Network Working Group J. Dunn
Request for Comments: 3134 C. Martin
Category: Informational ANC, Inc.
June 2001
Network Working Group J. Dunn
Request for Comments: 3134 C. Martin
Category: Informational ANC, Inc.
June 2001
Terminology for ATM ABR Benchmarking
ATM ABR基准测试术语
Status of this Memo
本备忘录的状况
This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
本备忘录为互联网社区提供信息。它没有规定任何类型的互联网标准。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (C) The Internet Society (2001). All Rights Reserved.
版权所有（C）互联网协会（2001年）。版权所有。
Abstract
摘要
This memo discusses and defines terms associated with performance benchmarking tests and the results of these tests in the context of Asynchronous Transfer Mode (ATM) based switching devices supporting ABR (Available Bit Rate). The terms defined in this memo will be used in addition to terms defined in RFCs 1242, 2285, and 2544 and 2761. This memo is a product of the Benchmarking Methodology Working Group (BMWG) of the Internet Engineering Task Force (IETF).
本备忘录讨论并定义了与支持ABR（可用比特率）的基于异步传输模式（ATM）的交换设备的性能基准测试相关的术语以及这些测试的结果。除RFCs 1242、2285、2544和2761中定义的术语外，还将使用本备忘录中定义的术语。本备忘录是互联网工程任务组（IETF）基准方法工作组（BMWG）的产品。
This document provides terminology for benchmarking ATM based switching devices supporting ABR. It extends terminology already defined for benchmarking network interconnect devices in RFC's 1242, 2285, and 2544 and 2761. Although some of the definitions in this memo may be applicable to a broader group of network interconnect devices, the primary focus of the terminology in this memo is on ATM ABR.
本文档提供了支持ABR的基于ATM的交换设备基准测试术语。它扩展了RFC的1242、2285、2544和2761中已经定义的网络互连设备基准测试术语。尽管本备忘录中的一些定义可能适用于更广泛的网络互连设备组，但本备忘录中术语的主要重点是ATM ABR。
This memo contains two major sections: Background and Definitions. The background section provides the reader with an overview of the technology and IETF formalisms. The definitions section is split into two sub-sections. The formal definitions sub-section is provided as a courtesy to the reader. The measurement definitions sub-section contains performance metrics with inherent units.
本备忘录包含两个主要部分：背景和定义。背景部分向读者概述了该技术和IETF形式。“定义”部分分为两个子部分。提供正式定义小节是为了向读者表示礼貌。“度量定义”小节包含具有固有单位的性能度量。
This document assumes that necessary services are available and active. For example, IP connectivity requires SSCOP connectivity between signaling entities. Further, it is assumed that the SUT has
本文档假设必要的服务可用且处于活动状态。例如，IP连接需要信令实体之间的SSCOP连接。此外，假设SUT具有
the ability to configure ATM addresses (via hard coded addresses, ILMI or PNNI neighbor discovery), has the ability to run SSCOP, and has the ability to perform signaled call setups (via UNI or PNNI signaling). Finally, this document presents only the terminology associated with benchmarking IP performance over ATM; therefore, it does not represent a total compilation of ATM test terminology.
能够配置ATM地址（通过硬编码地址、ILMI或PNNI邻居发现），能够运行SSCOP，并能够执行信号呼叫设置（通过UNI或PNNI信号）。最后，本文档仅介绍与ATM上IP性能基准测试相关的术语；因此，它并不代表ATM测试术语的全部汇编。
The BMWG produces two major classes of documents: Benchmarking Terminology documents and Benchmarking Methodology documents. The Terminology documents present the benchmarks and other related terms. The Methodology documents define the procedures required to collect the benchmarks cited in the corresponding Terminology documents.
BMWG产生两大类文件：基准术语文件和基准方法文件。术语文件介绍了基准和其他相关术语。方法文件规定了收集相应术语文件中引用的基准所需的程序。
2. Existing Definitions.
2. 现有定义。
RFC 1242, "Benchmarking Terminology for Network Interconnect Devices", should be consulted before attempting to make use of this document. RFC 2544, "Benchmarking Methodology for Network Interconnect Devices", contains discussions of a number of terms relevant to the benchmarking of switching devices and should be consulted. RFC 2285, "Benchmarking Terminology for LAN Switching Devices", contains a number of terms pertaining to traffic distributions and datagram interarrival. RFC 2761, "Terminology for ATM Benchmarking", contains a number terms pertaining to traffic management [TM4.0, TM4.1]. Many of the metrics defined in RFC 2761 (e.g., CDV, CER, CLR, CMR, and CTD) also apply to ABR performance benchmarking. These metrics will not be redefined in this document. For the sake of clarity and continuity, this RFC adopts the template for definitions set out in Section 2 of RFC 1242.
