Transmission resource management

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Transmission resource management

  1. 1. Transmission Resource Management SRAN5.0 Feature Parameter Description Issue 03 Date 2011-09-30 HUAWEI TECHNOLOGIES CO., LTD.
  2. 2. Copyright © Huawei Technologies Co., Ltd. 2011. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means without prior written consent of Huawei Technologies Co., Ltd. Trademarks and Permissions and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd. All other trademarks and trade names mentioned in this document are the property of their respective holders. Notice The purchased products, services and features are stipulated by the contract made between Huawei and the customer. All or part of the products, services and features described in this document may not be within the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements, information, and recommendations in this document are provided "AS IS" without warranties, guarantees or representations of any kind, either express or implied. The information in this document is subject to change without notice. Every effort has been made in the preparation of this document to ensure accuracy of the contents, but all statements, information, and recommendations in this document do not constitute the warranty of any kind, express or implied. Huawei Technologies Co., Ltd. Address: Huawei Industrial Base Bantian, Longgang Shenzhen 518129 People's Republic of China Website: http://www.huawei.com Email: support@huawei.com
  3. 3. SingleRAN Transmission Resource Management Contents Contents 1 Introduction ................................................................................................................................1-1 1.1 Scope ............................................................................................................................................ 1-1 1.2 Intended Audience ........................................................................................................................ 1-1 1.3 Change History.............................................................................................................................. 1-1 2 Overview of TRM .......................................................................................................................2-1 2.1 Definition of TRM........................................................................................................................... 2-1 2.2 Structure of TRM Functions .......................................................................................................... 2-1 2.3 Similarities and Differences Between 2G, 3G, and Co-Transmission Systems ............................ 2-3 2.3.1 Transmission Resources ...................................................................................................... 2-3 2.3.2 Load Control ......................................................................................................................... 2-3 2.3.3 User Plane Processing and QoS.......................................................................................... 2-4 2.3.4 Differences of Co-TRM From 2G TRM and 3G TRM ........................................................... 2-5 2.4 Benefits of TRM ............................................................................................................................. 2-5 3 Transmission Resources ........................................................................................................3-1 3.1 Overview of Transmission Resources ........................................................................................... 3-1 3.2 Physical Transmission Resources ................................................................................................ 3-3 3.2.1 Physical Layer Resources for ATM Transmission ................................................................ 3-4 3.2.2 Physical Layer Resources for TDM Transmission................................................................ 3-4 3.2.3 Physical and Data Link Layer Resources for HDLC Transmission ...................................... 3-4 3.2.4 Physical and Data Link Layer Resources for IP Transmission............................................. 3-4 3.3 Logical Ports and Resource Groups ............................................................................................. 3-5 3.3.1 Introduction to LPs................................................................................................................ 3-5 3.3.2 ATM LPs at the RNC ............................................................................................................ 3-7 3.3.3 IP LPs at the BSC/RNC/MBSC ............................................................................................ 3-8 3.3.4 LPs at the NodeB ................................................................................................................. 3-9 3.3.5 LPs at the BTS ................................................................................................................... 3-10 3.3.6 Resource Groups at the BSC/RNC .................................................................................... 3-10 3.4 Path Resources ........................................................................................................................... 3-10 3.4.1 AAL2 Paths ......................................................................................................................... 3-10 3.4.2 IP Paths .............................................................................................................................. 3-10 3.5 Networking Application ................................................................................................................ 3-12 3.5.1 2G and 3G Networking ....................................................................................................... 3-12 3.5.2 Co-Transmission Networking ............................................................................................. 3-13 4 Quality of Service .....................................................................................................................4-1 4.1 Overview ....................................................................................................................................... 4-1 4.2 Transport Priorities ........................................................................................................................ 4-1 4.2.1 DSCP .................................................................................................................................... 4-1 4.2.2 VLAN Priorities ..................................................................................................................... 4-2 Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd i
  4. 4. SingleRAN Transmission Resource Management Contents 4.2.3 Priority Queues ..................................................................................................................... 4-4 4.2.4 Priority Queues and Rate Limiting in the NodeB .................................................................. 4-5 4.3 Service QoS .................................................................................................................................. 4-6 4.4 Transmission Resource Mapping .................................................................................................. 4-6 4.4.1 Traffic Bearers ...................................................................................................................... 4-6 4.4.2 Transport Bearers ................................................................................................................. 4-7 4.4.3 Mapping from Traffic Bearers to Transport Bearers ............................................................. 4-7 4.5 Summary ..................................................................................................................................... 4-12 5 Load Control ..............................................................................................................................5-1 5.1 Overview of Load Control .............................................................................................................. 5-1 5.2 Definition and Calculation of Transmission Load .......................................................................... 5-2 5.3 Calculation of Reserved Bandwidth .............................................................................................. 5-2 5.3.1 Calculation of Bandwidth Reserved for 2G Signaling .......................................................... 5-2 5.3.2 Calculation of Bandwidth Reserved for Traffic ..................................................................... 5-3 5.4 Load Thresholds............................................................................................................................ 5-4 5.5 Admission Control ......................................................................................................................... 5-4 5.5.1 Admission Process ............................................................................................................... 5-5 5.5.2 Admission Strategy ............................................................................................................... 5-5 5.5.3 Load Sharing ........................................................................................................................ 5-8 5.5.4 Load Balancing ..................................................................................................................... 5-9 5.5.5 Preemption ......................................................................................................................... 5-11 5.5.6 Queuing .............................................................................................................................. 5-12 5.6 Load Reshuffling and Overload Control ...................................................................................... 5-12 5.6.1 Congestion Detection ......................................................................................................... 5-12 5.6.2 Overload Detection ............................................................................................................. 5-13 5.6.3 Congestion and Overload Handling ................................................................................... 5-14 5.7 Summary ..................................................................................................................................... 5-15 6 User Plane Processing ............................................................................................................6-1 6.1 Overview of User Plane Processing.............................................................................................. 6-1 6.2 Scheduling and Shaping ............................................................................................................... 6-2 6.2.1 RNC/BSC Scheduling and Shaping ..................................................................................... 6-2 6.2.2 NodeB Scheduling and Shaping .......................................................................................... 6-3 6.2.3 BTS Shaping ........................................................................................................................ 6-3 6.3 Iub Overbooking ............................................................................................................................ 6-3 6.4 Congestion Control of Iub User Plane .......................................................................................... 6-4 6.5 Downlink Iub Congestion Control Algorithm .................................................................................. 6-5 6.5.1 Overview of the Downlink Iub Congestion Control Algorithm ............................................... 6-5 6.5.2 RNC RLC Retransmission Rate-Based Downlink Congestion Control Algorithm ................ 6-6 6.5.3 RNC Backpressure-Based Downlink Congestion Control Algorithm ................................... 6-8 6.5.4 NodeB HSDPA Adaptive Flow Control Algorithm ................................................................. 6-9 6.6 Uplink Iub Congestion Control Algorithm .................................................................................... 6-12 Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd ii
