Network Working Group J. Dunn
Request for Comments: 2761 C. Martin
Category: Informational ANC, Inc.
February 2000
Network Working Group J. Dunn
Request for Comments: 2761 C. Martin
Category: Informational ANC, Inc.
February 2000
Terminology for ATM Benchmarking
ATM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 (2000). All Rights Reserved.
版权所有（C）互联网协会（2000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. The terms defined in this memo will be used in addition to terms defined in RFCs 1242, 2285, and 2544. 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基于异步传输模式（ATM）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和2544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。
Introduction
介绍
This document provides terminology for benchmarking ATM based switching devices. It extends terminology already defined for benchmarking network interconnect devices in RFCs 1242, 2285, and 2544. 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 cell relay and signaling.
本文档提供了基于ATM的交换设备基准测试术语。它扩展了RFCs 1242、2285和2544中为基准网络互连设备定义的术语。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信元中继和信令。
This memo contains two major sections: Background and Definitions. Within the definitions section is a formal definitions subsection, provided as a courtesy to the reader, and a measurement definitions sub-section, that contains performance metrics with inherent units. The divisions of the measurement sub-section follow the BISDN model.
本备忘录包含两个主要部分：背景和定义。在定义部分中，有一个正式的定义小节，作为对读者的礼貌，还有一个度量定义小节，其中包含具有固有单位的性能度量。测量子部分的划分遵循BISDN模型。
The BISDN model comprises four layers and two planes. This document addresses the interactions between these layers and how they effect IP and TCP throughput. A schematic of the B-ISDN model follows:
BISDN模型包括四层和两个平面。本文档介绍这些层之间的交互以及它们如何影响IP和TCP吞吐量。B-ISDN模型的示意图如下所示：
---------|--------------------------|-------------------------------
| User Plane | Control Plane
---------|--------------------------|--------------------------------
Services | IP | ILMI | UNI, PNNI
---------|--------------------------|----------|---------------------
AAL | AAL1, AAL2, AAL3/4, AAL5 | AAL5 | SAAL
---------|--------------------------|----------|---------------------
ATM | Cell Relay | OAM, RM
---------|--------------------------|--------------------------------
| Convergence |
Physical |--------------------------|--------------------------------
| Media |
---------|--------------------------|--------------------------------
---------|--------------------------|-------------------------------
| User Plane | Control Plane
---------|--------------------------|--------------------------------
Services | IP | ILMI | UNI, PNNI
---------|--------------------------|----------|---------------------
AAL | AAL1, AAL2, AAL3/4, AAL5 | AAL5 | SAAL
---------|--------------------------|----------|---------------------
ATM | Cell Relay | OAM, RM
---------|--------------------------|--------------------------------
| Convergence |
Physical |--------------------------|--------------------------------
| Media |
---------|--------------------------|--------------------------------
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 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). This document covers only CBR, VBR and UBR traffic types. ABR will be handled in a separate document. 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.
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，并且能够执行信令呼叫设置（通过UNI或PNNI信令）。本文档仅涵盖CBR、VBR和UBR流量类型。ABR将在单独的文件中处理。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。
Existing Definitions
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. For the sake of clarity and continuity, this RFC adopts the template for definitions set out in Section 2 of RFC 1242. Definitions are indexed and grouped together in sections for ease of
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”包含许多与流量分布和数据报到达间隔相关的术语。为了清晰和连续性，本RFC采用RFC 1242第2节规定的定义模板。定义被编入索引，并在各节中分组，以便于理解
reference. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" go in this document are to be interpreted as described in RFC 2119.
参考本文件中的关键词“必须”、“不得”、“要求”、“应”、“不得”、“应”、“不应”、“建议”、“可”和“可选”应按照RFC 2119中的说明进行解释。
Definitions
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. These discussions pertain solely to the impact of a particular ATM parameter on IP or TCP; therefore, definitions which contain no configurable components or whose components will have the discussion: None.
讨论：简要讨论该术语、其应用和对测量程序的任何限制。这些讨论仅涉及特定ATM参数对IP或TCP的影响；因此，不包含可配置组件或其组件将引起讨论的定义为：无。
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。
Definition: The layer in the B-ISDN reference model (see B-ISDN) which adapts higher layer PDUs into the ATM layer.
定义：B-ISDN参考模型（参见B-ISDN）中的层，它将更高层PDU适配到ATM层。
Discussion: There are four types of adaptation layers: AAL 1: used
for circuit qemulation, voice over ATM AAL2: used for sub-rated voice
over ATM AAL3/4: used for data over noisy ATM lines AAL5: used for
data over ATM, most widely used AAL type
Discussion: There are four types of adaptation layers: AAL 1: used
for circuit qemulation, voice over ATM AAL2: used for sub-rated voice
over ATM AAL3/4: used for data over noisy ATM lines AAL5: used for
data over ATM, most widely used AAL type
These AAL types are not measurements, but it is possible to measure the time required for Segmentation and Reassembly (SAR).
这些AAL类型不是测量值，但可以测量分段和重新组装（SAR）所需的时间。
Specification: I.363
规格：I.363
Definition: AAL5 adapts multi-cell higher layer PDUs into ATM with minimal error checking and no error detection. The AAL5 CPCS (Common Paer Convergence Sub-layer) PDU is defined as follows:
定义：AAL5将多小区高层PDU适配到ATM中，具有最小的错误检查和无错误检测。AAL5 CPCS（公共Paer会聚子层）PDU定义如下：
|---------------------------|---------------------------|--------------|
| Higher Layer PDU | Padding (If needed) | Trailer |
|---------------------------|---------------------------|--------------|
|---------------------------|---------------------------|--------------|
| Higher Layer PDU | Padding (If needed) | Trailer |
|---------------------------|---------------------------|--------------|
Where the padding is used to ensure that the trailer occupies the final 8 octets of the last cell.
填充用于确保拖车占用最后一个单元格的最后8个八位字节。
The trailer is defined as follows:
拖车的定义如下：
|--------------|--------------|--------------|--------------|
| CPCS-UU | CPI | Length | CRC-32 |
|--------------|--------------|--------------|--------------|
|--------------|--------------|--------------|--------------|
| CPCS-UU | CPI | Length | CRC-32 |
|--------------|--------------|--------------|--------------|
where:
哪里：
CPCS-UU is the 1 octet Common Part Convergence Sub-layer User to User Indication and may be used to communicate between two AAL5 entities.
CPCS-UU是1个八位组公共部分汇聚子层用户对用户指示，可用于两个AAL5实体之间的通信。
CPI is the 1 octet Common Part Indicator and must be set to 0.
CPI是1个八位字节的公共部分指示器，必须设置为0。
Length is the 2 octet length of the higher layer PDU.
长度是较高层PDU的2个八位组长度。
CRC-32 is a 32 bit (4 octet) cyclic redundancy check over the entire PDU.