在尝试使用本文件之前，应参考RFC 1242“网络互连设备的基准术语”。RFC 2544，“网络互连设备的基准测试方法”，包含了与交换设备基准测试相关的许多术语的讨论，应参考。RFC 2285，“LAN交换设备的基准术语”，包含了许多与流量分布和数据报到达间隔相关的术语。RFC 2761，“ATM基准测试术语”包含与流量管理相关的一些术语[TM4.0，TM4.1]。RFC 2761中定义的许多指标（例如CDV、CER、CLR、CMR和CTD）也适用于ABR性能基准测试。这些指标将不会在本文档中重新定义。为了清晰和连续性，本RFC采用RFC 1242第2节规定的定义模板。
II. Definitions
二,。定义
The definitions presented in this section have been divided into two groups. The first group is formal definitions, which are required in the definitions of the performance metrics but are not themselves strictly metrics. These definitions are subsumed from other work done in other working groups both inside and outside the IETF. They are provided as a courtesy to the reader.
本节中给出的定义分为两组。第一组是正式定义，这些定义在性能指标的定义中是必需的，但它们本身并不是严格意义上的指标。这些定义包含在IETF内外其他工作组的其他工作中。它们是作为对读者的礼貌而提供的。
Term to be defined.
待定义的术语。
Definition: The specific definition for the term.
定义：该术语的具体定义。
Discussion: A brief discussion of the term, its application and any restrictions on measurement procedures.
讨论：简要讨论该术语、其应用和对测量程序的任何限制。
Specification: The working group and document in which the terms are specified and are listed in the references section.
规范：工作组和文件，其中规定了术语，并在参考资料部分列出。
1.2. Related Definitions.
1.2. 相关定义。
Definition: An ABR service parameter, ACR is the current rate (cells/second) at which a source is allowed to send.
定义：ABR服务参数，ACR是允许源发送的当前速率（单元/秒）。
Discussion: For ABR traffic, ACR constitutes the actual data throughput for a particular VC. The time change of this value effects TCP round trip time calculations, which in turn effects TCP throughput.
讨论：对于ABR流量，ACR构成特定VC的实际数据吞吐量。此值的时间变化会影响TCP往返时间计算，进而影响TCP吞吐量。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: This is the time permitted between sending RM-cells before the rate is decreased to ICR (Initial Cell Rate). The time units are .01 to 10.23 seconds with a granularity of 10 ms.
定义：这是在速率降低到ICR（初始信元速率）之前发送RM信元之间允许的时间。时间单位为0.01到10.23秒，粒度为10毫秒。
Discussion: For ABR traffic, ADTF constitutes the time rate of the ACR. This value effects TCP round trip time calculations, which in turn effects TCP throughput.
讨论：对于ABR业务，ADTF构成ACR的时间速率。该值影响TCP往返时间计算，进而影响TCP吞吐量。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: An ABR service parameter, AIR controls the rate at which the cell transmission rate increases. It is signaled as AIRF, where
定义：ABR服务参数AIR控制小区传输速率增加的速率。它的信号是AIRF，其中
AIRF = AIR*Nrm/PCR.
空气流量=空气流量*Nrm/PCR。
Discussion: For ABR traffic, AIR effects the time rate of change of the ACR. This value effects TCP round trip time calculations, which in turn effects TCP throughput.
讨论：对于ABR业务，空气影响ACR的时间变化率。该值影响TCP往返时间计算，进而影响TCP吞吐量。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: Refer to AIR.
定义：指空气。
Discussion: Refer to AIR.
讨论：参考空气。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: ABR is an ATM layer service category for which the limiting ATM layer transfer characteristics provided by the network may change subsequent to connection establishment. A flow control mechanism is specified which supports several types of feedback to control the source rate in response to changing ATM layer transfer characteristics.
定义：ABR是一种ATM层服务类别，网络提供的限制性ATM层传输特性可能在连接建立后发生变化。指定了一种流量控制机制，该机制支持多种类型的反馈，以控制源速率以响应不断变化的ATM层传输特性。
Discussion: It is expected that an end-system that adapts its traffic in accordance with the feedback will experience a low cell loss ratio and obtain a fair share of the available bandwidth according to a network specific allocation policy. Cell delay variation is not controlled in this service, although admitted cells are not delayed unnecessarily.
