Transcript Slide 1
Overview of VoIP Interoperability Interprovider QoS Aspects from FCC NRIC VI FG3 Final Report, December 2003 http://www.nric.org/fg/charter_vi/fg3/NRIC6FG3FinalReport.pdf Presented by Dave McDysan [email protected] 7/16/2015 1 Public Telecommunication Services PSTN Carrier A Internet Carrier B ISP A Network Interconnection ISP B Carrier C ISP C Access Networks Wireless/ Satellite Circuit Wireline Circuit DSL Wireline Packet Cable Wireless/ Satellite Packet Users Voice 7/16/2015 Data Voice Voice Data VoIP Data VoIP Data VoIP Data VoIP Broadband 2 Access Quality of Service (as defined by NRIC VI FG3 Section 3.4.1) • Metrics – Quantitative measures of quality • Voice Quality • Quantities: IP transfer delay, loss ratio, delay variation – ITU-T Y.1540, IETF IPPM • Reference configurations & numerical objectives – ITU-T Y.1541 • Mapping of packet performance to speech quality • Mechanisms – Specific methods to achieve QoS (metrics) • Signaling based admission control • Intra-provider QoS – IETF RSVP signaling, DOCSIS, etc. • Inter-provider QoS – Provision sufficient capacity to meet metrics – IETF Diffserv packet (re)marking, policing, PHBs, and PDBs 7/16/2015 3 Table I.1/G.1010 – Performance targets for audio and video applications Application Mediu m 7/16/2015 Degree of symmetry Typical data rates Key performance parameters and target values One-way delay Delay variation Informatio n loss (Note 2) Audio Conversation al voice Two-way 4-64 kbit/s <150 ms preferred (Note 1) <400 ms limit (Note 1) < 1 ms < 3% packet loss ratio (PLR) Audio Voice messaging Primarily one-way 4-32 kbit/s < 1 s for playback < 2 s for record < 1 ms < 3% PLR Audio High quality streaming audio Primarily one-way 16-128 kbit/s (Note 3) < 10 s << 1 ms < 1% PLR Video Videophone Two-way 16-384 kbit/s < 150 ms preferred (Note 4) <400 ms limit < 1% PLR Video One-way One-way 16-384 kbit/s < 10 s < 1% PLR Other Lipsynch: < 80 ms NOTE 1 – Assumes adequate echo control. NOTE 2 – Exact values depend on specific codec, but assumes use of a packet loss concealment algorithm to minimise effect of packet loss. NOTE 3 – Quality is very dependent on codec type and bit-rate. NOTE 4 – These values are to be considered as long-term target values which may not be met by current technology. 4 End-to-end Metrics Table 1/Y.1541 – Provisional IP network QoS class definitions and network performance objectives Network performance parameter QoS Classes Nature of network performance objective Class 0 Class 1 Class 2 Class 3 Class 4 Class 5 Unspecified IPTD Upper bound on the mean IPTD (Note 1) 100 ms 400 ms 100 ms 400 ms 1s U IPDV Upper bound on the 1 10–3 quantile of IPTD minus the minimum IPTD (Note 2) 50 ms (Note 3) 50 ms (Note 3) U U U U IPLR Upper bound on the packet loss probability 1 × 10–3 (Note 4) 1 × 10–3 (Note 4) 1 × 10–3 1 × 10–3 1 × 10–3 U IPER Upper bound 1 × 10–4 (Note 5) U Table VI.1/Y.1541 – Possible association of Y.1541 QoS classes with differentiated services IP transfer service IP QoS class Remarks Best Effort PDB Unspecified QoS class 5 A legacy IP service, when operated on a lightly loaded network may achieve a good level of IP QoS PDBs based on Assured Forwarding QoS classes 2, 3, 4 The IPLR objective only applies to the IP packets in the higher priority levels of each AF class. The IPTD applies to all packets PDBs based on Expedited Forwarding QoS classes 0 and 1 http://www.itu.int/rec/recommendation.asp?type=products&lang=e&parent=T-REC-Y 7/16/2015 5 Hypothetical Reference Path IP network cloud UNI UNI TE AG IG IG AG TE LAN LAN Non-IP net Customer installation Network section Network section Non-IP net End-to-end network (Bearer QoS) Customer installation User-to-user connection (Teleservice QoS) TE Terminal Equipment AG Access GW IG Internetwork GW UNI User Network Interface Y.1541 F05 Figure III.3/Y.1541 – Hypothetical reference path for QoS class 0 7/16/2015 6 Summary of Standards Gaps • Metrics – Use standard measurement (e.g., RTCP XR RFC 3611) and data interchange formats – 3GPP QoS standards not compatible with Y.1541 • Mechanisms – Best practices for DDoS attacks identification & mitigation – Best practice for DSCP remarking – Standardize Diffserv PHD and PDB at interdomain boundaries – Industry experience on meeting QoS metrics 7/16/2015 7