CRC-32是整个PDU上的32位（4个八位组）循环冗余校验。
Discussion: AAL5 is the adaptation layer for UNI signaling, ILMI, PNNI signaling, and for IP PDUs. It is the most widely used AAL type to date. AAL5 requires two distinct processes. The first is the encapsulation, on the transmit side, and de-encapsulation, on the receive side, of the higher layer PDU into the AAL5 CPCS PDU which requires the computation of the length and the CRC-32. The time required for this process depends on whether the CRC-32 computation is done on the interface (on-board) or in machine central memory (in core). On-board computation should produce only a small, constant delay; however, in core computation will produce variable delay, which will negatively effect TCP RTT computations. The second process is segmentation and re-assembly (SAR) which is defined below (see
讨论：AAL5是UNI信令、ILMI、PNNI信令和IP PDU的适配层。它是迄今为止使用最广泛的AAL类型。AAL5需要两个不同的过程。第一个是在传输侧将上层PDU封装到AAL5 CPCS PDU中，在接收侧将其解封装到AAL5 CPCS PDU中，这需要计算长度和CRC-32。此过程所需的时间取决于CRC-32计算是在接口（板载）还是在机器中央存储器（核心）中完成。车载计算只应产生一个小的、恒定的延迟；然而，内核计算将产生可变延迟，这将对TCP RTT计算产生负面影响。第二个过程是分段和重新组装（SAR），定义如下（参见
SAR).
特区）。
Specification: I.363.5
规格：I.363.5
Definition: A transfer mode in which the information is organized into 53 octet PDUs called cells. It is asynchronous in the sense that the recurrence of cells containing information from an individual user is not necessarily periodic.
定义：一种传输模式，其中信息被组织成53个八位组PDU，称为单元。它是异步的，因为包含单个用户信息的单元格的重复不一定是周期性的。
Discussion: ATM is based on the ISDN model; however, unlike ISDN, ATM uses fixed length (53 octet) cells. Because of the fixed length of ATM PDUs, higher layer PDUs must be adapted into ATM using one of the four ATM adaptation layers (see AAL).
讨论：ATM基于ISDN模型；然而，与ISDN不同，ATM使用固定长度（53个八位组）信元。由于ATM PDU的长度是固定的，因此必须使用四个ATM适配层之一将更高层的PDU适配到ATM中（参见AAL）。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A virtual path link (VPL) or a virtual channel link (VCL).
定义：虚拟路径链路（VPL）或虚拟通道链路（VCL）。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A virtual channel connection (VCC) or a virtual path connection (VPC).
定义：虚拟通道连接（VCC）或虚拟路径连接（VPC）。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A generic list of traffic parameters, which specify the intrinsic traffic characteristics of a requested ATM connection (see GCRA), which must include PCR and QoS and may include BT, SCR and best effort (UBR) indicator.
定义：流量参数的通用列表，用于指定请求的ATM连接的固有流量特征（参见GCRA），必须包括PCR和QoS，并可能包括BT、SCR和最佳努力（UBR）指示器。
Discussion: The effects of each traffic parameter will be discussed individually.
讨论：将单独讨论每个交通参数的影响。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: An association established by the ATM Layer to support communication between two or more ATM service users (i.e., between two or more next higher entities or between two or more ATM-entities). The communications over an ATM Layer connection may be either bi-directional or unidirectional. The same Virtual Channel Identifier (VCI) is issued for both directions of a connection at an interface.
定义：由ATM层建立的关联，用于支持两个或多个ATM服务用户之间的通信（即，两个或多个下一级实体之间或两个或多个ATM实体之间）。ATM层连接上的通信可以是双向的，也可以是单向的。为接口处连接的两个方向发出相同的虚拟通道标识符（VCI）。
Discussion: Because ATM is connection oriented, certain features of IP (i.e. those which require multicast) are not available.
讨论：由于ATM是面向连接的，IP的某些功能（即需要多播的功能）不可用。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A layered service model that specifies the mapping of higher layer protocols onto ATM and its underlying physical layer. The model is composed of four layers: Physical, ATM, AAL and Service.
定义：一种分层服务模型，用于指定更高层协议到ATM及其底层物理层的映射。该模型由四层组成：物理层、ATM层、AAL层和业务层。
Discussion: See discussion above.
讨论：见上面的讨论。
Specification: I.321
规格：I.321
Definition: A traffic parameter, which, along with the Sustainable Cell Rate (SCR), specifies the maximum number of cells which will be accepted at the Peak Cell Rate (PCR) on an ATM connection.
定义：一个流量参数，与可持续信元速率（SCR）一起指定ATM连接上在峰值信元速率（PCR）下可接受的最大信元数。
Discussion: BT applies to ATM connections supporting VBR services and is the limit parameter of the GCRA. BT will effect TCP and IP PDU loss in that cells presented to an interface which violate the BT may be dropped, which will cause AAL5 PDU corruption. BT will also effect TCP RTT calculation. BT=(MBS-1)*(1/SCR 1/PCR) (see MBS, PCR, SCR).
讨论：BT适用于支持VBR服务的ATM连接，是GCRA的限制参数。BT将影响TCP和IP PDU的丢失，因为提供给接口的违反BT的单元可能会被丢弃，这将导致AAL5 PDU损坏。BT还将影响TCP RTT计算。BT=（MBS-1）*（1/SCR 1/PCR）（见MBS，PCR，SCR）。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: A call is an association between two or more users or between a user and a network entity that is established by the use of network capabilities. This association may have zero or more connections.
定义：呼叫是两个或多个用户之间或用户与网络实体之间通过使用网络功能建立的关联。此关联可能有零个或多个连接。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A unit of transmission in ATM. A fixed-size frame consisting of a 5-octet header and a 48-octet payload.
定义：ATM中的一种传输单位。一种固定大小的帧，由5个八位字节的头和48个八位字节的有效载荷组成。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A transport requiring call setups - see CALL definition.
定义：需要呼叫设置的传输-请参阅呼叫定义。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: ATM layer functions may alter the traffic characteristics of ATM connections by introducing Cell Delay Variation. When cells from two or more ATM connections are multiplexed, cells of a given ATM connection may be delayed while cells of another ATM connection are being inserted at the output of the multiplexer. Similarly, some cells may be delayed while physical layer overhead or OAM cells are inserted. Consequently, some randomness may affect the inter-arrival time between consecutive cells of a connection as monitored at the UNI. The upper bound on the "clumping" measure is the CDVT.
定义：ATM层功能可能通过引入信元延迟变化来改变ATM连接的流量特性。当来自两个或多个ATM连接的信元被多路复用时，当另一个ATM连接的信元被插入多路复用器的输出端时，给定ATM连接的信元可能被延迟。类似地，当插入物理层开销或OAM小区时，一些小区可能被延迟。因此，一些随机性可能影响在UNI处监视的连接的连续小区之间的到达时间。“聚集”度量的上限是CDVT。
Discussion: CDVT effects TCP round trip time calculations. Large values of CDVT will adversely effect TCP throughput and cause SAR timeout. See discussion under SAR.
讨论：CDVT影响TCP往返时间计算。CDVT的大值将对TCP吞吐量产生不利影响，并导致SAR超时。见SAR下的讨论。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: ATM Layer protocol control information.