讨论：预期根据反馈调整其流量的终端系统将经历低信元丢失率，并根据特定于网络的分配策略获得公平的可用带宽份额。在该服务中，小区延迟变化不受控制，尽管接收的小区没有不必要的延迟。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: ABR connection conformance refers to the behavior specified for ABR destination and switches, but allows for delays between the source and the UNI [UNI3.1, UNI4.0], which may perturb the traffic flow.
定义：ABR连接一致性是指为ABR目的地和交换机指定的行为，但允许源和UNI之间的延迟[UNI3.1，UNI4.0]，这可能会干扰交通流。
Discussion: The cells on an ABR connection applies to CLP=0 cells, which are tested upon arrival. At the arrival point, each cell is identified as conforming or non-conforming. The minimal conformance definition for ABR is GCRA((1/PCR),t1), where PCR is defined for CLP=0 flow.
讨论：ABR连接上的小区适用于CLP=0的小区，在到达时进行测试。在到达点，每个单元被标识为合格或不合格。ABR的最低合规性定义为GCRA（（1/PCR），t1），其中PCR定义为CLP=0流量。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: The BN bit in the RM-cell indicated whether the RM-cell is a BECN cell or not.
定义：RM单元中的BN位表示RM单元是否为BECN单元。
Discussion: If BN=0, the RM cells were generated by the source. If BN=1, the RM cells were generated by the destination or a switch.
讨论：如果BN=0，则RM单元由源生成。如果BN=1，则RM单元由目标或交换机生成。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: The CCR field in the RM-cell is set by the source to its current ACR. CCR is formatted as a rate.
定义：RM单元中的CCR字段由源设置为其当前ACR。CCR的格式为速率。
Discussion: For BECN cells, CCR=0.
讨论：对于BECN电池，CCR=0。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: Cell blocks are a sequence of N cells transmitted consecutively on a given connection.
定义：小区块是在给定连接上连续传输的N个小区的序列。
Discussion: A cell block will normally correspond to the number of information cells transmitted between successive OAM cells.
讨论：小区块通常对应于连续OAM小区之间传输的信息小区数量。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: The CI bit in the RM-cell allows a network element to indicate that there is congestion in the network.
定义：RM单元中的CI位允许网元指示网络中存在拥塞。
Discussion: When the source receives a backward RM-cell with CI=1, ACR is decreased. When the destination turns around a forward RM-cell, the CI is set to 1 to indicate that the previously received data cell had the EFCI state set.
讨论：当源接收到CI=1的反向RM单元时，ACR降低。当目的地绕过转发RM单元时，CI设置为1，以指示先前接收的数据单元已设置EFCI状态。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: CDF controls the decrease in ACR (Allowed Cell Rate) associated with CRM (missing RM cell count).
定义：CDF控制与CRM（缺少RM单元格计数）相关的ACR（允许的单元格速率）的减少。
Discussion: For ABR traffic, CDF effects the time rate of change of the ACR. This value effects TCP round trip time calculations, which in turn effects TCP throughput.
讨论：对于ABR业务，CDF影响ACR的时间变化率。该值影响TCP往返时间计算，进而影响TCP吞吐量。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: The DIR bit in the RM-cell indicates which direction of data flow is associated with the RM-cell. DIR is changed from 0 to 1 when an RM-cell is turned around at the destination.
定义：RM单元中的DIR位指示数据流的哪个方向与RM单元相关联。当RM单元在目标位置掉头时，DIR从0更改为1。
Discussion: A forward RM-cell is indicated by DIR=0 and is associated with data cells flowing in the same direction. A backward RM-cell is indicated by DIR=1 and is associated with data cells flowing in the opposite direction.
讨论：正向RM单元由DIR=0表示，并与沿同一方向流动的数据单元相关联。向后的RM单元由DIR=1表示，并与反向流动的数据单元相关联。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: The ER field in the RM-cell is used to limit the source ACR to a specific value. For each RM-cell, ER is set by the source to a requested rate (e.g., PCR). It may be reduced by any network element in the path to a value that the element can sustain. ER is formatted as a rate.
定义：RM单元格中的ER字段用于将源ACR限制为特定值。对于每个RM单元，ER由源设置为请求的速率（例如PCR）。它可以被路径中的任何网络元素减少到该元素可以维持的值。ER被格式化为速率。
Discussion: None.
讨论：无。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: Information carried in the backward RM-cells provided by the network elements and/or the destination back to the source.
