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Day 1-t4 roland-schott-20120523


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LTE World Summit Barcelona May 2012
Day 1

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Day 1-t4 roland-schott-20120523

  1. 1. QoS Strategies for IMS & VoLTERoland Schott – Project Manager & Architect, Fixed Mobile Engineering Germany public Roland Schott 23.05.2012 1
  2. 2. Overview. Introduction QoS Basic Functions Fixed Network Approach Mobile Backhauling IMS All IP / VoLTE QoS Functions for EPS Audio Codices Conclusions public Roland Schott 23.05.2012 2
  3. 3. Overview of current Deutsche Telekom Group Networks. Mobile Networks Fixed Networks  Service offering in Europe in 15 countries with 0,6 –  Service offering in Europe in 11 countries with 0,6 – 82 Mio. inhabitants. 82 Mio. inhabitants. Case Study Germany: Case Study Germany:  QoS functions in mobile networks available.  QoS functions in fixed networks available. public Roland Schott 23.05.2012 3
  4. 4. A VoLTE Solution requires Ubiquity, Flexibility & Quality.  Independence of services from access network 1 Ubiquity  Integration of legacy networks (e.g. GSM, PSTN)  Seamless 2G/3G/4G/WiFi mobility  Full int. roaming support in mobile networks  Enables service evolution  Fixed-mobile convergence 2 Flexibility  “Docking station” for new applications  Various charging options  Scalability  Telco-grade Quality-of-Service  Security 3 Quality  Reliability  Fulfilment of regulatory requirements  Replacement of legacy CS hardware public Roland Schott 23.05.2012 4
  5. 5. Drivers for IP Data Volume are Broadband-Internet, mobile Internetand Migration to All IP.QoS Mechanisms can handle increasing Data Traffic appropriate and enable Service Differentiation. Mobile Data Volume Germany Data Traffic requires appropriate treatment Textbox Headline  Mobile data volume in Germany has increased exponentially.  Broadband data volume has increased linearly.  Always-On services and mobile users are migrating to IP today.  Machine to Machine Communication Traffic Volume Broadband Germany Textbox Headline (automotive, metering) will become an additional driver for IP communication.  M2M (automotive, metering), IMS (Voice services) and IPTV services require appropriate QoS and QoE.  QoS mechanisms are a possibility to operate increasing network bandwidth. Ref.: Bundesnetzagentur Jahresbericht 2010 public Roland Schott 23.05.2012 5
  6. 6. QoS Mechanisms on different Levels ensuring QoS in fixedNetworks. Traffic Differentiation on Transport Level Implemented with DiffServ  QoS means Hop-by-Hop and ensures alone no E2E 100Mb/s 100Mb/s LAN Quality. 100Mb/s LAN 10Mb/s  DiffServ QoS traffic classes are always traffic 10Mb/s User A User B aggregates. No QoS Guaranty for Single-Users.  Required Criteria: Best Effort Traffic without guaranty 10Mb/s LAN should be available and droppable. 100Mb/s  (E2E QoS Mechanisms like IntServ do not scale in Carrier-Networks). Call Admission Control on Control Level RACS / Call Admission MechanismsSubscriber A PSTN  For fixed Networks call admission control mechanisms IMS are available. 1  RACS (busy tone) implements same look & feel like in IP- PSTN/mobile networks for ensuring voice quality. Platform 2 T-Home  Additionally rate adaptive codices help for ensuring voice quality. 3 RACS = Ressource Admission Control public Roland Schott 23.05.2012 6