定义：ATM层协议控制信息。
Discussion: The ATM cell header is a 5-byte header that contains the following fields: Generic Flow Control (GFC) 4 bits Virtual Path Identifier (VPI) 8 bits Virtual Channel Identifier (VCI) 16 bits Payload Type (PT) 3 bits Cell Loss Priority (CLP) 1 bit Header Error Check (HEC) 8 bit CRC computed over the previous four octets
讨论：ATM信元报头是一个5字节的报头，包含以下字段：通用流量控制（GFC）4位虚拟路径标识符（VPI）8位虚拟通道标识符（VCI）16位有效负载类型（PT）3位信元丢失优先级（CLP）1位报头错误检查（HEC）在前四个八位字节上计算的8位CRC
Each field is discussed in this document.
本文档将讨论每个字段。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: This bit in the ATM cell header indicates two levels of priority for ATM cells. CLP=0 cells are higher priority than CLP=1 cells. CLP=1 cells may be discarded during periods of congestion to preserve the CLR of CLP=0 cells.
定义：ATM信元报头中的该位表示ATM信元的两级优先级。CLP=0单元格的优先级高于CLP=1单元格。CLP=1小区可能在拥塞期间被丢弃，以保留CLP=0小区的CLR。
Discussion: The CLP bit is used to determine GCRA contract compliance. Specifically, two traffic contracts may apply to a single connection: CLP=0, meaning only cells with CLP=0, and CLP=0+1, meaning cells with CLP=0 or CLP=1.
讨论：CLP bit用于确定GCRA合同合规性。具体地说，两个流量契约可应用于单个连接：CLP=0，表示仅具有CLP=0的小区；CLP=0+1，表示具有CLP=0或CLP=1的小区。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: An ATM connection consists of concatenation of ATM Layer links in order to provide an end-to-end information transfer capability to access points.
定义：ATM连接由ATM层链路的串联组成，以便向接入点提供端到端的信息传输能力。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: Connection Admission Control is defined as the set of actions taken by the network during the call set-up phase (or during call re-negotiation phase) in order to determine whether a connection request can be accepted or should be rejected (or whether a request for re-allocation can be accommodated).
定义：连接允许控制定义为网络在呼叫建立阶段（或呼叫重新协商阶段）采取的一组操作，以确定连接请求是否可以接受或应该拒绝（或重新分配请求是否可以接受）。
Discussion: CAC is based on the ATM traffic descriptor (see ATM traffic descriptor) associated with the call as well as the presented and existing load. It may also be based on administrative policies such as calling party number required or access limitations. The effect on performance of these policies is beyond the scope of this document and will be handled in the BMWG document: Benchmarking Terminology for Firewall Performance.
讨论：CAC基于与呼叫相关联的ATM流量描述符（参见ATM流量描述符）以及当前和现有负载。它也可能基于管理策略，如所需呼叫方号码或访问限制。这些策略对性能的影响超出了本文档的范围，将在BMWG文档：防火墙性能基准术语中处理。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: An ATM service category which supports a constant and guaranteed rate to transport services such as video or voice as well as circuit emulation which requires rigorous timing control and performance parameters. CBR requires the specification of PCR and QoS (see PCR and QoS).
定义：ATM服务类别，支持视频或语音等恒定且有保证的传输速率，以及需要严格定时控制和性能参数的电路仿真。CBR需要PCR和QoS规范（参见PCR和QoS）。
Discussion: Because CBR provides minimal cell delay variation (see CDV), it should improve TCP throughput by stabilizing the RTT calculation. Further, as CBR generally provides a high priority service, meaning that cells with a CBR traffic contract usually take priority over other cells during congestion, TCP segment and IP packet loss should be minimized. The cost associated with using CBR is the loss of statistical multiplexing. Since CBR guarantees both throughput and CDV control, the connections must be subscribed at PCR. This is extremely wasteful as most protocols, e.g., TCP, only utilize full bandwidth on one half of a bi-directional connection.
讨论：由于CBR提供最小的小区延迟变化（参见CDV），因此它应该通过稳定RTT计算来提高TCP吞吐量。此外，由于CBR通常提供高优先级服务，这意味着在拥塞期间，具有CBR流量契约的小区通常优先于其他小区，因此应将TCP段和IP数据包丢失降至最低。与使用CBR相关的成本是统计复用的损失。由于CBR保证吞吐量和CDV控制，因此必须在PCR时订阅连接。这是非常浪费的，因为大多数协议（例如TCP）只在双向连接的一半上使用全部带宽。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A mathematical algorithm that computes a numerical value based on the bits in a block of data. This number is transmitted with the data, the receiver uses this information and the same algorithm to insure the accurate delivery of data by comparing the results of algorithm, and the number received. If a mismatch occurs, an error in transmission is presumed.
定义：根据数据块中的位计算数值的数学算法。此数字与数据一起传输，接收器使用此信息和相同的算法，通过比较算法结果和接收到的数字，确保数据的准确传输。如果出现不匹配，则假定传输中存在错误。
Discussion: CRC is not a measurement, but it is possible to measure the amount of time to perform a CRC on a string of bits. This measurement will not be addressed in this document. See discussion under AAL5.
讨论：CRC不是一种测量，但可以测量对一串位执行CRC的时间量。本文件将不讨论该测量。参见AAL5下的讨论。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A system where an ATM connection is terminated or initiated. An originating end system initiates the ATM connection, and terminating end system terminates the ATM connection. OAM cells may be generated and received.
定义：终止或启动ATM连接的系统。发起端系统启动ATM连接，终止端系统终止ATM连接。可以生成和接收OAM小区。
Discussion: An ES can be the user side of a UNI signaling interface.
讨论：ES可以是UNI信令接口的用户端。
Specification: AF-TEST-0022
规格：AF-TEST-0022
Definition: EFCI is an indication in the PTI field of the ATM cell header. A network element in an impending-congested state or a congested state may set EFCI so that this indication may be examined by the destination end-system. For example, the end-system may use this indication to implement a protocol that adaptively lowers the cell rate of the connection during congestion or impending congestion. A network element that is not in a congestion state or an impending congestion state will not modify the value of this indication. Impending congestion is the state when network equipment is operating around its engineered capacity level.
定义：EFCI是ATM信元报头的PTI字段中的指示。处于即将发生的拥塞状态或拥塞状态的网元可以设置EFCI，以便目的地终端系统可以检查该指示。例如，终端系统可以使用该指示来实现协议，该协议在拥塞或即将发生的拥塞期间自适应地降低连接的小区速率。未处于拥塞状态或即将发生的拥塞状态的网元不会修改此指示的值。即将发生的拥塞是指网络设备在其设计容量水平附近运行时的状态。
Discussion: EFCI may be used to prevent congestion by alerting a positive acknowledgement protocol and causing action to be taken. In the case of TCP, when EFCI cells are received the driver software could alert the TCP software of impending congestion. The TCP receiver would then acknowledge the current segment and set the window size to some very small number.