定义：由网元和/或目的地提供的反向RM单元中携带的信息返回到源。
Discussion: Feedback may include information in the ER field, or the CI or NI bits of each backward RM-cell.
讨论：反馈可能包括ER字段中的信息，或每个反向RM单元的CI或NI位。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: The transmission time for ABR CLP=0 cells, if the difference between itself and the transmission time for the previous CLP=0 cell on the connection is greater than or equal to the minimum: a) the inverse of the ACR in effect immediately after the transmission time of the first of the two cells b) the inverse of the ACR in effect immediately before the transmission time of the second of the two cells.
定义：ABR CLP的传输时间=0个小区，如果连接上的前一个CLP=0小区的自身和传输时间之差大于或等于最小值：a）两个小区中第一个小区的传输时间之后立即生效的ACR的倒数b）第二个小区的传输时间之前立即生效的ACR的倒数两个细胞。
Discussion: The transmission time for the first cell on the connection is automatically an ITT.
讨论：连接上第一个小区的传输时间自动为ITT。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: An ABR service parameter, in cells/sec, that is the rate at which a source should send initially and after an idle period.
定义：ABR服务参数，单位为cells/sec，即信源在初始和空闲时间后应发送的速率。
Discussion: none.
讨论：无。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: In-Rate ABR cells are sent with CLP=0.
定义：以CLP=0的速率发送ABR单元。
Discussion: ABR RM-cells shall be sent with CLP=0 except in certain circumstances, See Out-of-Rate Cells. All other ABR cells shall be sent with CLP=0.
讨论：ABR RM信元应以CLP=0发送，除非在某些情况下，请参阅速率信元外。所有其他ABR单元应以CLP=0发送。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: An ABR service traffic descriptor, in cells/sec, that is the rate at which the source is always allowed to send.
定义：ABR服务流量描述符，单位为cells/sec，即始终允许源发送的速率。
Discussion: MCR may be set to zero. The bandwidth available from the network may vary, but shall not become less than MCR.
讨论：MCR可设置为零。网络可用带宽可能有所不同，但不得小于MCR。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: An ABR service parameter that controls allocation of bandwidth between forward W-cells, backward RM-cells, and data cells.
定义：ABR服务参数，用于控制前向W小区、后向RM小区和数据小区之间的带宽分配。
Discussion: none.
讨论：无。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: The NI bit in the RM-cell is used to prevent a source from increasing its ACR. NI does not require any decrease in value.
定义：RM单元中的NI位用于防止源增加其ACR。NI不需要任何值的减少。
Discussion: None.
讨论：无。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: An ABR service parameter, Nrm is the maximum number of cells a source may send for each forward RM-cell.
定义：一个ABR服务参数，Nrm是一个信源可以为每个前向RM信元发送的最大信元数。
Discussion: none.
讨论：无。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: Out-of-Rate ABR cells are sent with CLP=1.
定义：在CLP=1的情况下发送超速率ABR单元。
Discussion: This may be used to enable a rate increase for a connection that has an ACR=0. The source would generate out-of-rate cells to probe the network to learn when it may increase its rate.
讨论：这可用于为ACR=0的连接增加速率。该源将生成速率外的单元来探测网络，以了解网络何时可能增加速率。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: An ABR service parameter, RDF controls the decrease in the cell transmission rate. RDF is a power of 2 from 1/32,768 to 1.
定义：作为ABR业务参数，RDF控制小区传输速率的降低。RDF是从1/32768到1的2的幂。
Discussion: For ABR traffic, RDF effects the time rate of change of the ACR. This value effects TCP round trip time calculations, which in turn effects TCP throughput.
讨论：对于ABR业务，RDF影响ACR的时间变化率。该值影响TCP往返时间计算，进而影响TCP吞吐量。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: This controls the amount by which the cell transmission rate may increase upon receipt of a RM-cell. The additive increase rate AIR=PCR*RIF. RIF is a power of 2, ranging from 1/32,768 to 1.
定义：这控制接收RM小区时小区传输速率可能增加的量。添加剂增加率空气=PCR*RIF。RIF是2的幂，范围从1/32768到1。
Discussion: For ABR traffic, RIF effects the time rate of change of the ACR. This value effects TCP round trip time calculations, which in turn effects TCP throughput.