  5. 5. SingleRAN Transmission Resource Management Contents 6.6.1 Overview of the Uplink Iub Congestion Control Algorithm ................................................. 6-12 6.6.2 NodeB Backpressure-Based Uplink Congestion Control Algorithm (R99 and HSUPA)..... 6-13 6.6.3 NodeB Uplink Bandwidth Adaptive Adjustment Algorithm .................................................. 6-14 6.6.4 RNC R99 Single Service Uplink Congestion Control Algorithm ......................................... 6-15 6.6.5 NodeB Uplink Congestion Control Algorithm for Cross-Iur Single HSUPA Service ........... 6-15 6.7 Dynamic Bandwidth Adjustment Based on IP PM ...................................................................... 6-16 7 Engineering Guidelines...........................................................................................................7-1 7.1 Configuring Co-TRM (with GSM BSC and UMTS RNC Combined) ............................................. 7-1 7.2 Using Default TRMLOADTH Table ................................................................................................ 7-1 8 Parameters .................................................................................................................................8-1 9 Counters ......................................................................................................................................9-1 10 Glossary ..................................................................................................................................10-1 11 Reference Documents .........................................................................................................11-1 Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd iii
  6. 6. SingleRAN Transmission Resource Management 1 Introduction 1 Introduction 1.1 Scope This document mainly describes the management of transmission resources at the base station controller. The transmission resources refer to those carried on the Abis interface of the 2G system and on the Iub interface of the 3G system, and those shared by the Abis and Iub interfaces of the common transmission (co-transmission) system. This document merges the Transmission Resource Management (TRM) feature descriptions of the 2G, 3G, and co-transmission systems. It describes transmission resources, Quality of Service (QoS), load control, user plane processing, and associated parameters. It is applicable for R99, HSDPA, and HSUPA. In this document, HSDPA transport resource management (WRFD-01061014 HSDPA Transport Resource Management) and HSUPA transport resource management (WRFD-01061207 HSUPA Transport Resource Management) mainly refer to the transmission resource mapping and load control.  The base station controllers of the 2G, 3G, and co-transmission systems are BSC, RNC, and Multi-Mode Base Station Controller (MBSC) respectively.  MBSC is the GSM+UMTS multi-mode base station controller introduced in Huawei SRAN3.0 solution.  SRAN3.0 supports the co-transmission resource management (Co-TRM) feature (corresponding to MRFD-211503 Co-Transmission Resources Management on MBSC) only in the co-transmission scenario where the MBSC is deployed on the base station controller side, and the MBTS is deployed on the base station side. In this scenario, Co-TRM refers to the common management of IP logical ports (LPs) transmission resources when the 2G system and the 3G system implement IP-based co-transmission on the Abis and Iub interfaces. Co-TRM improves the usage of transmission resources and provides the QoS services. In the Co-TRM feature, Abis and Iub share IP LPs, and IP LPs share IP physical transmission resources. The 2G IP paths are independent of the 3G IP paths. Co-TRM implements the common load control and traffic shaping within the shared LPs.  SRAN5.0 also supports the Co-TRM feature in the scenario where the GSM BSC and the UMTS RNC are deployed separately, and IP-based co-transmission is implemented on the base station side. In this scenario, Abis and Iub do not share LPs and physical ports. Co-TRM improves the transmission bandwidth utilization in the GSM and UMTS co-transmission scenario. For details, see Bandwidth Sharing of MBTS Multi-Mode Co-Transmission Feature Parameter Description. 1.2 Intended Audience This document is intended for:  Personnel who are familiar with WCDMA or GSM basics  Personnel who need to understand the TRM feature of the 2G, 3G, and co-transmission systems  Personnel who work with Huawei products 1.3 Change History This section provides information on the changes in different document versions. There are two types of changes, which are defined as follows:  Feature change: refers to the change in the Transmission Resource Management feature.  Editorial change: refers to the change in wording or the addition of the information that was not described in the earlier version. Document Issues The document issues are as follows:  03 (2011-09-30) Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 1-1
  7. 7. SingleRAN Transmission Resource Management  02 (2011-03-30)  01 (2010-05-15)  1 Introduction Draft (2010-03-30) 03 (2011-09-30) This is the document for the third commercial release of SRAN5.0. Compared with 02 (2011-03-30) of SRAN5.0, this issue incorporates the following changes: Change Type Change Description Parameter Change Feature change None None. Editorial change The algorithm for NodeB backpressure-based uplink None. congestion control is optimized. For details, see the section "NodeB Backpressure-Based Uplink Congestion Control Algorithm (R99 and HSUPA)." 02 (2011-03-30) This is the document for the second commercial release of SRAN5.0. Compared with 01 (2010-05-15) of SRAN5.0, this issue incorporates the following changes: Change Type Change Description Parameter Change Feature change None None. Editorial change Optimized the description of principles of load balancing. For details, See "Principles of Load Balancing". None. 01 (2010-05-15) This is the document for the first commercial release of SRAN5.0. Compared with Draft (2010-03-30) of SRAN5.0, this issue optimizes the description. Draft (2010-03-30) This is the draft of the document for SRAN5.0. Compared with 03 (2010-01-20) of SRAN3.0, this issue incorporates the following changes: Change Type Change Description Parameter Change Feature change The description of LPs at the BTS is added. None. The description of Co-TRM in the MBTS None. co-transmission scenario where the GSM BSC and the UMTS RNC are deployed separately is added. Editorial change None. Issue 03 (2011-09-30) None. Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 1-2
  8. 8. SingleRAN Transmission Resource Management 2 Overview of TRM 2 Overview of TRM 2.1 Definition of TRM TRM is the management of transmission resources on the interfaces in various networking modes. The transmission interfaces of the 2G system include Abis, Ater, and A; the transmission interfaces of the 3G system include Iub, Iur, Iu-CS, and Iu-PS. Compared with the transmission on the other interfaces, the transmission on the Abis and Iub interfaces has higher costs, more complicated networking modes, and greater impact on system performance. Therefore, this document mainly describes the TRM for the Iub and Abis interface. In the co-transmission system, TRM implements common management of transmission resources shared by the Abis and Iub interfaces and so TRM is also focused on the Abis and Iub interfaces. TRM in the co-transmission system is called Co-TRM. Transmission resources are one type of resource that the radio network access provides. Closely related to TRM algorithms are Radio Resource Management (RRM) algorithms, such as the scheduling algorithm and load control algorithm for the Uu interface. The TRM algorithm policies should be consistent with the RRM algorithm policies. 2.2 Structure of TRM Functions Figure 2-1 shows the structure of TRM functions. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 2-1
  9. 9. SingleRAN Transmission Resource Management 2 Overview of TRM Figure 2-1 Structure of the TRM functions As shown in Figure 2-1, the TRM feature covers the following aspects:  Transmission resources involved in TRM include physical and logical resources. For details, see section 3 "Transmission Resources."  Load control is applied to the control plane in TRM. It includes admission control, load reshuffling (LDR), and overload control (OLC). For details, see section 5 "Load Control."  QoS priority mapping, shaping, and scheduling, dynamic bandwidth adjustment based on IP Performance Monitor (PM), and congestion control are applied to the user plane in TRM. For details, see section 4 "Quality of Service" and 6 "User Plane Processing." Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 2-2
  10. 10. SingleRAN Transmission Resource Management 2 Overview of TRM 2.3 Similarities and Differences Between 2G, 3G, and Co-Transmission Systems 2.3.1 Transmission Resources Overview  In the SingleRAN 3.0 solution, the related concepts and configurations of the 2G and 3G systems in IP transmission mode are almost the same. − The 2G and 3G systems can use the same physical transmission resources, data link layer protocols, and IP-based interface boards. For details, see section 3.2.4 "Physical and Data Link Layer Resources for IP Transmission." − The concepts and functions of LPs, resource groups, and paths for the 2G and 3G systems are the same. For details, see section 3.3 "Logical Ports and Resource Groups." − The 2G and 3G systems can use the same commands to configure LPs, resource groups, and IP paths. For details, see section 3.3.3 "IP LPs at the BSC/RNC/MBSC", 3.3.6 "Resource Groups at the BSC/RNC", and 3.4.2 "IP Paths."  The Abis interface of the 2G system and the Iub interface of the 3G system are applied to almost the same networking scenarios, which include direct connection, bandwidth variation, and convergence. For details, see section 3.5.1 "2G and 3G Networking." Characteristics of 2G TRM The 2G system supports the TDM and HDLC transmission modes. For details about available transmission resources, see section 3.2.2 "Physical Layer Resources for TDM " and 3.2.3 "Physical and Data Link Layer Resources for HDLC Transmission." Characteristics of 3G TRM  The 3G system supports the ATM transmission mode. Transmission resources of the 3G system are classified into physical transmission resources, LPs, resource groups, and path resources. For details, see section 3.2.1 "Physical Layer Resources for ATM ", 3.3.2 "ATM LPs at the RNC", 3.3.6 "Resource Groups at the BSC/RNC", and 3.4.1 "AAL2 Paths."  The LPs of the 3G system can also be applied in RAN sharing scenario for transmission resource admission control. For details, see section 3.3.1 "Introduction to LP."  The 3G system also supports configuration of NodeB LPs. For details, see section 3.3.4 "LPs at the NodeB."  For the Iub hybrid IP transmission mode, non-QoS paths can be further classified into high-quality paths and low-quality paths. For details, see section 3.4.2 "IP Paths."  The Iub interface of the 3G system supports the ATM&IP dual stack networking and hybrid IP networking. For details, see section 3.5.1 "2G and 3G Networking." 2.3.2 Load Control Overview  The 2G system and the 3G system perform load control in respective control planes. Their load control methods include admission control, LDR, and OLC. For details, see section 5 "Load Control." − For the ATM, IP, and HDLC transmission modes, the definitions and calculation methods of transmission load of the 2G and 3G systems are the same. For details, see section 5.2 "Definition and Calculation of Transmission Load." Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 2-3
