoS, VPNs • Linking user application needs with network QoS mechanisms would advance PSTN/IP convergence
Achieving QoS in IP Networks -- Step 1: Quantify User/Application Needs in IP Terms Relate subjective descriptions of QoS imperfections … • Audio: “staticky, warbley, muffled, clipped” • Video: “blurry, jerky, blocky, busy, blotchy” With measurable IP network/terminal characteristics … • Packet loss, delay, delay variation, error • Signal compression artifacts, capacity limits • Capture results in a limited set of QoS classes … • Categorize the major IP user application needs • Can be communicated among networks via signaling • Can be implemented with existing IP QoS mechanisms
Y.1541 “Mapping” Function Voice Video Data Call Control Customer-Perceived QoS Subjective Descriptors Objective Estimators Voice Video Data Call Control Terminal-to-Terminal QoS (Y.1541) Speed, Accuracy, Dependability Service Availability (Future) Terminal Terminal Network QoS Network QoS Network QoS Control Network Control Network Control Network Bearer Network Bearer Network Bearer Network
Table 1/Y.1541 -- IP QoS Class Definitions and Network Performance Objectives
Attributes of the Y.1541 IP Network QoS Classes • Encompass the major IP user application categories • Are relatable to practical IP network QoS mechanisms • Can be achieved in realistic network implementations • Are verifiable at jurisdictional network boundaries (TE/IWF can measure QoS to ensure values are met) • Can support QoS negotiation among networks • Meet the need for a lingua franca to support QoS interworking
Achieving QoS in IP Networks -- Step 2: Signal QoS Classes to/among Networks • Allow the user requesting service to specify QoS class • Allow specification of traffic descriptor (Rec. Y.1221) • Support requests for basic IP transport: QoS, traffic • Allow well-defined apps to be identified ex(im)plicitly • Let user decide whether to take lower QoS or clear call • Implement dynamic QoS control, not static allocation • Support QoS class mapping among diverse networks • Allow QoS choices for call control, availability (future) • Communicate the Y.1541 QoS classes directly
Achieving QoS in IP Networks -- Step 3: Realize QoS Classes via Network Mechanisms A sampling of available QoS control strategies … • Admission control / resource reservation (IETF: RSVP, RSVP-TE, MPLS CR-LDP, ... ) • Priority queuing (IETF: DIFFSERV AF, EF PHBs) • Traffic segregation / routing control (IETF: MPLS-based VPNs) • Protection switching (SG 13: Rec. Y.1720) • Mechanisms should be activated/controlled by signaling Y.1541 QoS classes among networks
IP Network QoS Control:Open Issues and Discussion Topics • IP QoS signaling: requirements, principles, functions • Will networks signal “consumption” of impairment budgets? • Can networks signal commitments to “better” QoS values? • IP network “call” control, availability specifications • QoS interworking among networks ( IP, FR, ATM ...) • IP QoS mechanisms: standardized or proprietary? • Broadcast quality digital video on IP-based networks • Coordinated effort involving several ITU-T SGs, ITU-R, IETF, other stake holders is warranted