讨论：对于ABR业务，RIF影响ACR的时间变化率。该值影响TCP往返时间计算，进而影响TCP吞吐量。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: RM cells are used to convey network status (available bandwidth, congestion levels) and request peak cell rates for ATM blocks. The RM cell has the following format:
定义：RM信元用于传输网络状态（可用带宽、拥塞级别）和请求ATM块的峰值信元速率。RM单元格具有以下格式：
Header: 5 bytes, same as the ATM cell header Protocol ID: 3 bytes, protocol ID value is 1 for ABR service Function specific field: 45 bytes, data required for the specific protocol (See DIR, BN, CI, NI, ER, CCR, and MCR for field information.) Rsvd: 6 bytes, reserved for future specification EDC: 10 bytes, CRC-10 error detection code computed over the cell payload .ti6 (except the CRC-10 field) and used to check for data corruption
报头：5个字节，与ATM信元报头协议ID相同：3个字节，协议ID值为1，用于ABR服务功能特定字段：45个字节，特定协议所需的数据（有关字段信息，请参阅DIR、BN、CI、NI、ER、CCR和MCR）。Rsvd:6个字节，保留用于未来规范EDC:10个字节，CRC-10错误检测码，通过小区有效载荷.ti6（CRC-10字段除外）计算，用于检查数据是否损坏
Discussion: RM information can exist at the VP and/or VC level. VP level cells are identified with a VCI value of 6. VC level cells are identified with a PT of 6. See DIR, BN, CI, NI, ER, CCR, and MCR for additional protocol field information.
讨论：RM信息可以存在于VP和/或VC级别。VP级单元的VCI值为6。VC级细胞的PT为6。更多协议字段信息，请参见DIR、BN、CI、NI、ER、CCR和MCR。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: A severely cell block outcome occurs when more than M errored cells, lost cells, or misinserted cell outcomes are observed in a received cell block.
定义：当在接收到的细胞块中观察到超过M个错误的细胞、丢失的细胞或错误插入的细胞结果时，就会出现严重的细胞块结果。
Discussion: none.
讨论：无。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: An ABR service parameter, TCR limits the rate at which a source may send out-of-rate forward RM-cells. TCR is a constant fixed at 10 cells/second.
定义：作为ABR服务参数，TCR限制了信源可能发送速率转发RM小区的速率。TCR是一个固定在10个单元/秒的常数。
Discussion: none.
讨论：无。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: An ABR service parameter, TDF controls the decrease in ACR associated with TOF. TDF is signaled as TDFF, where TDF=TDFF/RDF times the smallest power of 2 greater or equal to PCR. TDF is in units of 1/seconds.
定义：作为ABR服务参数，TDF控制与TOF相关的ACR的减少。TDF信号为TDFF，其中TDF=TDFF/RDF乘以大于或等于PCR的最小功率2。TDF的单位为1/秒。
Discussion: For ABR traffic, TDF effects the time rate of change of the ACR. This value effects TCP round trip time calculations, which in turn effects TCP throughput.
讨论：对于ABR业务，TDF影响ACR的时间变化率。该值影响TCP往返时间计算，进而影响TCP吞吐量。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: Refer to TDF. TDFF is either zero or a power of two in the range 1/64 to 1 in units of 1 /cells.
定义：参考TDF。TDFF为0或2的幂，范围为1/64至1，单位为1/单元。
Discussion: Refer to TDF.
讨论：参考TDF。
Specification: AF-TM4.0
规格：AF-TM4.0
1.2.30. Time Out Factor (TOF)
1.2.30. 超时系数（TOF）
Definition: An ABR service parameter, TOF controls the maximum time permitted between sending forward RM-cells before a rate decrease is required. It is signaled as TOFF where TOF=TOFF+1. TOFF is a power of 2 in the range: 1/8 to 4,096.
定义：ABR服务参数TOF控制在需要降低速率之前发送前向RM小区之间允许的最大时间。信号为TOFF，其中TOF=TOFF+1。TOFF是范围为1/8到4096的2的幂。
Discussion: For ABR traffic, TOF effects the time rate of change of the ACR. This value effects TCP round trip time calculations, which in turn effects TCP throughput.
讨论：对于ABR业务，TOF影响ACR的时间变化率。该值影响TCP往返时间计算，进而影响TCP吞吐量。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: Refer to TOF.
定义：指飞行时间。
Discussion: none.
讨论：无。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: An ABR service parameter that provides an upper bound on the time between forward RM-cells for an active source. It is 100 times a power of two with a range of 100*2-7 to 100*20
定义：一个ABR服务参数，为活动源的前向RM小区之间的时间提供上限。它是2的幂的100倍，范围为100*2-7到100*20
Discussion: For ABR traffic, Trm effects the time rate of change of the ACR. This value effects TCP round trip time calculations, which in turn effects TCP throughput.