  11. 11. SingleRAN Transmission Resource Management 2 Overview of TRM − Both 2G system and 3G system make requests for admission of services according to the bandwidth reserved for services, and both calculate the bandwidth reserved for services based on activity factors. For different services of the 2G and 3G systems, the reserved bandwidth differs. For details, see section 5.3.2 "Calculation of Bandwidth Reserved for Traffic." − In the process of transmission resources admission control, the 2G and 3G systems have the same admission processes, the same admission strategies, and the same principles of preemption and queuing. Switches and actions of preemption and queuing in the 2G and 3G systems are different. For details, see section 5.5 "Admission Control." − In the processes of LDR and OLC, the principles of congestion and overload detection for the 2G and 3G systems are the same, but the procedures for handling congestion and overload are different. For details, see section 5.6 "Load Reshuffling and Overload Control."  In the SRAN3.0 solution: − The 2G and 3G systems use the same load threshold table template and use the same command to configure the table. For details, see section 5.4 "Load Thresholds," − The 2G and 3G systems use the same activity factor table template and use the same command to configure the table. For details, see section 5.3.2 "Calculation of Bandwidth Reserved for Traffic." Characteristics of 2G TRM The 2G Abis signaling needs to calculate the reserved bandwidth. For details, see section 5.3.1 "Calculation of Bandwidth Reserved for 2G Signaling." Characteristics of 3G TRM  The GBR of BE services of the 3G system are configurable. For details, see section 5.3 "Calculation of Reserved Bandwidth."  In Iub hybrid transmission mode, the admission of primary and secondary paths is supported in the process of transmission resource admission. For details, see section 5.5.4 "Load Balancing." 2.3.3 User Plane Processing and QoS Overview  The 2G and 3G systems implement leaf LP shaping and hub LP scheduling functions in respective user planes. The related concepts and principles are the same. For details, see section 6.2 "Scheduling and Shaping."  The 2G and 3G systems implement the adjacent-node-oriented mapping from services to transmission resources in respective user planes. The related concepts such as DSCP and queue priority are the same. For details, see 4.2 "Transport Priorities." In the SRAN3.0 solution, the 2G and 3G systems use the same TRMMAP table template and use the same command to configure the mapping from services to transmission resources. For details, see section 4.4 "Transmission Resource Mapping." Characteristics of 2G TRM  In HDLC transmission mode, the HDLC also supports shaping and scheduling functions. For details, see section 6.2.1 "RNC/BSC Scheduling and Shaping."  The mapping from 2G Abis signaling services to transmission resources is not oriented to adjacent nodes and therefore needs to be configured separately. For details, see "Mapping from Abis Signaling Traffic to Transmission Resources." Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 2-4
  12. 12. SingleRAN Transmission Resource Management 2 Overview of TRM Characteristics of 3G TRM  The NodeB of the 3G system also supports shaping and scheduling functions. For details, see section 6.2.2 "NodeB Scheduling and Shaping."  The Iub interface of the 3G system implements a series of congestion control algorithms in the user plane. For details, see section 6.3 "Iub Overbooking."  When the mapping from services to transmission resources is configured, the 3G services are differentiated by user priority, traffic priority, and type of radio bearer. The 3G system also supports configuration of primary and secondary paths. For details, see sections 4.3 "Service QoS" and 4.4 "Transmission Resource Mapping." 2.3.4 Differences of Co-TRM From 2G TRM and 3G TRM Characteristics of Co-TRM in SRAN3.0:  The Abis interface of the 2G system and the Iub interface of the 3G system share IP LPs, and IP LPs share physical IP transmission resources.  Within a shared LP, common load control is implemented based on common load thresholds, that is, common admission strategies and common congestion and overload detection.  In the process of handling overload caused by LP admission, the 2G and 3G systems reserve bandwidth proportionally. For details, see section 5.6.3 "Congestion and Overload Handling."  Common traffic shaping is implemented within a shared LP.  Co-TRM is applicable only to one of the co-transmission networking scenarios. For details, see section 3.5.2 "Co-Transmission Networking." In SRAN5.0, the Co-TRM in the scenario where the GSM BSC and the UMTS RNC are deployed separately, and the GSM and UMTS systems do not share the LPs. In Co-TRM, the management of GSM and UMTS transmission resources is similar to 2G TRM and 3G TRM. The only difference is that Co-TRM has special requirements for BSC or RNC configurations to improve transmission bandwidth utilization. Co-TRM inherits the concepts, principles, and functions of 2G TRM and 3G TRM, which include concepts and functions of paths and LPs, definition and calculation of load, calculation of bandwidth reserved for services, principles and methods of load control, transmission resource mapping, and LP shaping and scheduling. In the Co-TRM feature:  2G IP paths and 3G IP paths are mutually independent.  The 2G system and the 3G system implement transmission resource mapping separately.  The 2G system and the 3G system calculate reserved bandwidth separately.  The 2G system and the 3G system set preemption and queuing switches separately, and take preemption and queuing actions separately.  The 2G system and the 3G system handle congestion and overload separately. 2.4 Benefits of TRM TRM increases the system capacity with the QoS guaranteed and provides differentiated services.  Real-time (RT) services, such as conversational and streaming services RT services do not allow packet loss and are sensitive to delay. The activity of RT services follows an obvious rule. When multiple services access the network, the total actual traffic volume is relatively stable. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 2-5
  13. 13. SingleRAN Transmission Resource Management 2 Overview of TRM − Through the transmission resource mapping, RT services can be mapped to high-priority paths and thus be transmitted preferentially when congestion occurs. This reduces packet loss and transmission delay. For details, see section 4 "Quality of Service." − RT services are admitted at the Maximum Bit Rate (MBR). With appropriate activity factors configured, the access of more users are allowed under the condition that the QoS is guaranteed. Overload control and preemption can achieve differentiated services. For details, see section 5 "Load Control."  Non-real-time (NRT) services, such as interactive and background services NRT services do not have strict requirements for bandwidth. When transmission resources are insufficient, the data can be buffered to reduce the traffic throughput. The activity of NRT services does not follow an obvious rule. When multiple services access the network, the total actual traffic volume fluctuates significantly. − Through transmission resource mapping, NRT services can be mapped to low-priority paths and thus the QoS of RT services can be guaranteed preferentially. For details, see section 4 "Quality of Service." − The TRM feature provides the Guaranteed Bit Rate (GBR) and a user plane congestion control algorithm, which allow the access of more users under the condition that the QoS is guaranteed. For details, see section 6 "User Plane Processing." − Through the Scheduling Priority Indicator (SPI) weighting, bandwidth allocation for NRT services can be differentiated. For details, see section 6 "User Plane Processing." SPI is used to indicate the scheduling priorities of services, and SPI weighting is used to adjust the queuing priorities of scheduling services or to proportionally allocate bandwidth to services in Iub congestion control. A larger SPI weight indicates a higher queuing priority or a higher bandwidth allocated to the Iub interface.  Signaling, such as Signaling Radio Bearer (SRB), Session Initiation Protocol (SIP), Network Control Protocol (NCP), Communication Control Port (CCP), and Abis interface signaling The traffic volume of signaling is low and its performance is closely related to Key Performance Indexes (KPIs) of the network. Therefore, through transmission resource mapping, signaling can be mapped to high-priority paths and the transmission of signaling takes precedence, thus preventing packet loss and transmission delay. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 2-6
  14. 14. SingleRAN Transmission Resource Management 3 Transmission Resources 3 Transmission Resources 3.1 Overview of Transmission Resources The 2G, 3G, and co-transmission systems can use the transmission resources described in Table 3-1. Table 3-1 Transmission resources used by the 2G, 3G, and co-transmission systems Transmission Resource 2G System 3G System Co-Transmission System TDM √ - - HDLC √ - - IP √ √ √ ATM - √ - ATM transmission resources and IP transmission resources can be further classified into physical resources, logical ports, resource groups, and paths. In TDM and HDLC transmission, the user plane data is carried on the timeslots of physical ports. Figure 3-1, Figure 3-2, Figure 3-3 and Figure 3-4 show examples of different transmission resources. Figure 3-1 ATM transmission resources Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 3-1
  15. 15. SingleRAN Transmission Resource Management 3 Transmission Resources Figure 3-2 IP transmission resources of the 3G system Figure 3-3 IP transmission resources of the 2G system Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 3-2
  16. 16. SingleRAN Transmission Resource Management 3 Transmission Resources Figure 3-4 IP transmission resources of the co-transmission system 3.2 Physical Transmission Resources Table 3-2 describes the physical transmission resources used by the 2G, 3G, and co-transmission systems. Table 3-2 Physical transmission resources used by the 2G, 3G, and co-transmission systems Physical 2G TDM 2G HDLC 2G IP 3G ATM 3G IP Co-Transmissio Transmissio Transmissio Transmissio Transmissio Transmissio Transmissio n System n Resource n n n n n E1/T1 √ electrical port √ √ √ √ √ FE/GE electrical port - √ - √ √ GE optical port - - √ - √ √ Unchannelize d STM-1/OC-3c optical port - - √ √ - Channelized √ STM-1/OC-3 optical port √ √ √ √ √ Flex Abis √ resource pool - - - - - Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 3-3