讨论：EFCI可通过向肯定确认协议发出警报并导致采取措施来防止拥塞。对于TCP，当接收到EFCI单元时，驱动程序软件可以向TCP软件发出即将发生拥塞的警报。TCP接收器随后将确认当前段，并将窗口大小设置为某个非常小的数字。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: The GCRA is used to define conformance with respect to the traffic contract of the connection. For each cell arrival, the GCRA determines whether the cell conforms to the traffic contract. The UPC function may implement the GCRA, or one or more equivalent algorithms to enforce conformance. The GCRA is defined with two parameters: the Increment (I) and the Limit (L).
定义：GCRA用于定义连接的流量合同的一致性。对于每个小区的到达，GCRA确定该小区是否符合流量合同。UPC功能可实现GCRA或一个或多个等效算法以强制一致性。GCRA由两个参数定义：增量（I）和极限（L）。
Discussion: The GCRA increment and limit parameters are mapped to CBR and VBR in the following fashion. For CBR, I=1/PCR and L=CDVT (CDV tolerance). For VBR, there are two GCRA algorithms running (dual leaky bucket). The first functions in the same fashion .bp as CBR, I=1/PCR and L=CDVT. The second, which polices cells which are in conformance with the first GCRA uses I=1/SCR and L=BT (see BT, CDV,
讨论：GCRA增量和极限参数以以下方式映射到CBR和VBR。对于CBR，I=1/PCR和L=CDVT（CDV耐受性）。对于VBR，有两种GCRA算法正在运行（双漏桶）。第一个功能与CBR相同。bp为CBR，I=1/PCR，L=CDVT。第二个是对符合第一个GCRA的电池进行管理，使用I=1/SCR和L=BT（见BT，CDV，
MBS, PCR and SCR).
MBS、PCR和SCR）。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: GFC is a field in the ATM header, which can be used to provide local functions (e.g., flow control). It has local significance only and the value encoded in the field is not carried end-to-end.
定义：GFC是ATM报头中的一个字段，可用于提供本地功能（如流量控制）。它仅具有局部意义，字段中编码的值不进行端到端的传输。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: The GFR service provides the user with a Minimum Cell Rate (MCR) guarantee under the assumption of a given maximum frame size (MFS) and a given Maximum Burst Size (MBS). The MFS and MBS are both expressed in units of cells. GFR only applies to virtual channel connections (VCCs).
定义：GFR服务在给定最大帧大小（MFS）和给定最大突发大小（MBS）的假设下为用户提供最小小区速率（MCR）保证。MFS和MBS均以细胞单位表示。GFR仅适用于虚拟通道连接（VCC）。
Discussion: GFR is intended for users who are either not able to specify the range of traffic parameters needed to request most ATM services, or are not equipped to comply with the (source) behavior rules required by existing ATM services. Specifically, GFR provides the user with the following minimum service guarantee: When the network is congested, all frames whose length is less than MFS and presented to the ATM interface in bursts less than MBS and at a rate less than PCR will be handled with minimum frame loss. When the network is not congested, the user can burst at higher rates.
讨论：GFR适用于不能指定请求大多数ATM服务所需的流量参数范围，或不符合现有ATM服务所需的（源）行为规则的用户。具体而言，GFR为用户提供了以下最低服务保证：当网络拥塞时，长度小于MFS且以小于MBS的突发速率以小于PCR的速率呈现给ATM接口的所有帧将以最小的帧丢失率进行处理。当网络不拥挤时，用户可以以更高的速率突发。
The effect of GFR on performance is somewhat problematic as the policing algorithm associated with GFR depends on the network load; however, under congested condition and assuming a user who is following the GFR service agreement, it should improve performance.
GFR对性能的影响有些问题，因为与GFR相关联的策略算法取决于网络负载；但是，在拥挤条件下，假设用户遵守GFR服务协议，则应提高性能。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: A check character calculated using an 8 bit CRC computed over the first 4 octets of the ATM cell header. This allows for single bit error correction or multiple bit error detection.
定义：使用在ATM信元头的前4个八位字节上计算的8位CRC计算的校验字符。这允许进行单位错误校正或多位错误检测。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A management protocol which uses SNMPv1 carried on AAL5 to provide ATM network devices with status and configuration information concerning VPCs, VCCs, registered ATM addresses and the capabilities of ATM interfaces.
定义：一种管理协议，使用AAL5上携带的SNMPv1向ATM网络设备提供有关VPC、VCC、注册ATM地址和ATM接口能力的状态和配置信息。
Discussion: ILMI is a conditionally required portion of UNI3.1; however, ILMI 4.0 has been issued as a separate specification. This document will refer to ILMI 4.0.
讨论：ILMI是UNI3.1中有条件要求的部分；但是，ILMI 4.0已作为单独的规范发布。本文件将参考ILMI 4.0。
Specification: AF-ILMI4.0
规格：AF-ILMI4.0
Definition: A system that provides forwarding functions or relaying functions or both for a specific ATM connection. OAM cells may be generated and received.
定义：为特定ATM连接提供转发功能或中继功能或两者兼有的系统。可以生成和接收OAM小区。
Discussion: An IS can be either the user or network side of a UNI signaling interface, or the network side of a PNNI signaling interface.
讨论：IS可以是UNI信令接口的用户侧或网络侧，也可以是PNNI信令接口的网络侧。
Specification: AF-TEST-0022
规格：AF-TEST-0022
Definition: Leaky Bucket is the term used as an analogous description of the algorithm used for conformance checking of cell flows from a user or network. See GCRA and UPC. The "leaking hole in the bucket" applies to the sustained rate at which cells can be accommodated, while the "bucket depth" applies to the tolerance to cell bursting over a given time period.
定义：漏桶是用于对来自用户或网络的单元流进行一致性检查的算法的类似描述。见GCRA和UPC。“桶中的泄漏孔”适用于可容纳电池的持续速率，“桶深度”适用于给定时间段内电池破裂的公差。
Discussion: There are two types of LB algorithms - single and dual. Single LB is used in CBR; dual LB is used in VBR (see CBR and VBR).
讨论：有两种类型的LB算法-单和双。CBR采用单LB；双LB用于VBR（参见CBR和VBR）。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: In the signaling message, the Burst Tolerance (BT) is conveyed through the MBS that is coded as a number of cells. The BT together with the SCR and the PCR determine the MBS that may be transmitted at the peak rate and still is in conformance with the GCRA.
定义：在信令消息中，突发容忍度（BT）通过编码为多个小区的MBS传输。BT与SCR和PCR一起确定可能以峰值速率传输且仍符合GCRA的MBS。
Discussion: See the discussion under BT.
讨论：参见BT下的讨论。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: The MFS is the maximum length of a frame, expressed in units of cells, which in interface implementing GFR will accept during congested conditions (see GFR).
定义：MFS是帧的最大长度，以单元为单位表示，在拥挤条件下，实现GFR的接口将接受该长度（参见GFR）。
Discussion: During congestion, frames whose size is in excess of the MFS may be dropped or tagged. Assuming that the user is adhering to the MFS limit, this behavior should improve performance by improving congestion.
讨论：在拥塞期间，可能会丢弃或标记大小超过MFS的帧。假设用户遵守MFS限制，此行为应通过改善拥塞来提高性能。
Specification: AF-TM4.1
规格：AF-TM4.1
Definition: A group of network management functions that provide network fault indication, performance information, and data and diagnosis functions.