讨论：对于ABR业务，Trm影响ACR的时间变化率。该值影响TCP往返时间计算，进而影响TCP吞吐量。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: An ABR connection may be divided into two or more separately controlled ABR segments. Each ABR control segment, except the first, is sourced by a virtual source. A virtual source implements the behavior of an ABR source endpoint. Backward RM-cells
定义：ABR连接可分为两个或多个单独控制的ABR段。除第一个ABR控制段外，每个ABR控制段均由虚拟源提供。虚拟源实现ABR源端点的行为。反向RM单元
received by a virtual source are removed from the connection. Each ABR control segment, except the last, is terminated by a virtual destination. A virtual destination assumes the behavior of an ABR destination endpoint. Forward RM-cells received by a virtual destination are turned around and not forwarded to the next segment of the connection.
从连接中删除由虚拟源接收的数据。每个ABR控制段（最后一段除外）由虚拟目的地终止。虚拟目的地假定ABR目的地端点的行为。由虚拟目的地接收的转发RM单元将被翻转，而不会转发到连接的下一段。
Discussion: none.
讨论：无。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: An ABR service parameter, XDF controls the decrease in ACR associated with Xrm. It is a power of two in range: [0, 1].
定义：ABR服务参数XDF控制与Xrm相关的ACR的减少。它是范围[0，1]中的二次幂。
Discussion: For ABR traffic, XDM effects the time rate of change of the ACR. This value effects TCP round trip time calculations, which in turn effects TCP throughput.
讨论：对于ABR业务，XDM影响ACR的时间变化率。该值影响TCP往返时间计算，进而影响TCP吞吐量。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: An ABR service parameter, Xrm limits the number of forward RM-cells which may be sent in the absence of received backward PM-cells. The range is 0-255.
定义：ABR服务参数Xrm限制在没有接收到反向PM小区的情况下可以发送的前向RM小区的数量。范围为0-255。
Discussion: For ABR traffic, Xrm effects the time rate of change of the ACR. This value effects TCP round trip time calculations, which in turn effects TCP throughput.
讨论：对于ABR业务，Xrm影响ACR的时间变化率。该值影响TCP往返时间计算，进而影响TCP吞吐量。
Specification: AF-TM4.0
规格：AF-TM4.0
Metric to be defined.
待定义的度量。
Definition: The specific definition for the metric.
定义：度量的特定定义。
Discussion: A brief discussion of the metric, its application and any restrictions on measurement procedures.
讨论：简要讨论度量、其应用和对测量程序的任何限制。
Measurement units: Intrinsic units used to quantify this metric. This includes subsidiary units; e.g., microseconds are acceptable if the intrinsic unit is seconds.
度量单位：用于量化此度量的固有单位。这包括附属单位；e、 例如，如果固有单位为秒，则可接受微秒。
Definition: The amount of time required by the SUT to adjust its transmission rate based on an ABR rate decrease request.
定义：SUT根据ABR速率降低请求调整其传输速率所需的时间量。
Discussion: During the ARDRT, cells transmitted by the SUT may be dropped by the network due to traffic policing. These dropped cells may contain a portion of an IP datagram. This may cause IP and TCP packet loss.
讨论：在ARDRT期间，由于交通管制，SUT传输的小区可能会被网络丢弃。这些丢弃的单元可能包含IP数据报的一部分。这可能会导致IP和TCP数据包丢失。
Measurement Units: seconds
测量单位：秒
Definition: The amount of time required by the SUT to adjust its transmission rate based on an ABR rate increase request.
定义：SUT根据ABR速率增加请求调整其传输速率所需的时间量。
Discussion: During the ARIRT, the SUT will not fully utilize the available bandwidth. This will negatively impact IP and TCP throughput.
讨论：在ARIRT期间，SUT不会充分利用可用带宽。这将对IP和TCP吞吐量产生负面影响。
Measurement Units: seconds
测量单位：秒
Definition: The variation in RM-cell transfer delay (RM-CTD) of RM-cells associated with a given traffic load, orientation and distribution, as well as an integration period. RM-CDV = max (RM-CTD) - min (RM-CTD) where max and min indicate the maximum and minimum over the integration period, respectively.
定义：RM信元的RM信元传输延迟（RM-CTD）的变化与给定的流量负载、方向和分布以及集成周期有关。RM-CDV=最大值（RM-CTD）-最小值（RM-CTD），其中最大值和最小值分别表示积分期间的最大值和最小值。
Discussion: RM-CDV is a component of RM-cell transfer delay, induced by buffering and RM-cell scheduling.