  17. 17. SingleRAN Transmission Resource Management 3 Transmission Resources 3.2.1 Physical Layer Resources for ATM Transmission The physical ports for ATM transmission are as follows: Physical Port Transmission Mode E1/T1 electrical port  IMA  UNI  Fractional ATM  IMA  UNI  Fractional ATM Channelized STM-1/OC-3 optical port Unchannelized STM-1/OC-3c optical port NCOPT 3.2.2 Physical Layer Resources for TDM Transmission The physical ports for TDM transmission are as follows:  E1/T1 electrical port  Channelized STM-1/OC-3 optical port In TDM transmission on the Abis interface, Abis timeslots can be shared as a Flex Abis pool within the BSC. For details about Flex Abis, see Flex Abis Feature Parameter Description of the GBSS. 3.2.3 Physical and Data Link Layer Resources for HDLC Transmission HDLC resources include physical layer resources and data link layer resources, which are listed as follows:  Physical layer resources include E1/T1 electrical port and channelized STM-1/OC-3 optical port.  Data link layer resources refer to HDLC channels. 3.2.4 Physical and Data Link Layer Resources for IP Transmission Table 3-3 describes the physical ports and data link layer protocols for IP transmission. Table 3-3 Physical ports for IP transmission Physical Port Data Link Layer Protocol 2G System 3G System Co-Transmission System E1/T1 electrical port PPP/MLPPP √ √ - FE/GE electrical port Ethernet √ √ √ GE optical port Ethernet √ √ √ Unchannelized STM-1/OC-3c optical port PPP/MLPPP - √ - Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 3-4
  18. 18. SingleRAN Transmission Resource Management 3 Transmission Resources Physical Port Data Link Layer Protocol 2G System 3G System Co-Transmission System Channelized STM-1/OC-3 optical port PPP/MLPPP √ √ √ 3.3 Logical Ports and Resource Groups Logical Ports (LPs) and resource groups are applicable to the 2G, 3G, and co-transmission systems, as described in Table 3-4. Table 3-4 LPs and resource groups applicable to the 2G, 3G, and co-transmission systems LP and 2G TDM 2G HDLC 2G IP 3G ATM 3G IP Co-Transmission Resource Transmission Transmission Transmission Transmission Transmission System Group ATM LP - - - √ - - IP LP - - √ - √ √ Resource group - √ √ √ - 3.3.1 Introduction to LPs LPs are used to configure bandwidth at transmission nodes and perform bandwidth admission and traffic shaping to prevent congestion. After the physical ports and paths are configured, the system can start to operate and services can be established. There are problems, however, in the following scenarios:  Transmission aggregation − Transmission aggregation exists either on the transport network (for example, aggregation of NB1 and NB2, as shown in Figure 3-5) or at the hub NodeB or hub BTS (for example, aggregation of NB3 and NB4 at NB1, as shown in Figure 3-5). − If only physical ports and paths are configured, the bandwidth constraints at the aggregation nodes are unavailable. As shown in Figure 3-5, the total available bandwidth BW0 of NB1 through NB4 is known, but the values of BW1 through BW4 are unknown. Thus, the admission algorithm does not work properly. For example, if the total reserved bandwidth at NB2 exceeds BW2, in the downlink the total volume of data sent to NB2 may exceed BW2, and congestion and packet loss may occur. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 3-5
  19. 19. SingleRAN Transmission Resource Management 3 Transmission Resources Figure 3-5 Transmission aggregation on the Iub or Abis interface NB: NodeB or BTS  BW: bandwidth BW0: bandwidth of physical ports on the RNC or BSC or MBSC RAN sharing in the RNC − In this scenario, operators share the bandwidth at one NodeB and the bandwidth needs to be configured for each operator so that the bandwidth used by each operator does not exceed their respective reserved bandwidth. − If only physical ports and paths are configured, the preceding requirement cannot be fulfilled. To solve the preceding problems, the LP concept is introduced to the TRM feature.  An LP indicates the bandwidth constraints between paths or between other LPs.  An LP can be comprised of only paths. Such an LP is called a leaf LP. A physical port can be a leaf LP.  An LP can also be comprised of only other LPs. Such an LP is called a hub LP. A physical port can be a hub LP.  One key characteristic of LPs is the bandwidth. For an LP, the uplink bandwidth can be different from the downlink bandwidth. LPs can be classified into the following types:  ATM LP: used for bandwidth admission and traffic shaping. Multiple levels of ATM LPs are supported.  IP LP: used for bandwidth admission and traffic shaping. Multiple levels of IP LP are supported. In the 3G TRM, LPs need to be configured on both the RNC and NodeB sides; in the 2G TRM, LPs need to be configured only on the BSC side; in the Co-TRM, LPs need to be configured only on the MBSC side. LPs are configured on the RNC or BSC or MBSC side for the following purposes:  To implement admission control in the aggregation or RAN sharing scenario in the RNC  To implement traffic shaping in the downlink LPs are configured on the NodeB side for the following purposes:  To achieve fairness between local data and forwarded data in the aggregation scenario Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 3-6
  20. 20. SingleRAN Transmission Resource Management  3 Transmission Resources To implement traffic shaping in the RAN sharing scenario For details about LP shaping, see section 6.2 "Scheduling and Shaping." 3.3.2 ATM LPs at the RNC ATM LPs, also called Virtual Ports (VPs), provide the functions of ATM traffic shaping and bandwidth admission. They can be configured on ATM interface boards through the ADD ATMLOGICPORT command. These LPs have the following attributes:  Types of LP: hub LP and leaf LP  Bandwidth: The downlink bandwidth is used for traffic shaping and bandwidth admission, and the uplink bandwidth is used for bandwidth admission only.  Resource management mode: SHARE or EXCLUSIVE, which indicates whether operators in the RAN sharing scenario share the Iub transmission resources. When the ADD AAL2PATH, ADD SAALLNK, or ADD IPOAPVC command is executed to specify the bearer type of an AAL2 path, an SAAL link, or an IPoA PVC as ATMLOGICPORT, the path, link, or PVC can be set to join an LP. The parameters associated with ATM LPs are as follows:  LPNTYPE  TXBW  RXBW  RSCMNGMODE In the ATM transmission aggregation scenario, LPs need to be configured for each NodeB and at each aggregation node; in the RAN sharing scenario, an LP needs to be configured for each operator that shares the NodeB. As shown in Figure 3-6, below is an example of transmission aggregation. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 3-7
  21. 21. SingleRAN Transmission Resource Management 3 Transmission Resources Figure 3-6 Transmission aggregation at LPs NB: NodeB BW: bandwidth BW0: bandwidth of the physical port on the RNC  The leaf LPs, that is, LP1, LP2, LP3, and LP4, have a one-to-one relationship with the NodeBs. The bandwidth of each leaf LP is equal to the Iub bandwidth of each corresponding NodeB.  The hub LP, that is, LP125, corresponds to the hub NodeB. The bandwidth of the hub LP is equal to the Iub bandwidth of the hub NodeB.  The actual rate at a leaf LP is limited by the bandwidth of the leaf LP and the scheduling rate at the hub LP and physical port.  In the transmission resource admission algorithm, the reserved bandwidth of a leaf LP is limited by not only the bandwidth of the leaf LP but also the bandwidth of the hub LP and the bandwidth of the physical port. That is, the total reserved bandwidth of all the LPs under a hub LP cannot exceed the bandwidth of the hub LP. The RNC supports multi-level shaping (a maximum of five levels), which involves leaf LPs and hub LPs. 3.3.3 IP LPs at the BSC/RNC/MBSC IP LPs have the functions of IP traffic shaping and bandwidth admission. They can be configured on IP interface boards through the ADD IPLOGICPORT command. These LPs have the following attributes:  Types of LP: hub LP and leaf LP  Bandwidth: The downlink bandwidth is used for traffic shaping and bandwidth admission, and the uplink bandwidth is used for bandwidth admission only.  Resource management mode: SHARE or EXCLUSIVE, which indicates whether operators in the RAN sharing scenario share the Iub transmission resources. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 3-8
  22. 22. SingleRAN Transmission Resource Management 3 Transmission Resources When the ADD IPPATH command is executed to specify the bearer type of IP path as IPLGCPORT, or when the RNC and MBSC bind the IP LPs through the ADD SCTPLNK command, the path or link can be set to join an LP. IP LPs are similar to ATM LPs in terms of principles and application. The current version supports a maximum of five levels of IP LPs. The parameters associated with IP LPs are as follows:  LPNTYPE  RSCMNGMODE  CIR  OAMFLOWBW 3.3.4 LPs at the NodeB LPs at the NodeB have the function of traffic shaping, which are mainly used to differentiate operators in the RAN sharing scenario. ATM or IP LPs can be configured on the interface board through the ADD RSCGRP command. The LPs have the following attributes:  Types of LPs: ATM and IPv4  Transmit bandwidth: used for traffic shaping  Receive bandwidth: used to calculate the remaining bandwidth for backpressure-based flow control  Port types − For ATM − For LPs, the port types are IMA, UNI, fractional ATM, and unchannelized STM-1. IP LPs, the port types are PPP, MLPPP group, and Ethernet port. In ATM transmission mode, when the ADD AAL2PATH, ADD SAALLNK, or ADD OMCH command is executed to add an AAL2 path, an SAAL link, or an OM channel respectively, the path, link, or channel can be set to join an LP. In IP transmission mode, when the ADD IPPATH command is executed to add an IP path, the path can be set to join an LP so as to add the data traffic volume carried on the path of the local NodeB to the LP. The MML command ADD IP2RSCGRP is executed to bind an LP to the target IP network segment. The command is executed to join the signaling stream, OM traffic, and forwarded data traffic to a specified LP. The parameters associated with LPs at the NodeB are as follows:  BEAR  PT  TXBW  RXBW The LP capabilities of NodeB interface boards are as follows:  Each physical port of the NodeB supports a maximum of four IP LPs.  When a Main Processing & Transmission interface board (WMPT) is configured, each interface board supports a maximum of 4 ATM LPs or a maximum of 8 IP LPs.  When other interface boards are configured, each interface board supports a maximum of 16 ATM LPs or a maximum of 8 IP LPs. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 3-9