定义：一组网络管理功能，提供网络故障指示、性能信息、数据和诊断功能。
Discussion: There are four types of ATM OAM flows: segment or end-to-end VP termination management (i.e. F4 segment, F4 E2E) and segment or end-to-end VC termination management (i.e. F5 segment, F5 E2E). These OAM cells can be used to identify fault management, connection verification, and loop back measurements.
讨论：ATM OAM流有四种类型：段或端到端VP终止管理（即F4段、F4 E2E）和段或端到端VC终止管理（即F5段、F5 E2E）。这些OAM单元可用于识别故障管理、连接验证和环回测量。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: Payload Type Indicator is the Payload Type field value distinguishing the various management cells and user cells as well as conveying explicit forward congestion indication (see EFCI). Example: Resource Management cell is indicated as PTI=110, End-to-end OAM F5 Flow cell is indicated as PTI=101.
定义：有效负载类型指示器是有效负载类型字段值，用于区分各种管理单元和用户单元，并传达明确的前向拥塞指示（请参阅EFCI）。示例：资源管理单元指示为PTI=110，端到端OAM F5流单元指示为PTI=101。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A traffic parameter, which specifies the upper bound on the rate at which ATM cells can be submitted to an ATM connection. This parameter is used by the GCRA.
定义：一个流量参数，指定ATM信元可以提交到ATM连接的速率上限。GCRA使用此参数。
Discussion: PCR directly limits the maximum data rate on an ATM connection. If a user violates the PCR, cells may be dropped resulting in Cell Loss. This in turn will negatively impact AAL5 PDUs, which may be carrying IP datagrams. See the discussion under SAR.
讨论：PCR直接限制ATM连接上的最大数据速率。如果用户违反PCR，细胞可能会掉落，导致细胞丢失。这反过来会对AAL5 PDU产生负面影响，因为AAL5 PDU可能承载IP数据报。参见SAR下的讨论。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: This is a link with static route(s) defined in advance, usually by manual setup.
定义：这是一个预先定义静态路由的链接，通常通过手动设置。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A Virtual Channel Connection (VCC) is an ATM connection where switching is performed on the VPI/VCI fields of each cell. A permanent VCC is one that is provisioned through some network management function and left up indefinitely.
定义：虚拟通道连接（VCC）是一种ATM连接，其中在每个信元的VPI/VCI字段上执行交换。永久VCC是通过某些网络管理功能提供并无限期保留的VCC。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A Virtual Path Connection (VPC) is an ATM connection where switching is performed on the VPI field only of each cell. A permanent VPC is one that is provisioned through some network management function and left up indefinitely.
定义：虚拟路径连接（VPC）是一种ATM连接，其中交换仅在每个信元的VPI字段上执行。永久性专有网络是通过某些网络管理功能提供并无限期保留的专有网络。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A routing information protocol that enables extremely, scalable, full function, dynamic multi-vendor ATM switches to be integrated in the same network.
定义：一种路由信息协议，可在同一网络中集成高度可扩展、全功能、动态的多供应商ATM交换机。
Discussion: PNNI consists of signaling and routing between ATM network devices. PNNI signaling is based on UNI 4.0 signaling between two network side interfaces, while PNNI routing provides a mechanism to route ATM cells between two separate, autonomous ATM networks.
讨论：PNNI包括ATM网络设备之间的信令和路由。PNNI信令基于两个网络侧接口之间的UNI 4.0信令，而PNNI路由提供了一种在两个独立、自治的ATM网络之间路由ATM信元的机制。
Specification: AF-PNNI1.0
规格：AF-PNNI1.0
Definition: A PDU is a message of a given protocol comprising payload and protocol-specific control information, typically contained in a header. PDUs pass over the protocol interfaces that exist between the layers of protocols (per OSI model).
定义：PDU是给定协议的消息，包括有效载荷和特定于协议的控制信息，通常包含在报头中。PDU通过存在于协议层之间的协议接口（根据OSI模型）。
Discussion: In ATM networks, a PDU can refer to an ATM cell, multiple ATM cells, an AAL segment, an IP datagram and others.
讨论：在ATM网络中，PDU可以指一个ATM信元、多个ATM信元、一个AAL段、一个IP数据报等。
Specification: Common Usage
规格：常用
Definition: The process used by the AAL in the B-ISDN reference model (see B-ISDN) which fragments higher layer PDUs into ATM cells.
定义：AAL在B-ISDN参考模型（见B-ISDN）中使用的过程，该过程将更高层PDU分割成ATM信元。
Discussion: SAR is not a measurement, but the speed in which SAR can be completed on a bit stream can be measured. Although this measurement is not included in this document, it should be noted that the manner in which SAR is performed will greatly effect performance. SAR can be performed either on the interface card (on board) or in machine central memory (in core). On-board computation should
讨论：SAR不是一种测量，但可以测量在比特流上完成SAR的速度。尽管本文件中未包括该测量，但应注意，SAR的执行方式将极大地影响性能。SAR可以在接口卡（车载）或机器中央存储器（核心）上执行。船上计算应
produce only a small, constant delay; however, in core computation will produce variable delay, which will negatively effect TCP RTT computations. This situation is further complicated by the location of the CRC-32 calculation. Given an in core CRC-32 calculation, bus contention may cause on board SAR to be slower than in core SAR. Clearly, on board CRC-32 calculation and SAR will produce the most favorable performance results.
只产生一个小的、持续的延迟；然而，内核计算将产生可变延迟，这将对TCP RTT计算产生负面影响。由于CRC-32计算的位置，这种情况更加复杂。给定核心内CRC-32计算，总线争用可能导致车载SAR比核心SAR慢。显然，机载CRC-32计算和SAR将产生最有利的性能结果。
SAR performance will also be effected by ATM layer impairments. Cell error (CE), cell loss(CL), cell mis-insertion (CM) and cell delay variation (CDV) will all negatively effect SAR. CE will cause an AAL5 PDU to fail the CRC-32 check and be discarded, thus discarding the packet which the PDU contained. CL and CM will both cause an AAL5 PDU to fail the length check and be discarded. CL can have other effects depending on whether the cell which was lost is the final cell (PTI=1) of the AAL5 PDU. The following discussion enumerates the possibilities.
SAR性能也会受到ATM层损伤的影响。信元错误（CE）、信元丢失（CL）、信元错误插入（CM）和信元延迟变化（CDV）都会对SAR产生负面影响。CE将导致AAL5 PDU无法通过CRC-32检查并被丢弃，从而丢弃PDU包含的数据包。CL和CM都会导致AAL5 PDU无法通过长度检查并被丢弃。根据丢失的单元是否为AAL5 PDU的最终单元（PTI=1），CL可能具有其他影响。下面的讨论列举了各种可能性。
1. PTI=0 cell is lost. In this case, re-assembly registers a length discrepancy and discards the PDU.
1. PTI=0单元丢失。在这种情况下，重新组装会注册长度差异并丢弃PDU。
2. PTI=1 cell is lost.
2. PTI=1个单元丢失。
2. A. The AAL5 re-assembly timer expires before the first cell, PTI=0, of the next AAL5 PDU arrives. The AAL5 PDU with the missing PTI=1 cell is discarded due to re-assembly timeout and one packet is lost.