讨论：RM-CDV是RM小区传输延迟的一个组成部分，由缓冲和RM小区调度引起。
RM-CDV effects the time required to notify the source of a change in the condition of the network. This in turn effects TCP round trip time calculations. Large values of RM-CDV will adversely effect TCP throughput and cause SAR timeout.
RM-CDV影响通知来源网络状况变化所需的时间。这反过来会影响TCP往返时间的计算。RM-CDV的较大值将对TCP吞吐量产生不利影响，并导致SAR超时。
Measurement Units: seconds
测量单位：秒
Definition: The ratio of RM-cells with payload errors in a transmission in relation to the total number of RM-cells sent in a transmission associated with a given traffic load, orientation and
定义：传输中存在有效负载错误的RM信元与传输中发送的RM信元总数的比率，与给定的流量负载、方向和时间相关
distribution, as well as an integration period. Note that errors occurring in the RM-cell header will cause RM-cell loss at the ATM layer. Note further that multiple errors in a payload will only be counted as one cell payload error.
分布，以及一个整合期。请注意，RM信元报头中发生的错误将导致ATM层的RM信元丢失。进一步注意，一个有效负载中的多个错误将仅计为一个小区有效负载错误。
RM-CER = RM-Cells with payload errors / Total RM-Cells Transmitted.
RM-CER=有有效负载错误的RM小区/传输的RM小区总数。
Discussion: The measurement is taken over a time interval and is desirable to be measured on an in-service circuit. RM-CER effects the time required to notify the source of a change in the condition of the network. This in turn effects TCP round trip time calculations. Large values of RM-CER will adversely effect TCP throughput and cause SAR timeout.
讨论：测量是在一个时间间隔内进行的，最好在运行中的电路上进行测量。RM-CER影响通知来源网络状况变化所需的时间。这反过来会影响TCP往返时间的计算。RM-CER的较大值将对TCP吞吐量产生不利影响，并导致SAR超时。
Measurement Units: dimensionless.
测量单位：无量纲。
Definition: The ratio of lost RM-cells in a transmission in relation to the total RM-cells sent in a transmission associated with a given traffic load, orientation and distribution, as well as an integration period.
定义：传输中丢失的RM信元与传输中发送的与给定流量负载、方向和分布以及集成周期相关的RM信元总数的比率。
RM-CLR = Lost RM-Cells / Total RM-Cells Transmitted.
RM-CLR=丢失的RM单元/传输的RM单元总数。
Discussion: The objective is to minimize RM-CLR. It is expressed as an order of magnitude, having a range of 10^-1 to 10^-15 and unspecified.
讨论：目标是最小化RM-CLR。它表示为一个数量级，范围为10^-1至10^-15，未指定。
RM-CLR effects the time required to notify the source of a change in the condition of the network. This in turn effects TCP round trip time calculations. Large values of RM-CLR will adversely effect TCP throughput and cause SAR timeout.
RM-CLR影响通知来源网络状况变化所需的时间。这反过来会影响TCP往返时间的计算。RM-CLR的较大值将对TCP吞吐量产生不利影响，并导致SAR超时。
Measurement Units: dimensionless.
测量单位：无量纲。
Definition: The ratio of RM-cells received at an endpoint that were not originally transmitted by the source end in relation to the total number of RM-cells properly transmitted associated with a given traffic load, orientation and distribution, as well as an integration period.
定义：在一个端点接收到的源端最初未传输的RM信元与与与给定流量负载、方向和分布以及集成周期相关的正确传输的RM信元总数的比率。
RM-CMR = Misinserted RM-Cells / Total RM-Cells Transmitted.
RM-CMR=错误插入的RM小区/传输的RM小区总数。
Discussion: The measurement is taken over a time interval and is desirable to be measured on an in-service circuit.
讨论：测量是在一个时间间隔内进行的，最好在运行中的电路上进行测量。
RM-CMR effects the time required to notify the source of a change in the condition of the network. This in turn effects TCP round trip time calculations. Large values of RM-CMR will adversely effect TCP throughput and cause SAR timeout.
RM-CMR影响通知来源网络状况变化所需的时间。这反过来会影响TCP往返时间的计算。RM-CMR的较大值将对TCP吞吐量产生不利影响，并导致SAR超时。
Measurement Units: dimensionless.