  7. 7. DiffServ is a scalable differentiation mechanism in the IP World. Differentiated Service Mechanism & Class of Service Service Classes Particular Quality Parameter Example: Possible SLA Values Delay Jitter Loss Voice Delay Jitter 30 ms 20 ms 2% Gold 60 ms 40 ms 3% Packet Access Loss Bandwidth Silver 100 ms 40 ms 0.5% Best Effort --- --- --- Classification Recognition of communication packets authorized for Voice different service qualities (Re)-Marking Setting the code point for the traffic class determined by the classification process Gold Queuing/ Queue scheduling determines how each queue is served Scheduling to fulfill priority & bandwidth guarantees. Silver Shaping Limits the traffic rate on the outgoing interface. Best Effort Policing The (drop) policy determines how to drop packets from the queues when the interface gets congested. public Roland Schott 23.05.2012 7
  8. 8. QoS Functions can be used for Mobile Backhauling. Mobile Backhaul Traffic requires QoS Concept with Service Differentiation 10 Gb 1Gb eNodeB RiFu 1Gb 10 Gb MPLS AGS NT eNodeB NT 10 Gb 1Gb eNodeB eNodeB  Fixed and mobile traffic are transported over the same MPLS aggregation network.  Aggregation Network supports QoS functionality.  With LTE increasing mobile backhaul traffic is expected.  Differentiating QoS Concept tackles bandwidth situation. public Roland Schott 23.05.2012 8
  9. 9. VoLTE & QoS: LTEe requires a QoS based Voice Solution. VoLTE & EPC architectural Overview Characteristics  LTE offers bandwidth for data services of about 100 Mbps downstream. SIP AS MMTEL AS SMSC SCP HLR Legacy CS HSS Sh Mobile Core  LTE offer pure IP based data access & requires a voice solution. MAP CAP SIP/ISC Cx SIP/ISC  The preferred voice solution is a MSC-S converged one. VoLTE is the IMS based SIP/ISC Mg/Mj voice solution for LTE. Rx PCRF SGs  VoLTE promises lower call setup times MME CSCF Gx compared to CSFB. MGW IP/ATM/TDM other S11 S1-MME Backbone networks  LTE offers inherent QoS mechanisms S1-U RTP/UDP/IP A, Iu which can be combined with PCC/PCRF LTE Access S/P- GW SGi functionality for the EPC. external UTRAN/ IP networks GERAN  QoS based business models seem EUTRAN feasible in minimum required to EPS Solution distinguish voice from data service.Possible Architecture - Symbolic Picture public Roland Schott 23.05.2012 9
  10. 10. VoLTE has various Levels of Bearer. E-UTRAN EPC Internet UE eNB S-GW P-GW Peer Entity End-to-End Service EPS Bearer External Bearer E-RAB S5/S8 Bearer Radio Bearer S1 Bearer Radio S1 S5/8 SGi public Roland Schott 23.05.2012 10
  11. 11. Network initiated QoS Control for IP Flows. QoS enabling via Policy and Charging Control (PCC) Characteristics  Network-initiated QoS: Core Network 1. Application Signalling e.g. IMS SIP  dedicated bearer procedure AF Application to the terminal e.g. uplink (P-CSCF) packet filtering 2. Session Information e.g. type of service, bit rate  dedicated bearer procedure Rx to the RAN e.g. QoS Info 3. Subscription Info PCRF SPR  access agnostic 4. Policy Sp Decision AF = Application Function 5. PCC Rule Gx OFCS PCRF = Policy and Charging Gz Rules Function 5. Credit PCEF Gy management OCS SPR = Subscription Profile Access BBE Repository 7. Activate & modify bearer PDN Interface SGi PCEF = Policy and Charging Access Network PDN GW Enforcement Function 7. Bearer 8. Uplink IP flow 8. Service data Binding bearer mapping flow detection BBE = Bearer Binding Function public Roland Schott 23.05.2012 11
  12. 12. Dynamic PCC Rule. Type of Element PCC Rule Element CommentRule Definition Rule Identifier Referencing PCC rule between PCRF and PCEFService Data Flow detection in PCEF Service Data Flow (SDF) Template List of packet filters for detection of service data flow Precedence Determines order in which service data flows are applied in PCEFPolicy Control i.e. gating and QoS Gate Status Indicates gate open/closedcontrol QoS Class Identifier (QCI) Packet Forwarding Behaviour UL and DL max. bit rates Max. UL/DL bitrates auth. for SDF UL and DL Guaranteed Bit Rates Guaranteed UL/DL bitrates authorised (GBR) for SDF Allocation & Retention Priority (ARP) ARP for the SDF (Pre-emption & CAC)Charging Control Charging Key Charging Key to be applied for SDF Charging Method Required Charging Method for PCC Rule Measurement Method Indicates whether SDF data volume, duration etc. shall be measured public Roland Schott 23.05.2012 12