2. A.在下一个AAL5 PDU的第一个单元PTI=0到达之前，AAL5重新组装计时器过期。由于重新组装超时，丢失PTI=1单元的AAL5 PDU被丢弃，一个数据包丢失。
2. B. The first cell of the next AAL5 PDU arrives before the re-assembly timer expires. The AAL5 with the missing PTI=1 cell is prepended to the next AAL5 PDU in the SAR engine. This yields two possibilities:
2. B.下一个AAL5 PDU的第一个单元在重新组装计时器到期之前到达。缺少PTI=1单元的AAL5将前置到SAR引擎中的下一个AAL5 PDU。这就产生了两种可能性：
2. B. i. The AAL5 re-assembly timer expires before the last cell, PTI=1, of the next AAL5 PDU arrives. The AAL5 PDU with the missing PTI=1 cell and the next AAL5 PDU are discarded due to re-assembly timeout and two packets are lost.
2. B.i。AAL5重新组装计时器在下一个AAL5 PDU的最后一个单元PTI=1到达之前过期。由于重新组装超时，丢失PTI=1单元的AAL5 PDU和下一个AAL5 PDU被丢弃，两个数据包丢失。
2. B. ii. The last cell of the next AAL5 PDU arrives before the re-assembly timer expires. In this case, AAL5 registers a length discrepancy and discards the PDU; therefore, the AAL5 PDU with the missing PTI=1 cell and the next AAL5 PDU are discarded due to their concatenation and two packets are lost.
2. B.二。下一个AAL5 PDU的最后一个单元在重新组装计时器到期之前到达。在这种情况下，AAL5注册长度差异并丢弃PDU；因此，缺少PTI=1单元的AAL5 PDU和下一个AAL5 PDU由于其串联而被丢弃，并且两个数据包丢失。
2. C. Coupled with re-assembly, there exists some mechanism for identifying the start of a higher layer PDU, e.g., IP, and the cells associated with the first incomplete AAL5 PDU are discarded, resulting in the loss of one packet.
2. C.与重新组装相结合，存在用于识别更高层PDU（例如IP）的开始的一些机制，并且与第一个不完整的AAL5 PDU相关联的单元被丢弃，导致丢失一个分组。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: The SCR is an upper bound on the conforming average rate of an ATM connection over time scales which are long relative to those for which the PCR is defined. Enforcement of this bound by the UPC could allow the network to allocate sufficient resources, but less than those based on the PCR, and still ensure that the performance objectives (e.g., for Cell Loss Ratio) can be achieved.
定义：SCR是ATM连接在时间尺度上的一致性平均速率的上限，该时间尺度相对于定义PCR的时间尺度较长。UPC对这一约束的实施可以允许网络分配足够的资源，但比基于PCR的资源要少，并且仍然可以确保实现性能目标（例如，小区丢失率）。
Discussion: SCR limits the average data rate on an ATM connection. If a user violates the SCR, cells may be dropped resulting in Cell Loss. This in turn will negatively impact AAL5 PDUs, which may be carrying IP datagrams. See the discussion under SAR.
讨论：SCR限制ATM连接上的平均数据速率。如果用户违反SCR，可能会丢弃单元，导致单元丢失。这反过来会对AAL5 PDU产生负面影响，因为AAL5 PDU可能承载IP数据报。参见SAR下的讨论。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: A connection established via signaling.
定义：通过信令建立的连接。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A Switched VCC is one that is established and taken down dynamically through control signaling. A Virtual Channel Connection (VCC) is an ATM connection where switching is performed on the VPI/VCI fields of each cell.
定义：交换VCC是通过控制信令动态建立和取下的VCC。虚拟信道连接（VCC）是一种ATM连接，其中在每个信元的VPI/VCI字段上执行交换。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A connection established via signaling. The user defines the endpoints when the call is initiated.
定义：通过信令建立的连接。用户在启动调用时定义端点。
Discussion: SVCs are established using either UNI signaling or PNNI signaling. The signaling state machine implements several timers, which can effect the time required for call establishment. This will effect TCP round trip time calculation, effecting TCP throughput. Specifically, there are two possibilities. In the case where Call Proceeding is not implemented, there is only one timer, T310, with a value of 10 seconds. In the case where Call Proceeding is implemented, there are two timers, T303 and T310, with the values 4 and 10 seconds, respectively. In either case, if a timer, either T303 or T310, expires after a Setup message is send, the calling party has the option of re-transmitting the Setup. In the T303 case, this yields a maximum setup time of 18 seconds and, In the T310 case, a maximum setup time of 20 seconds. Thus, the initial TCP RTT calculation will be on he order of 20 seconds.
讨论：SVC使用UNI信令或PNNI信令建立。信令状态机实现多个定时器，这些定时器可以影响呼叫建立所需的时间。这将影响TCP往返时间计算，影响TCP吞吐量。具体来说，有两种可能性。在没有执行呼叫继续的情况下，只有一个值为10秒的计时器T310。在执行呼叫处理的情况下，有两个计时器T303和T310，其值分别为4秒和10秒。在任何一种情况下，如果定时器T303或T310在发送设置消息后过期，则主叫方可以选择重新发送设置。在T303情况下，最大设置时间为18秒，在T310情况下，最大设置时间为20秒。因此，初始TCP RTT计算将在20秒左右。
Specification: AF-UNI3.1, AF-UNI4.0, AF-PNNI1.0
规格：AF-UNI3.1、AF-UNI4.0、AF-PNNI1.0
Definition: A Switched Virtual Path Connection is one that is established and taken down dynamically through control signaling. A Virtual Path Connection (VPC) is an ATM connection where switching is performed on the VPI field only of each cell.
定义：交换虚拟路径连接是通过控制信令动态建立和断开的连接。虚拟路径连接（VPC）是一种ATM连接，其中交换仅在每个信元的VPI字段上执行。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A specification of the negotiated traffic characteristics of an ATM connection.
定义：ATM连接的协商流量特性规范。
Discussion: See discussions under BT, CAC, CDV, GCRA, PCR and SCR.
讨论：见BT、CAC、CDV、GCRA、PCR和SCR下的讨论。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: Traffic Management is the aspect of the traffic control and congestion control procedures for ATM. ATM layer traffic control refers to the set of actions taken by the network to avoid congestion conditions. ATM layer congestion control refers to the set of
定义：流量管理是ATM流量控制和拥塞控制程序的一个方面。ATM层流量控制是指网络为避免拥塞情况而采取的一系列措施。ATM层拥塞控制是指一组
actions taken by the network to minimize the intensity, spread and duration of congestion. The following functions form a framework for managing and controlling traffic and congestion in ATM networks and may be used in appropriate combinations.
网络为尽量减少拥挤的强度、蔓延和持续时间而采取的行动。以下功能构成了管理和控制ATM网络中流量和拥塞的框架，并可适当组合使用。
Connection Admission Control Feedback Control Usage Parameter Control Priority Control Traffic Shaping Network Resource Management Frame Discard ABR Flow Control
连接允许控制反馈控制使用参数控制优先级控制流量整形网络资源管理帧丢弃ABR流量控制
Discussion: See CAC and traffic shaping.