测量单位：无量纲。
Definition: The ratio of RM-cells received at an endpoint which contain an invalid CRC in relation to the total number of RM-cells properly transmitted associated with a given traffic load, orientation and distribution, as well as an integration period.
定义：在包含无效CRC的端点处接收的RM信元与与与给定流量负载、方向和分布以及集成周期相关的正确传输的RM信元总数的比率。
Discussion: RM-CRC errors cause ATM RM-cells to be lost.
讨论：RM-CRC错误导致ATM RM信元丢失。
RM-CRC effects the time required to notify the source of a change in the condition of the network. This in turn effects TCP round trip time calculations. Large values of RM-CRC will adversely effect TCP throughput and cause SAR timeout.
RM-CRC影响通知来源网络状况变化所需的时间。这反过来会影响TCP往返时间的计算。RM-CRC的较大值将对TCP吞吐量产生不利影响，并导致SAR超时。
Measurement Units: dimensionless
测量单位：无量纲
Definition: The elapsed time between a RM-cell exit event at the measurement point 1 (e.g., at the source UNI) and the corresponding RM-cell entry event at a measurement point 2 (e.g., the destination UNI) for a particular connection.
定义：特定连接的测量点1（例如，在源UNI）处的RM小区退出事件与测量点2（例如，目标UNI）处的相应RM小区进入事件之间经过的时间。
Discussion: The RM-cell transfer delay between two measurement points is the sum of the total inter-ATM node transmission delay and the total ATM node processing delay. This number is a constant and should not adversely effect performance.
讨论：两个测量点之间的RM信元传输延迟是总ATM节点间传输延迟和总ATM节点处理延迟之和。这个数字是一个常数，不应对性能产生不利影响。
Measurement units: seconds
测量单位：秒
Definition: The ratio of severely errored cell blocks in a transmission in relation to the total cell blocks sent in a transmission associated with a given traffic load, orientation and distribution, as well as an integration period.
定义：传输中严重错误的小区块与传输中发送的总小区块的比率，与给定的流量负载、方向和分布以及集成周期有关。
SECBR = Severely Errored Cell Blocks/Total Transmitted Cell Blocks
SECBR=严重错误的小区块/传输的小区块总数
Discussion: SECBR may cause the SUT to drop cells that may contain a portion of an IP datagram. This may cause IP and TCP packet loss.
讨论：SECBR可能导致SUT丢弃可能包含IP数据报一部分的单元。这可能会导致IP和TCP数据包丢失。
Measurement Units: dimensionless.
测量单位：无量纲。
As this document is solely for providing terminology and describes neither a protocol nor an implementation, there are no security considerations associated with this document.
由于本文档仅用于提供术语，并且既不描述协议也不描述实现，因此本文档没有相关的安全注意事项。
[AF-TM4.0] ATM Forum, Traffic Management Specification Version 4.0, af-tm-0056.00, April 1996.
[AF-TM4.0]ATM论坛，交通管理规范版本4.0，AF-tm-0056.00，1996年4月。
[AF-TM4.1] ATM Forum, Traffic Management Specification Version 4.1, af-tm-0121.000, March 1999.
[AF-TM4.1]ATM论坛，交通管理规范版本4.1，AF-tm-0121.000，1999年3月。
[AF-UNI3.1] ATM Forum, User Network Interface Specification Version 3.1, September 1994.
[AF-UNI3.1]ATM论坛，用户网络接口规范3.1版，1994年9月。
[AF-UNI4.0] ATM Forum, User Network Interface Specification Version 4.0, July 1996.
[AF-UNI4.0]ATM论坛，用户网络接口规范版本4.0，1996年7月。
Jeffrey Dunn Advanced Network Consultants, Inc. 4214 Crest Place Ellicott City, MD 21043 USA
Jeffrey Dunn Advanced Network Consultants，Inc.美国马里兰州埃利科特市克雷斯特广场4214号，邮编：21043
Phone: +1 (410) 750-1700
EMail: Jeffrey.Dunn@worldnet.att.net
Phone: +1 (410) 750-1700
EMail: Jeffrey.Dunn@worldnet.att.net
Cynthia Martin Advanced Network Consultants, Inc. 4214 Crest Place Ellicott City, MD 21043 USA
Cynthia Martin Advanced Network Consultants，Inc.美国马里兰州埃利科特市克雷斯特广场4214号，邮编：21043
Phone: +1 (410) 750-1700
EMail: Cynthia.E.Martin@worldnet.att.net
Phone: +1 (410) 750-1700
EMail: Cynthia.E.Martin@worldnet.att.net
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确认
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