  13. 13. Standardised QCI Parameters. Packet Delay Packet Error QCI Resource Type Priority Services Budget Loss Rate 1 GBR 2 100 ms 10-2 Conversational Voice Conversational Video (live 2 4 150 ms 10-3 stream) 3 3 50 ms 10-3 Real-Time Gaming Non-Conversational Video 4 5 300 ms 10-6 (buffered stream) 5 Non - GBR 1 100 ms 10-6 IMS signalling Video (buffered stream) 6 6 300 ms 10-6 TCP e.g. progressive video, email, www etc. Voice, Video (live 7 7 100 ms 10-3 streaming) interactive gaming Video (buffered stream) 8 8 300 ms 10-6 TCP e.g. progressive video, email, www etc. Video (buffered stream) 9 9 300 ms 10-6 TCP e.g. progressive video, email, www etc. Ref.: 3 GPP public Roland Schott 23.05.2012 13
  14. 14. Service Data Flow Detection & Mapping to downlink Traffic. Service Data Flow Detection Characteristics Downlink IP packets from the PDN  Association between PCC for this UE and IP address Rule and bearer is referred to as bearer binding.  Bearer binding is done in Bearer Binding Function (BBF) Bearer located in PCEF. No match  BBF triggers resource reservation in access network Precedence match Service and ensures providing of QoS Bearer Data Flow for authorised QoS of PCC Rule. templates match No match (downlink)  A single EPS bearer may be used to carry traffic described by multiple PCC Rules. Bearer match  BBF maps QCI of PCC Rule (IP Flow related and access agnostic) to EPS bearer QCI of no match & discard GTP. public Roland Schott 23.05.2012 14
  15. 15. EPS Bearers for PDN Connections. EPS Bearers are transport over GTP Tunnels across S1 and S5/8 Terminal UE PDN connection #1 EPS Bearer #1 TFT Filter #1 APN, Bearer ID, IP address etc. Precedence QoS parameters etc. Application 2 Filter #n EPS Bearer #n TFT Application 1 PDN connection #n Bearer ID, Precedence APN, QoS parameters etc. IP address etc. Serving PDN GW eNodeB MME IP Flows UL TFT GW DL TFT GTP Tunnel PDN UL TFT DL TFT GTP Tunnel Ref.: 3 GPP TFT = Traffic Flow Template public Roland Schott 23.05.2012 15 GTP = GPRS Tunnelling Protocol
  16. 16. Delay in Packet-Networks influences the Voice Quality.Delay causes echo, MOS do not have to be decreased by Delay necessarily. Reference: ITU-T public Roland Schott 23.05.2012 16
  17. 17. Comparison of Audio Codices.Audio Codec can increase Voice Quality. G.711 G.722 AMR WB/ ILBC Skype (Silk) G722.2 Technology log PCM Sub-band ACELP FB-LPC proprietary ADPCM (IETF) 8000, 12000, * 8000 Hz = Narrow Band Audio BW [Hz] 300-3400 50-7000 50-7000 300-3400 16000, 12000 Hz = Medium Band 16000 Hz = Wide Band 24000* 24000 Hz = Superwide Band 6.6, 8.85, 12.65, 13.33 (30 ms frames), Bit rates [kbit/s] 48, 56, 64 48, 56, 64 14.25, 15.85, 18.25, 15.2 (20 ms frames) 6 - 40 19.85, 23.05, 23.85 Frame Length 0.125 20, 40, 60, 0,125 20 20, 30 [ms] (2 samples) 80, 100 MOS bis 4.5 bis 4.5 4,0 - 4.5 4.14 4,49 public Roland Schott 23.05.2012 17
  18. 18. Overview Voice Codices. Royalty-free super wideband codices in IETF discussion (OPUS): SILK  Skype‘s loss-resilient, adaptive-rate codec with sampling rates between 8 kHz and > 24 kHz CELT  Xiph‘s low-delay, adaptive rate codec, with sampling rates between 32 kHz and 96 kHz, stereo (at 160 kbit/s) Frequency Band Audio hybrid Codec CELT Enhanced Speech from Codec from Skype Bit Rate Reference: IETF public Roland Schott 23.05.2012 18
  19. 19. Conclusions.  QoS based function are available for VoLTE & IMS.  DiffServ is the appropriate QoS approach for IP transport.  PCRF is required to handle QoS quality on the mobile access link.  Introduction of innovative audio codices in the IP world offers new opportunities regarding voice quality.  Convergent QoS solution offers synergy effects. public Roland Schott 23.05.2012 19