讨论：参见CAC和流量塑造。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: Traffic Shaping is a mechanism that alters the traffic characteristics of a stream of cells on a connection to achieve better network efficiency, while meeting the QoS objectives, or to ensure conformance at a subsequent interface. Traffic shaping must maintain cell sequence integrity on a connection. Shaping modifies traffic characteristics of a cell flow with the consequence of increasing the mean Cell Transfer Delay.
定义：流量整形是一种机制，它改变连接上小区流的流量特性，以实现更好的网络效率，同时满足QoS目标，或确保后续接口的一致性。流量整形必须在连接上保持小区序列的完整性。整形通过增加平均小区传输延迟来修改小区流的业务特性。
Discussion: TS should improve TCP throughput by reducing RTT variations. As a result, TCP RTT calculations should be more stable.
讨论：TS应该通过减少RTT变化来提高TCP吞吐量。因此，TCP RTT计算应该更加稳定。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A sub-layer of the physical layer of the B-ISDN model transforms the flow of cells into a steady flow of bits and bytes for transmission over the physical medium. On transmit the TC sublayer maps the cells to the frame format, generates the Header Error Check (HEC), and sends idle cells when the ATM layer has none. to send. On reception, the TC sublayer delineates individual cells in the received bit stream, and uses the HEC to detect and correct received errors.
定义：B-ISDN模型物理层的子层将信元流转换为稳定的比特流和字节流，以便在物理介质上传输。在传输时，TC子层将信元映射到帧格式，生成报头错误检查（HEC），并在ATM层没有空闲信元时发送空闲信元。发送。在接收时，TC子层描绘接收比特流中的单个小区，并使用HEC来检测和校正接收错误。
Discussion: TC is not a measurement, but the speed in which TC can occur on a bit stream can be measured. This measurement will not be discussed in this document; however, its value should be constant and small with respect to cell inter-arrival at the maximum data rate.
讨论：TC不是测量值，但可以测量TC在比特流上发生的速度。本文件不讨论该测量；然而，它的值应该是恒定的，并且相对于最大数据速率下的小区间到达而言很小。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: UBR is an ATM service category, which does not specify traffic related service guarantees. Specifically, UBR does not include the notion of a per-connection-negotiated bandwidth. No commitments are made with respect to the cell loss ratio experienced by a UBR connection, or as to the cell transfer delay experienced by cells on the connection.
定义：UBR是一个ATM服务类别，它不指定与流量相关的服务保证。具体而言，UBR不包括每个连接协商带宽的概念。对于UBR连接所经历的小区丢失率，或者对于连接上的小区所经历的小区传输延迟，没有做出任何承诺。
Discussion: RFC 2331 specifies UBR service class for IP over ATM. UBR service models the "best effort" service type specified in RFC 791; however, UBR has specific drawbacks with respect to TCP service. Since UBR makes no guarantee with respect to cell loss (CL), cell delay variation (CDV) or cell mis-insertion(CM), TCP RTT estimates will be highly variable. Further, all negatively impact AAL5 re-assembly, which in turn may cause packet loss. See discussions under CDV and SAR.
讨论：RFC2331为ATM上的IP指定了UBR服务类。UBR服务为RFC 791中规定的“尽力而为”服务类型建模；然而，UBR在TCP服务方面有特定的缺点。由于UBR不能保证小区丢失（CL）、小区延迟变化（CDV）或小区误插入（CM），TCP RTT估计值将是高度可变的。此外，所有这些都会对AAL5重新组装产生负面影响，进而可能导致数据包丢失。参见CDV和SAR下的讨论。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: Usage Parameter Control is defined as the set of actions taken by the network to monitor and control traffic, in terms of traffic offered and validity of the ATM connection, at the end-system access. Its main purpose is to protect network resources from malicious as well as unintentional misbehavior, which can affect the QoS of established connections, by detecting violations of negotiated parameters and taking appropriate actions.
定义：使用参数控制定义为网络在终端系统访问时，根据提供的流量和ATM连接的有效性，监控和控制流量所采取的一组操作。它的主要目的是通过检测对协商参数的违反并采取适当的措施，保护网络资源免受恶意和无意的不当行为的影响，这些行为可能会影响已建立连接的QoS。
Discussion: See discussions under BT, CAC, CDV, GCRA, PCR and SCR.
讨论：见BT、CAC、CDV、GCRA、PCR和SCR下的讨论。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: An interface point between ATM end users and a private ATM switch, or between a private ATM switch and the public carrier ATM network; defined by physical and protocol specifications per ATM Forum UNI documents. The standard adopted by the ATM Forum to define connections between users or end stations and a local switch.
定义：ATM终端用户与专用ATM交换机之间，或专用ATM交换机与公共运营商ATM网络之间的接口点；根据ATM论坛UNI文件的物理和协议规范定义。ATM论坛采用的标准，用于定义用户或终端站与本地交换机之间的连接。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: An ATM Forum defined service category which supports variable bit rate data traffic with average and peak traffic parameters.
定义：ATM论坛定义的服务类别，支持具有平均和峰值流量参数的可变比特率数据流量。
Discussion: VBR may potentially adversely effect TCP throughput due to large RTT variations. This in turn will cause the TCP RTT estimates to be unstable.
讨论：由于RTT变化较大，VBR可能会对TCP吞吐量产生潜在的负面影响。这反过来会导致TCP RTT估计值不稳定。
Specification: AF-TM4.0
规格：AF-TM4.0
Definition: A communications channel that provides for the sequential unidirectional transport of ATM cells.
定义：提供ATM信元顺序单向传输的通信信道。
Discussion: none.
讨论：无。
Specification: AF-TM3.1
规格：AF-TM3.1
Definition: A concatenation of VCIs that extends between the points where the ATM service users access the ATM layer. The points at which the ATM cell payload is passed to, or received from, the users of the ATM Layer (i.e., a higher layer or ATM-entity) for processing signify the endpoints of a VCC. VCCs are unidirectional.
定义：在ATM服务用户访问ATM层的点之间扩展的VCI串联。ATM信元有效载荷传递给或从ATM层（即，更高层或ATM实体）的用户接收以进行处理的点表示VCC的端点。VCC是单向的。
Discussion: none.
讨论：无。
Specification: AF-TM3.1
规格：AF-TM3.1
Definition: A unique numerical tag as defined by a 16 bit field in the ATM cell header that identifies a virtual channel, over which the cell is to travel.
定义：由ATM信元报头中的16位字段定义的唯一数字标记，用于标识信元将在其上传输的虚拟信道。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A unidirectional logical association or bundle of VCs.
定义：VCs的单向逻辑关联或捆绑。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
Definition: A concatenation of VPIs between Virtual Path Terminators (VPTs). VPCs are unidirectional
定义：虚拟路径终止符（VPT）之间VPI的串联。专有网络是单向的
Discussion: none.
讨论：无。
Specification: AF-TM3.1
规格：AF-TM3.1
Definition: An eight-bit field in the ATM cell header that indicates the virtual path over which the cell should be routed.