  23. 23. SingleRAN Transmission Resource Management 3 Transmission Resources 3.3.5 LPs at the BTS In IP over FE/GE transmission mode, you can run the MML command ADD BTSIPLGCPORT to configure LPs at the BTS. The TXBW parameter is used for traffic shaping in the GSM and UMTS co-transmission to reduce the impact of GSM uplink traffic on the UMTS uplink traffic. The MML command ADD BTSIPTOLGCPORT is used to bind the LPs to the target IP addresses of LPs. The command is executed to join the signaling stream, OM traffic, and data traffic to the LPs. 3.3.6 Resource Groups at the BSC/RNC Resource groups support bandwidth admission but do not support traffic shaping. Resource groups are applicable to ATM and IP transmission modes. Multiple levels of transmission resource groups are supported. To add a resource group, run the ADD RSCGRP command. To join an IP path to a resource group, run the ADD IPPATH command. To associate with ATM paths, run the ADD AAL2PATH command. On the RNC or BSC side, LPs cannot contain transmission resource groups, and transmission resource groups cannot contain LPs either. 3.4 Path Resources Path resources comprise paths in the control plane, user plane, and management plane. The paths in the user plane, that is, AAL2 paths for ATM transmission and IP paths for IP transmission, are key resources. The allocation and management of transmission resources are based on paths. Table 3-5 describes the path resources that can be used by the 2G, 3G, and co-transmission systems. Table 3-5 Path resources that can be used by the 2G, 3G, and co-transmission systems Path 2G TDM 2G HDLC 2G IP 3G ATM 3G IP Co-Transmission Resource Transmission Transmission Transmission Transmission Transmission System AAL2 path - - - √ - - IP path - √ - √ √ - 3.4.1 AAL2 Paths In ATM transmission mode, the following types of AAL2 path can be configured:  CBR  RT-VBR  NRT-VBR  UBR The AAL2 path can be configured through the ADD AAL2PATH command. When an AAL2 path is configured, the TXTRFX and RXTRFX parameters need to be set by running ADD ATMTRF command. These parameters determine the type of the AAL2 path. 3.4.2 IP Paths IP paths can be classified into QoS paths and non-QoS paths. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 3-10
  24. 24. SingleRAN Transmission Resource Management  3 Transmission Resources On QoS paths, different services share the bandwidth of paths. The Per Hop Behavior (PHB) of IP paths is determined by transmission resource mapping. For details about transmission resource mapping, see section 4.4 "Transmission Resource Mapping." PHB is the next-hop behavior of the IP path. Services can be prioritized based on the mapping from PHB to DSCP.  On non-QoS paths, different services do not share the bandwidth of IP paths. The PHB of IP paths is determined by the path type. Non-QoS paths can be further classified into high-quality paths and low-quality paths. The low-quality path, denoted as LQ_xxx, is applicable to only hybrid IP transmission on the Iub interface. In hybrid IP transmission mode, if the physical port is an PPP or MLPPP port, high-quality paths are configured; if the physical port is an Ethernet port, low-quality paths are configured. For details about the hybrid IP transmission on the Iub interface, see section 3.5.1 "2G and 3G Networking." The IP path can be configured through the ADD IPPATH command. For details about the classification of non-QoS paths, see Table 3-6. Table 3-6 Classification of non-QoS paths High-Quality Path Low-Quality Path BE LQ_BE AF11 LQ_AF11 AF12 LQ_AF12 AF13 LQ_AF13 AF21 LQ_AF21 AF22 LQ_AF22 AF23 LQ_AF23 AF31 LQ_AF31 AF32 LQ_AF32 AF33 LQ_AF33 AF41 LQ_AF41 AF42 LQ_AF42 AF43 LQ_AF43 EF LQ_EF Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 3-11
  25. 25. SingleRAN Transmission Resource Management 3 Transmission Resources NOTE  On the Iu-PS interface, even if IPoA transmission is used, IP paths still need to be configured.  High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA) services can be carried on the same IP path, with HSDPA services carried in the downlink and HSUPA services carried in the uplink. 3.5 Networking Application 3.5.1 2G and 3G Networking The typical networking scenarios for the Iub interface are as follows:  Direct connection: The RNC is directly connected to a NodeB through a physical port, the bandwidth of which is exclusively occupied by this Iub interface.  Transmission aggregation: As shown in Figure 3-5, the Iub traffic volume of more than one NodeB is converged, for example, on the transport network or at the hub NodeB.  Bandwidth being variable: The bandwidth on the transport network might be variable. For example, the bandwidth of Asymmetric Digital Subscriber Line (ADSL) transmission is variable.  ATM&IP dual stack: Both ATM and IP transmission resources are available for one Iub interface so that the transmission cost is reduced.  Hybrid IP: Both high-QoS transmission (such as IP over E1) and low-QoS transmission (such as IP over FE) are applicable to one Iub interface so that differentiated management of services is implemented.  RAN sharing: Operators share the physical bandwidth. In this scenario, bandwidth should be reserved for each operator.  The typical networking scenarios for the Abis interface are similar to the Iub interface, except that networking scenarios such as dual stack, hybrid IP, and RAN sharing are not applied to the Abis interface.  For details about the 2G and 3G networking, see the IP BSS Feature Parameter Description of the GBSS and the IP RAN Feature Parameter Description of the RAN. Table 3-7 lists the types of transmission applicable to each interface. Table 3-7 Types of transmission applicable to each interface Interface ATM TDM HDLC IP ATM&IP Dual Stack Hybrid IP Iub √ - - √ √ √ Iur √ - - √ - - Iu-CS √ - - √ - - Iu-PS - - - √ - - Abis - √ √ √ - - A - √ - √ - - Ater - √ - √ - - Pb - √ - - - - Gb - √ - √ - - Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 3-12
  26. 26. SingleRAN Transmission Resource Management 3 Transmission Resources The IP transmission mode of the Ater interface supports only TDM networking on IP over E1. 3.5.2 Co-Transmission Networking Co-TRM is applied to the following co-transmission networking scenarios: Figure 3-7 Co-transmission scenario where the GSM BSC and the UMTS RNC are combined GSM+UMTS MBSC deployed and GSM+UMTS MBTSs deployed GSM+UMTS MBTS sharing IP LP transmission resources over the Abis and Iub interfaces Figure 3-8 Co-transmission scenario where the GSM BSC and the UMTS RNC are deployed separately BSC and RNC separately deployed, without sharing physical ports GSM+UMTS MBTS deployed, sharing physical ports For details about the co-transmission networking, see the Common Transmission Feature Parameter Description. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 3-13
  27. 27. SingleRAN Transmission Resource Management 4 Quality of Service 4 Quality of Service 4.1 Overview The purpose of TRM algorithms is to guarantee the Quality of Service (QoS). Different types of service have different QoS requirements.  The Iub or Abis control plane and the Uu signaling require reliable transmission. Packet loss rate and delay may affect KPIs such as connection delay, handover success rate, access success rate, and call drop rate.  CS services have requirements for delay and packet loss rate. For example, speech services are sensitive to end-to-end latency, and data services are sensitive to packet loss.  NRT services are relatively insensitive to delay, but in some scenarios, they are sensitive to delay. When the load is light, the requirement for delay should be fulfilled. whereas when the load is heavy, the requirement for delay can be lowered to a certain extent to guarantee the throughput. The transport layer provides various transport bearers and transport priorities. The appropriate type of transport bearer and transport priority should be selected according to the traffic classes, user priorities, traffic priorities, and radio bearer type of service. High-priority services take precedence in transmission when congestion occurs. This reduces packet loss and transmission delay. Transmission resource mapping maps services of different QoS requirements to different transport bearers. Transmission resource mapping (WRFD-050424 Traffic Priority Mapping onto Transmission Resources) is an important method to guarantee the QoS and differentiate the users and services. It mainly involves data in the user plane. This section describes transmission resource mapping and associated concepts such as transport priorities and service QoS. For the differences in implementing QoS-related services in the 2G TRM, 3G TRM, and Co-TRM, see the following sections. 4.2 Transport Priorities Transport priority-related concepts include Differentiated Service Code Point (DSCP), Virtual Local Area Network (VLAN) priority, and Priority Queue (PQ). 4.2.1 DSCP The DSCP is carried in the header of each IP packet to inform the nodes on the network of the QoS requirement. Through the DSCP, each router on the propagation path knows which type of service is required. DSCP provides differentiated services (DiffServ) for layer 3 (L3). When entering the network, services are differentiated and subject to flow control according to the QoS requirement. In addition, the DSCP fields of the packets are set. The DSCP field is in the header of each IP packet. On the network, DiffServ is applied to different types of traffic according to the DSCP values and services for the traffic are provided. The services include resource allocation, queue scheduling, and packet discard policies, which are collectively called PHB. All nodes within the DiffServ domain implement PHB according to the DSCP field in each packet. Policies for using DSCP are as follows:  The traffic carried on QoS paths uses the DSCPs mapped from services. For details, see "Mapping from TC to PHB or PVC" and "Mapping from PHB to DSCP."  The traffic carried on the non-QoS path uses the DSCP that the PHB of the IP path corresponds to. For details, see "Mapping from PHB to DSCP." Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 4-1
  28. 28. SingleRAN Transmission Resource Management 4 Quality of Service It is recommended that you set the path type to QoS path when configuring the IP path. This ensures simple configuration, better multiplexing, and higher QoS. 4.2.2 VLAN Priorities VLAN provides services of different priorities to isolate different users and enhance security of IP transport network. VLAN provides differentiated services for layer 2 (L2). The principles of VLAN priorities are similar in the 2G and 3G systems. This section takes the VLAN solution of the 3G system as an example. Figure 4-1 shows a typical example of the VLAN solution on the Iub interface. In this solution, the Multi-Service Transmission Platform Network (MSTP) provides two Ethernets carried on two different Virtual Channel (VC) trunks.  One Ethernet is a private network for RT services of multiple NodeBs. The RT services in this Ethernet are not affected by other services and thus used for carrying high-priority services.  The other Ethernet is a public network for NRT services of multiple NodeBs. It can be shared by other services. The NRT services in this Ethernet might be affected by other services and thus used for carrying low-priority services. Figure 4-1 Typical example of solution of the VLAN on the Iub interface Red line: private network Blue line: public network Black line: connection between routers Each NodeB or RNC provides an Ethernet port that connects to the MSTP network. The MSTP transmits the Ethernet data of different QoS to either of the VC trunks according to the VLAN priority in the frame header of Ethernet data. On the same VC trunk, different NodeB data is distinguished by VLANID. Figure 4-2 shows an example of using VLAN priorities. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 4-2
  29. 29. SingleRAN Transmission Resource Management 4 Quality of Service Figure 4-2 Example of using VLAN priorities The RNC, NodeB1, and NodeB2 are connected to the same L2 network. Data of NodeB1 (VLAN 10) and NodeB2 (VLAN 20) is isolated according to different VLANIDs. VLANIDs are attached to data of different traffic classes sent from the Ethernet port. Data of different traffic classes use VLAN priorities mapped from DSCP. Then, the L2 network provides differentiated services based on the VLAN priorities. When IP paths are configured, the VLANFLAG parameter specifies whether a VLAN is available. Table 4-1 describes the default mapping from DSCP to VLANPRI. Table 4-1 Default mapping from DSCP to VLANPRI DSCP VLANPRI 0-7 0 8-15 1 16-23 2 24-31 3 32-39 4 40-47 5 48-55 6 56-63 7 Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 4-3
  30. 30. SingleRAN Transmission Resource Management 4 Quality of Service You can run the SET DSCPMAP command to dynamically configure the mapping from DSCP to VLANPRI. 4.2.3 Priority Queues At each ATM port (such as IMA, UNI, fractional ATM, or NCOPT port) or leaf LP of the RNC, there are five types of priorities, as shown in Figure 4-3. The scheduling order is as follows: CBR > RT-VBR > UBR+ (MCR) > WRR (NRT-VBR, UBR) > UBR+ (non-MCR), where MCR refers to Minimum Cell Rate. Figure 4-3 Queues at each ATM port or leaf LP of the RNC At each IP port (such as PPP/MLPPP or Ethernet port) or leaf LP of the RNC, BSC or MBSC, there are six types of priorities, as shown in Figure 4-4. The default scheduling order is as follows: Queue1 > Queue2 > WRR (Queue3, Queue4, Queue5, and Queue6), where WRR refers to Weighted Round Robin. Figure 4-4 Queues at each IP port or leaf LP of the RNC Different types of services enter queues of different priorities for transmission. In this way, services are differentiated. For details, see section 4.4.3 "Mapping from Traffic Bearers to Transport Bearers." At each ATM port (such as IMA, UNI, fractional ATM, or NCOPT port) or LP of the NodeB, there are four types of priorities, as shown in Figure 4-5. The scheduling order is as follows: CBR or UBR+ (MCR) > RT-VBR > NRT-VBR > UBR or UBR+ (non-MCR). Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 4-4
  31. 31. SingleRAN Transmission Resource Management 4 Quality of Service Figure 4-5 Queues at each ATM port or LP of the NodeB At each IP port (such as PPP/MLPPP or Ethernet port) or LP of the NodeB, there are six types of priorities, as shown in Figure 4-6. The default scheduling order is as follows: Queue1 > WFQ (Queue2, Queue3, Queue4, Queue5, and Queue6). Where, WFQ refers to Weighted Fair Queuing. Figure 4-6 Queues at each IP port or LP of the NodeB Priority queues are used for RNC backpressure-based downlink congestion control. For details, see section 6.5.3 "RNC Backpressure-Based Downlink Congestion Control Algorithm." In the 2G TRM, there are no priority queues at the BTS. 4.2.4 Priority Queues and Rate Limiting in the NodeB The NodeB automatically configures priority queues (PQs). PQ and Rate Limiting (RL) supplement each other. When the actual bandwidth exceeds the specified bandwidth, the NodeB buffers or discards the congested data to ensure the bandwidth at the physical port. When the physical port is congested, the NodeB discards low-priority packets according to the PQ rules. Table 4-2 describes the PQ rules based on the Most Significant Bits (MSBs) of DSCP in the NodeB. Table 4-2 PQ rules in the NodeB MSB of DSCP PQ 110 or 111 Default urgent queue; manual configuration of PQ is not required. 101 TOP 100 or 011 MIDDLE 010 or 001 NORMAL 0 BOTTOM Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 4-5
  32. 32. SingleRAN Transmission Resource Management 4 Quality of Service Parameters associated with PQs in the NodeB are as follows:  SIGPRI  OMPRI  PTPPRI 4.3 Service QoS For service QoS, the following aspects need to be taken into consideration:  Traffic classes at the radio network layer: conversational service, streaming service, interactive service, and background service, which are in descending order of QoS requirement.  User priorities: Services of the same traffic class can be differentiated based on the ARP. − The radio access network (RAN) provides DiffServ for users with different priorities based on the Allocation Retention Priority (ARP). ARP is a core network (CN) QoS parameter regarding user priorities. − There are three user priorities, that is, gold, silver, and copper. The relation between user priority and ARP can be set through SET UUSERPRIORITY command. − Both 2G and 3G systems differentiate user priorities, but the 2G system uses the ARP for admission, and there is no mapping from user priority to ARP.  Traffic Handling Priority (THP): Interactive services of the same ARP can be differentiated based on the THP. THPs are classified into high priority, middle priority, and low priority. The transport network layer of the 2G system does not differentiate THPs.  Types of radio bearer: Radio bearers represent the service types of bearers, including R99 and HSPA (HSUPA and HSDPA). Interactive services of the same ARP and THP can be differentiated based on the parameter CarrierTypePriorInd. For details about user priorities and THP, see the Load Control Feature Parameter Description of the RAN. 4.4 Transmission Resource Mapping Transmission resource mapping refers to the mapping from traffic bearers to transport bearers. The RNC and BSC support configuration of mapping to transport bearers according to the characteristics of service QoS. 4.4.1 Traffic Bearers For 2G services, traffic bearers refer to the traffic class (TC) of the 2G system; for 3G services, traffic bearers refer to the combination of TC, ARP, THP, and type of radio bearer that corresponds to one transport bearer. The RNC provides the following traffic classes that can be used in transmission resource mapping configuration:  Common channel  SRB  SIP  AMR speech service  CS conversational service  CS streaming service Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 4-6
  33. 33. SingleRAN Transmission Resource Management  PS conversational service  PS streaming service  PS interactive service  4 Quality of Service PS background service The BSC provides the following traffic classes that can be used in transmission resource mapping configuration:  Abis OML  Abis RSL  Abis ESL  Abis EML  CS speech service  CS data service  PS data service 2G Abis signaling traffic classes have higher QoS requirement than other traffic classes, except Abis EML. 4.4.2 Transport Bearers Transport bearers refer to transmission of traffic on a certain type of paths. For details about the types of paths for transport bearers, see section 3.4 "Path Resources." Priorities of paths are the basis of transmission resource mapping:  Priorities of ATM paths are specified by the Pre-defined Virtual Connection (PVC).  Priorities of IP paths are specified by PHB. PHB is then indicated by the DSCP priority. 4.4.3 Mapping from Traffic Bearers to Transport Bearers Overview For the mapping from traffic bearers to transport bearers, default or dynamic configuration and adjacent-node-oriented or non-adjacent-node-oriented configuration are provided. The keyword used for configuring transmission resource mapping is traffic type. In transmission resource mapping:  For 2G services, each TC corresponds to one priority of transport bearer, as shown in Figure 4-7.  For 3G services, each combination of TC, ARP, THP, and type of radio bearer corresponds to one priority of transport bearer, as shown in Figure 4-8. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 4-7
  34. 34. SingleRAN Transmission Resource Management 4 Quality of Service  Only the mapping of Abis signaling services in the 2G system is non-adjacent-node-oriented configuration. For details, see "Mapping from Abis Signaling Traffic to Transmission Resources."  The transmission resource mapping of the RNC also supports configuration of primary and secondary paths. For details, see section 5.5 "Admission Control." Figure 4-7 2G transmission mapping Figure 4-8 3G transmission mapping Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 4-8
  35. 35. SingleRAN Transmission Resource Management 4 Quality of Service Mapping from TC to PHB or PVC For each combination of interface type and transport type, a transmission resource mapping can be configured by default. The RNC and BSC provide default transmission resource mapping tables (TRMMAP tables) for various networking scenarios. The default TRMMAP table can be queried through the LST TRMMAP command. Table 4-3 describes the default TRMMAP table, where IDs 0 to 8 represent Iub ATM, Iub IP, Iub ATM IP, Iub HYBRID IP, Iur ATM, Iur IP, Iu-CS ATM, Iu-CS IP, and Iu-PS of the RNC respectively, and IDs 10 to 12 represent Abis IP, A IP, and Ater IP of the BSC respectively. Table 4-3 Default TRMMAP table Interface ATM IP ATM&IP Dual Stack Hybrid IP Iub 0 1 2 3 Iur 4 5 - - Iu-CS 6 7 - - Iu-PS - 8 - - Abis - 10 - - A - 11 - - Ater - 12 - -  In HDLC transmission mode, traffic is directly mapped to port queues.  The default TRMMAP table differentiates neither operators nor user priorities. If transmission resource mapping is not dynamically configured, the default TRMMAP table is used. To provide better differentiated services, the RNC and BSC support dynamic configuration of the transmission resource mapping and thus traffic bearers can be mapped to transport bearers freely. The RNC also supports separate configuration of transmission resource mapping under an Iub adjacent node for a certain operator or a certain user priority. To dynamically configure transmission resource mapping, do as follows: Step 1 Run the ADD TRMMAP command to specify the mapping from the TCs of a specific interface type and transport type to a transport bearer. Step 2 Run the ADD ADJMAP command to use the configured TRMMAP table. When the RNC ADJMAP is configured, the TRMMAP tables need to be specified for gold, silver, and copper users respectively.  In the RAN sharing scenario, the operator index needs to be set to specify transmission resource mapping of the operator under the adjacent node, if the resource management mode is set to EXCLUSIVE.  When the transmission mode on the Iub interface is ATM&IP dual stack or hybrid IP, the load balance index of primary and secondary paths needs to be configured. ----End The associated parameters are as follows:  ITFT Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 4-9
  36. 36. SingleRAN Transmission Resource Management  TRANST  CNMNGMODE  CNOPINDEX  TMIGLD  TMISLV  TMIBRZ  LEIGLD  LEISLV  4 Quality of Service LEIBRZ Mapping from PHB to DSCP The service QoS can be mapped to transport QoS by configuring the mapping between PHB and DSCP. Table 4-4 describes the default mapping from PHB to DSCP. Table 4-4 Default mapping from PHB to DSCP PHB DSCP (Binary) DSCP (Decimal) EF 101110 46 AF43 100110 38 AF42 100100 36 AF41 100010 34 AF33 11110 30 AF32 11100 28 AF31 11010 26 AF23 10110 22 AF22 10100 20 AF21 10010 18 AF13 1110 14 AF12 1100 12 AF11 1010 10 BE 0 0 You can run the SET PHBMAP command to dynamically configure the mapping from PHB to DSCP (PHBMAP).  If the traffic is carried on a non-QoS path, the PHB of the path is determined by the path type. Run the SET PHBMAP command to configure PHBMAP.  If the traffic is carried on a QoS path, the PHB of the path is determined by the TRMMAP. Run the ADD TRMMAP command to determine the PHB of the path, and then run the SET PHBMAP command to configure PHBMAP. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 4-10
  37. 37. SingleRAN Transmission Resource Management 4 Quality of Service Mapping from DSCP to Queue Priority By configuring the mapping from DSCP to queue priority, you can achieve differentiated services for the traffic classes with different DSCP values according to different queue priorities. Table 4-5 describes the default mapping from DSCP to queue priority. Table 4-5 Default mapping from DSCP to queue priority Minimum DSCP Queue Priority 40 0 32 1 24 2 16 3 8 4 0 5 You can run the SET QUEUEMAP command to dynamically configure the minimum DSCP value that each queue at the IP port corresponds to. The associated parameters are as follows:  Q0MINDSCP  Q1MINDSCP  Q2MINDSCP  Q3MINDSCP  Q4MINDSCP The minimum DSCP value of queue 5 need not be set. The IP packet that meets the condition (0 <= DSCP value < minimum DSCP value for queue 4) enters queue 5 for transmission. Mapping from Abis Signaling Traffic to Transmission Resources You need to configure the mapping from Abis signaling traffic of the BSC to transmission resources independently. Both the default configuration and the dynamically configuration are available for the mapping. You can use the SET BSCABISPRIMAP command to dynamically configure the mapping. Table 4-6 and Table 4-7 describe the default mapping from traffic to transmission resources. Table 4-6 Mapping from traffic to transmission resources in IP transmission mode TC DSCP ESL 48 OML 48 RSL 48 EML 0 Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 4-11
  38. 38. SingleRAN Transmission Resource Management 4 Quality of Service Table 4-7 Mapping from traffic to transmission resources in HDLC transmission mode TC Queue Priority ESL 0 OML 0 RSL 0 EML 5 For IP transmission on the Abis interface, the associated parameters are as follows:  OMLDSCP  RSLDSCP  EMLDSCP  ESLDSCP For HDLC transmission on the Abis interface, the associated parameters are as follows:  OMLPRI  RSLPRI  EMLPRI  ESLPRI 4.5 Summary Table 4-8 describes the difference between traffic bearers in the 2G, 3G, and co-transmission systems. Table 4-8 Difference between traffic bearers in the 2G, 3G, and co-transmission systems Traffic Bearer 2G System 3G System Co-Transmission System TC √ √ √ ARP √ √ √ THP √ √ √ Radio bearer type × √ √  The 2G system uses the ARP for admission, and there is no mapping from user priority to ARP.  The transport layer of the 2G system does not differentiate THPs. Table 4-9 describes the adjacent-node-oriented transmission resource mapping of the 2G TRM, 3G TRM, and Co-TRM. Table 4-9 Adjacent-node-oriented transmission resource mapping of the 2G TRM, 3G TRM, and Co-TRM Transmission Mode Adjacent-Node-Oriented Transmission Resource Mapping 3G ATM transmission From TC + ARP + THP + radio bearer type to PVC 3G IP transmission Issue 03 (2011-09-30) From TC + ARP + THP + radio bearer type to PHB, from PHB to DSCP to queue priority Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 4-12
  39. 39. SingleRAN Transmission Resource Management 4 Quality of Service Transmission Mode Adjacent-Node-Oriented Transmission Resource Mapping 2G HDLC transmission From TC (excluding signaling traffic) to queue priority 2G IP transmission From TC (excluding signaling traffic) to PHB, from PHB to DSCP to queue priority Co-transmission  For 2G services: from TC (excluding signaling traffic) to PHB, from PHB to DSCP to queue priority  For 3G services: from TC + ARP + THP + radio bearer type to PHB, from PHB to DSCP to queue priority  The mapping from signaling traffic of the Abis interface of the 2G system to transmission resources is not oriented to adjacent nodes. It needs to be configured independently.  In TDM transmission mode of the 2G system, traffic is directly carried on the timeslot at the port. Thus, transmission resource mapping is not required.  In IP transmission mode of the 3G system, configuration of primary and secondary paths is also supported. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 4-13
  40. 40. SingleRAN Transmission Resource Management 5 Load Control 5 Load Control 5.1 Overview of Load Control Load control at the transport layer is used to manage transmission bandwidth and control transmission load, for the purpose of allowing more users to access the network and increasing the system capacity with the QoS guaranteed. Load control is responsible for management of data in the control plane. Load control methods include admission control, LDR, and OLC.  Admission control is the basic method of load control. In the process of transmission resource admission, admission control is used to determine whether the transmission resources are sufficient to accept the admission request from a user. Admission control prevents excessive admission of users and guarantees the quality of admitted services.  LDR is used to prevent congestion, reduce transmission load, and increase admission success rate and system capacity.  OLC is used to quickly eliminate overload when congestion occurs, and to reduce the impact of overload on high-priority users. Differentiated services are implemented as follows:  Admission strategies: Different admission strategies are used for different types of users. During admission based on transmission resources, differentiated services for user priorities are implemented.  Preemption: High-priority users preempt bandwidth of low-priority users. Thus, differentiated services for different service types and user priorities are implemented.  LDR: Different LDR actions are used for different services. During congestion, differentiated services for different service types are implemented.  OLC: Bandwidth of low-priority users is released, which reduces the impact of overload on high-priority users. In the case of overload, differentiated services for different service types and user priorities are implemented. Table 5-1 describes load control applied in the 2G TRM, 3G TRM, and Co-TRM. Table 5-1 Load control applied in the 2G TRM, 3G TRM, and Co-TRM Load Control 2G TRM 3G TRM Co-TRM Reserved bandwidth admission √ √ √ Load balancing - √ √ Preemption √ √ √ Queuing √ √ √ LDR √ √ √ OLC √ √ √ Admission control This section describes the definition and calculation of transmission load, calculation of reserved bandwidth, and load thresholds in addition to admission control, LDR, and OLC. For differences of implementing load control in the 2G TRM, 3G TRM, and Co-TRM, see the following sections. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 5-1
  41. 41. SingleRAN Transmission Resource Management 5 Load Control 5.2 Definition and Calculation of Transmission Load Transmission load refers to transmission resources required by access users. In the ATM, IP, or HDLC transmission mode, transmission resources are measured based on bandwidth, and load control management is based on transmission bandwidth only. Load is defined on the basis of reserved bandwidth. Bandwidth is reserved for each service in load control. Load is the sum of bandwidth reserved for all services, and the uplink load and downlink load are calculated separately. Load of all paths and all LPs (including leaf LPs and hub LPs) needs to be calculated as follows:  Path load: The load on a path is equal to the sum of reserved bandwidth of all services.  Leaf LP load: The load on a leaf LP is equal to the sum of load of all paths.  Hub LP load: The load on a hub LP is equal to the sum of load of all LPs. 5.3 Calculation of Reserved Bandwidth Reserved bandwidth is used for both load calculation and user admission. Therefore, calculation of reserved bandwidth for each service should be specified. 5.3.1 Calculation of Bandwidth Reserved for 2G Signaling This section describes the bandwidth reserved for signaling of the 2G Link Access Protocol on the D channel (LAPD) link. When the IP transmission mode is applied to the Abis interface, some LAPD links and user plane data share the transport channels. The LAPD links include OML, ESL, and RSL. These links occupies a large proportion of bandwidth and therefore the bandwidth of LPs needs to be reserved for LAPD links to prevent congestion. The calculation of bandwidth reserved for LAPD links is as follows:  Bandwidth reserved for uplink signaling = Average bandwidth for uplink OMLs and ESLs of the BTS + Number of TRXs x Average bandwidth for uplink RSLs of the BTS  Bandwidth reserved for downlink signaling = Average bandwidth for downlink OMLs and ESLs of the BTS + Number of TRXs x Average bandwidth for downlink RSLs of the BTS You can adjust the bandwidth reserved for LAPD signaling of the BTSs using Abis IP. The associated parameters are as follows:  OMLESLUL  OMLESLDL  RSLUL  RSLDL In IP over E1 mode, the bandwidth reserved for LAPD signaling takes effect on LPs. To ensure the accuracy of admission based on bandwidth for PPP and MLPPP links, you are advised to take one of the following measures: Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 5-2
  42. 42. SingleRAN Transmission Resource Management 5 Load Control  Configure LPs on the PPP or MLPPP links with the same bandwidth as the PPP or MLPPP links  Configure IP paths of the QoS type: Bandwidth of IP path = Bandwidth of PPP or MLPPP - Max (Bandwidth reserved for uplink signaling, Bandwidth reserved for downlink signaling) 5.3.2 Calculation of Bandwidth Reserved for Traffic Bandwidth reserved for a service = Transport-layer rate of the service x Activity factor, where the transport-layer rate of the service derives from the rate that the user applies for. The RNC or BSC calculates the reserved bandwidth based on the activity factor and performs admission control based on the reserved bandwidth. The bandwidth reservation policies for different services are as follows:  For RT services: Reserved bandwidth = MBR x Activity factor  For 3G NRT services: Reserved bandwidth = GBR x Activity factor  For 2G NRT PDCH services (with the backpressure switch disabled): Reserved bandwidth = MBR x Activity factor  3G signaling: − Admission of SRB at 3.4 kbit/s: The bandwidth for 3G SRB signaling is fixed at 3.4 kbit/s. This admission mode is applicable to R99, HSDPA, and HSUPA services. For R99 services, if the bandwidth of a transport channel varies between 3.4 kbit/s and 13.6 kbit/s, resource allocation and resource admission do not need to be performed again. − Admission  of IMS at the GBR 3G common channels: − Bandwidth reserved for E-FACH = GBR x Activity factor − Bandwidth reserved for other common channels = MBR x Activity factor NOTE  For 2G PS services, the recommended activity factor is 1.  For 3G common channels or SRBs, the activity factors are identical for all users, instead of varying according to user priorities.  In TDM transmission mode, the bandwidth is allocated in a fixed manner instead of based on activity factors. Activity factors can be configured for different types of services and adjacent nodes:  Both default configuration and dynamic configuration are available for activity factors for different types of service. The default configuration can be queried through the LST TRMFACTOR command. You can run the ADD TRMFACTOR command to dynamically configure activity factors for different types of service.  You can run the ADD ADJMAP command to configure the same activity factor table for an adjacent node by specifying the FTI parameter. For 3G BE services, the GBR can be set by running the SET UUSERGBR command, according to traffic classes, traffic priorities, user priorities, and types of radio bearers. The associated parameters are as follows:  TrafficClass  THPClass  BearType  UserPriority  UlGBR  DlGBR Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 5-3
  43. 43. SingleRAN Transmission Resource Management 5 Load Control 5.4 Load Thresholds In the admission process based on transmission resources, load and threshold are compared to determine whether the admission is successful. The thresholds can be configured through the parameters such as relative residual resource (%, percentage of residual bandwidth to total bandwidth) or absolute residual resource (kbit/s, residual bandwidth). Uplink and downlink thresholds are configured separately.  Admission threshold of a new user (handover reserved threshold) This threshold controls the admission of a new user and can be configured through the parameters FWDRSVHOBW, BWDRSVHOBW, FWDRESVHOTH, and BWDRESVHOTH.  Congestion threshold (admission threshold of a user requesting a rate increase) This threshold triggers LDR and can be configured through the parameters FWDCONGBW, BWDCONGBW, FWDCONGTH, and BWDCONGTH.  Congestion clear threshold This threshold clears congestion and can be configured through the parameters FWDCONGCLRBW, BWDCONGCLRBW, FWDCONGCLRTH, and BWDCONGCLRTH.  Overload threshold This threshold triggers overload control and can be configured through the parameters FWDOVLDRSVBW, BWDOVLDRSVBW, FWDOVLDTH, and BWDOVLDTH.  Overload clear threshold This threshold clears overload and can be configured through the parameters FWDOVLDCLRRSVBW, BWDOVLDCLRRSVBW, FWDOVLDCLRTH, and BWDOVLDCLRTH. NOTE In 2G TDM transmission mode, there are only congestion threshold and congestion clear threshold, which are configured through the parameters TDMCONGTH and TDMCONGCLRTH. The congestion threshold and congestion clear threshold, and the overload threshold and overload clear threshold are used to prevent ping-pong effect. It is recommended that they should be set to different values. By running the ADD TRMLOADTH command, you can configure a load threshold table (TRMLOADTH table) for paths, LPs, resource groups, or physical ports. By specifying the TRMLOADTHINDEX parameter, the TRMLOADTH table can be referred to. In ATM transmission, you can run the MML command ADD AAL2PATH or ADD ATMLOGICPORT command to refer to the TRMLOADTH table. In IP transmission, you can run the MML command ADD IPPATH or ADD IPLOGICPORT command to refer to the TRMLOADTH table. In TDM/HDLC transmission, you can run the MML command SET BSCABISPRIMAP to refer to the TRMLOADTH table. For details about the preceding thresholds, see sections 5.5 "Admission Control" and 5.6 "Load Reshuffling and Overload Control." 5.5 Admission Control Admission control is used to determine whether the transmission resources are sufficient to accept the admission request from a user. If the transmission resources are sufficient, the admission request is admitted; otherwise, the request is rejected. Admission control can prevent admission of excessive users and guarantee the QoS. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 5-4
  44. 44. SingleRAN Transmission Resource Management 5 Load Control 5.5.1 Admission Process Figure 5-1 shows the admission control during the request for transmission resources. Figure 5-1 Admission control during the request for transmission resources As shown in Figure 5-1, when the users request transmission resources, the admission control process is as follows: 1. The admission based on transmission resources is decided according to the admission strategy. If the admission is successful, a user can obtain transmission resources. If the admission fails, go to step 2. For details about the admission strategy, see section 5.5.2 "Admission Strategy." 2. The attempt to preempt resources is made. If the preemption is successful, a user can obtain transmission resources. If the preemption fails or the preemption function is not supported, go to step 3. For details about preemption, see section 5.5.5 "Preemption." 3. The attempt for queuing is made. If the queuing is successful, a user can obtain transmission resources. If the queuing fails or the queuing function is not supported, the admission based on transmission resources fails. For details about queuing, see section 5.5.6 "Queuing." After transmission resources are successfully admitted, bandwidth needs to be reserved on the corresponding paths and ports. In addition, bandwidth needs to be updated to the load. 5.5.2 Admission Strategy Overview The principles of ATM/IP transmission resource admission are as follows: Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 5-5
  45. 45. SingleRAN Transmission Resource Management 5 Load Control  Multiple levels of admission. After the user initiates a request for transmission resources, admission based on transmission resources is decided in the sequence of paths -> LPs -> physical ports.  If a certain level of admission is not supported, you can directly perform the admission decision of transmission resources of the next level. If the LP is not configured, the admission is performed in the sequence of paths -> physical ports.  In multiple levels of admission, users can obtain transmission resources only when the admission based on all resources is successful.  In TDM Flex Abis transmission, the transmission resource admission is performed from the Flex Abis resources of the lowest-level base station step by step in an ascending order. In HDLC transmission, admission is based on HDLC links.  The service priorities need to be taken into consideration. New users, handover users, and users requesting a rate increase use different admission strategies. The admission based on transmission resources is determined according to the current load, bandwidth requested by users, and admission thresholds. The admission strategy varies according to the types of users.  For a new user − Admission based on paths Path load + Bandwidth required by the user < Total configured bandwidth for the path - Path bandwidth reserved for handover. − Admission based on LPs The admission based on LPs is performed level by level. For each level of admission, the strategy is as follows: LP load + Bandwidth required by the user < Total bandwidth for the LP - LP bandwidth reserved for handover.  For a handover user − Admission based on paths Path load + Bandwidth required by the user < Total bandwidth for the path. − Admission based on LPs The admission based on LP resources is performed level by level. For each level of admission, the strategy is as follows: LP load + Bandwidth required by the user < Total bandwidth for the LP.  For a user requesting a rate increase − Admission based on paths Path load + Bandwidth required by the user < Total bandwidth for the path - Path congestion threshold. − Admission based on LPs The admission based on LPs is performed level by level. For each level of admission, the strategy is as follows: LP load + Bandwidth required by the user < Total bandwidth for the LP - LP congestion threshold. NOTE If no admission threshold is configured for the user, the admission strategy can be simplified as: Load + Bandwidth required by the user < Total bandwidth configured. Procedure for the Admission Based on Paths One type of service can be mapped to multiple paths of the same type by configuring transmission resource mapping. Figure 5-2 shows the procedure for the admission based on paths. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 5-6
  46. 46. SingleRAN Transmission Resource Management 5 Load Control Figure 5-2 Procedure for the admission based on paths Step 1 Paths are selected according to transmission resource mapping. For details about transmission resource mapping, see section 4.4 "Transmission Resource Mapping." If no paths are available for use, for example, when the mapped path type does not exist, the admission fails. Step 2 The admission sequence for all paths is determined. For details, see the section "Sequence of the Admission Based on Paths." Step 3 According to the sequence, a path is selected to undergo admission decision. If… Then… The admission succeeds. The admission based on paths is complete. The admission fails. Go to Step 4. Step 4 Whether there are still available paths is determined. If… Then… There is no available path. The admission fails, the admission based on paths is complete. There are still available paths. Go to Step 3. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 5-7
  47. 47. SingleRAN Transmission Resource Management 5 Load Control Sequence of the Admission Based on Paths During the admission process, the sequence of the admission based on the paths needs to be determined after all paths available for a type of service are determined.  If the type of service requests a rate decrease, successful admission is directly performed on its original path.  If the type of service requests a rate increase, an admission decision is preferentially performed on its original path.  If a type of service is mapped to multiple paths of the same type, − When paths are configured as primary and secondary paths and load balancing algorithm is enabled, firstly whether the admission is based on the primary paths or the secondary paths is determined according to the algorithm of path load balancing. For details, see section 5.5.4 "Load Balancing." Then the specific primary or secondary path to undergo admission decision is determined according to the algorithm of path load sharing. For details, see section 5.5.3 "Load Sharing." − Otherwise, the path to undergo admission decision is determined according to the algorithm of path load sharing. For details, see section 5.5.3 "Load Sharing." 5.5.3 Load Sharing As Figure 5-3 shows, the round robin path algorithm helps implement load sharing between paths.  One type of service can be mapped to multiple paths of the same type. The paths form a circular chain. In the circular chain, the admission sequence for all paths is fixed.  A cursor is used to indicate the current path for admission decision.  If the admission succeeds, the cursor moves to the next path for use in the next admission procedure.  If the admission fails, the next path is chosen to undergo admission decision in the sequence of the circular chain. Figure 5-3 Path round robin For example,  One type of service is mapped to five paths of the same type that are numbered path 1 to path 5. The five paths form a circular chain: 1→2→3→4→5→1.  Assume that the type of service needs to be admitted for 100 times in response to 100 requests. The times are respectively marked T1, T2, T3, …  Assume that the admission of T1 succeeds on path 1. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 5-8
  48. 48. SingleRAN Transmission Resource Management 5 Load Control  Then the admission of T2 is performed in the sequence of 2→3→4→5→1. Assume that the admission succeeds on path 4.  Then the admission of T3 is performed in the sequence of 5→1→2→3→4. Assume that the admission fails on all paths. In this case, the admission of T3 is rejected.  Then the admission of T4 is performed in the sequence of 5→1→2→3→4. … If the admission of all the 100 times succeeds on the first path for admission decision, then the 100 service requests are respectively admitted on one of the five paths in the following way: 5.5.4 Load Balancing In the admission control, load balancing is a method used to achieve the load balance between primary and secondary paths. Principles of Load Balancing The principles of load balancing are as follows:  Load balancing between primary and secondary paths is applied only in the Iub hybrid transmission scenario, including ATM&IP dual stack and hybrid IP transmission.  A service is not always preferably admitted based on the primary path. If the load of the primary path exceeds the load threshold and the ratio of secondary path load to primary path load is lower than the load ratio threshold, then the service is preferably admitted based on the secondary path to improve the resource usage and user experience. Calculation of the Load of Primary and Secondary Paths The load of a path is calculated as follows: PathLoad = (PortUsed ÷ PortAvailable) x 100% where:  PathLoad refers to the load of the path.  PortUsed refers to the total bandwidth of the admitted services at the physical port.  PortAvailable refers to the total available bandwidth at the physical port, including the used bandwidth. Issue 03 (2011-09-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd 5-9

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