定义：ATM信元报头中的一个八位字段，指示信元应该路由到的虚拟路径。
Discussion: none.
讨论：无。
Specification: AF-UNI3.1
规格：AF-UNI3.1
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: Pointer Movements is the number of changes in a SONET pointer due to clock synchronization slips.
定义：指针移动是由于时钟同步滑动导致SONET指针发生变化的次数。
Discussion: SONET Pointer Movements can cause loss of information in the SONET payload envelop (SPE) which contains IP datagrams, either in the form of ATM cells or as PPP delimited PDUs.
讨论：SONET指针移动可能会导致SONET有效负载信封（SPE）中的信息丢失，SPE包含IP数据报，无论是以ATM信元的形式还是以PPP分隔的PDU的形式。
Measurement Units: Per second.
测量单位：每秒。
Definition: SONET Transport Overhead Error Count is the number of SONET transport overhead errors detected.
定义：SONET传输开销错误计数是检测到的SONET传输开销错误数。
Discussion: SONET Transport Overhead Errors SONET Transport Overhead Errors cause SONET frames to be lost. These frames may contain IP datagrams; either in the form of cells or as PPP delimited PDUs.
讨论：SONET传输开销错误SONET传输开销错误导致SONET帧丢失。这些帧可以包含IP数据报；以单元格形式或PPP分隔的PDU形式。
Measurement Units: Positive integer
计量单位：正整数
Definition: SONET Path Overhead Error Count is the number of SONET path overhead errors detected.
定义：SONET路径开销错误计数是检测到的SONET路径开销错误数。
Discussion: SONET Path Overhead Errors cause SONET frames to be lost. These frames may contain IP datagrams; either in the form of cells or as PPP delimited PDUs.
讨论：SONET路径开销错误导致SONET帧丢失。这些帧可以包含IP数据报；以单元格形式或PPP分隔的PDU形式。
Measurement Units: Positive integer
计量单位：正整数
Definition: The variation in cell transfer delay (CTD) associated with a given traffic load, orientation and distribution, as well as an integration period. CDV = max (CTD) - min (CTD) where max and min indicate the maximum and minimum over the integration period, respectively.
定义：与给定的业务负载、方向和分布以及集成周期相关的小区传输延迟（CTD）的变化。CDV=最大值（CTD）-最小值（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: CDV is a component of cell transfer delay, induced by buffering and cell scheduling. Peak-to-peak CDV is a QoS delay parameter associated with CBR and VBR services. The peak-to-peak CDV is the ((1-a) quantile of the CTD) minus the fixed CTD that could be experienced by any delivered cell on a connection during the entire connection holding time. The parameter "a" is the probability of a cell arriving late.
讨论：CDV是由缓冲和小区调度引起的小区传输延迟的一个组成部分。峰间CDV是与CBR和VBR服务相关联的QoS延迟参数。峰-峰CDV是（（1-a）CTD分位数）减去在整个连接保持时间内连接上任何交付的小区可能经历的固定CTD。参数“a”是单元延迟到达的概率。
CDV effects TCP round trip time calculations. Large values of CDV will adversely effect TCP throughput and cause SAR timeout. See discussion under SAR.
CDV影响TCP往返时间计算。较大的CDV值将对TCP吞吐量产生不利影响，并导致SAR超时。见SAR下的讨论。
Measurement Units: seconds
测量单位：秒
Definition: The ratio of cells with payload errors in a transmission in relation to the total number of cells sent in a transmission associated with a given traffic load, orientation and distribution, as well as an integration period. Note that errors occurring in the cell header will cause cell loss at the ATM layer. Note further that multiple errors in a payload will only be counted as one cell payload error.
定义：一次传输中存在有效负载错误的信元与一次传输中发送的信元总数的比率，该传输与给定的业务负载、方向和分布以及积分周期有关。请注意，信元报头中发生的错误将导致ATM层的信元丢失。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。
CER = Cells with payload errors / Total Cells Transmitted.
CER=有有效负载错误的小区/传输的小区总数。
Discussion: The measurement is taken over a time interval and is desirable to be measured on an in-service circuit. CER is closely related to the number of corrupted AAL5 PDUs; however, there is not a direct numerical correlation between the number of errored cells and the number of corrupted AAL5 PDUs. There are two cases described below.
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。CER与损坏的AAL5 PDU数量密切相关；然而，错误单元的数量与损坏的AAL5 PDU的数量之间没有直接的数值相关性。下面描述了两种情况。
1. Only one cell in an AAL5 PDU contains payload errors. In this case, there is a one-to-one correspondence between cell payload errors and the number of corrupted AAL5 PDUs.
1. AAL5 PDU中只有一个单元包含有效负载错误。在这种情况下，小区有效负载错误与损坏的AAL5 PDU数量之间存在一对一的对应关系。
2. Multiple cells in the AAL5 PDU contain payload errors. In this case, there is not a one-to-one correspondence between cell payload errors and the number of corrupted AAL5 PDUs.
2. AAL5 PDU中的多个单元包含有效负载错误。在这种情况下，小区有效负载错误与损坏的AAL5 PDU数量之间不存在一一对应关系。
Measurement Units: dimensionless.
测量单位：无量纲。
Definition: The ratio of lost cells in a transmission in relation to the total cells sent in a transmission associated with a given traffic load, orientation and distribution, as well as an integration period.
定义：传输中丢失的信元与传输中发送的总信元的比率，与给定的业务负载、方向和分布以及集成周期有关。
CLR = Lost Cells / Total Cells Transmitted.
CLR=丢失的单元/传输的单元总数。
Discussion: CLR is a negotiated QoS parameter and acceptable values are network specific. The objective is to minimize CLR provided the end-system adapts the traffic to the changing ATM layer transfer characteristics. The CLR parameter is the value of CLR that the network agrees to offer as an objective over the lifetime of the connection. It is expressed as an order of magnitude, having a range of 10^-1 to 10^-15 and unspecified.
讨论：CLR是一个协商的QoS参数，可接受的值是特定于网络的。目标是在终端系统使流量适应不断变化的ATM层传输特性的情况下，使CLR最小化。CLR参数是网络同意在连接生存期内作为目标提供的CLR值。它表示为一个数量级，范围为10^-1至10^-15，未指定。
CLR indicates the number of ATM cells lost in relation to the total number of cells sent. CLR is closely related to the number of corrupted AAL5 PDUs; however, there is not a direct numerical correlation between the number of cells lost and the number of corrupted AAL5 PDUs. See the discussion under SAR.
CLR表示丢失的ATM信元数与发送的信元总数的关系。CLR与损坏的AAL5 PDU数量密切相关；然而，丢失的单元数量与损坏的AAL5 PDU数量之间没有直接的数值相关性。参见SAR下的讨论。
Measurement Units: dimensionless.
测量单位：无量纲。
Definition: The ratio of cells received at an endpoint that were not originally transmitted by the source end in relation to the total number of 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、源端最初未传输的小区与正确传输的、与给定流量负载、方向和分布以及集成周期相关的小区总数的比率。
CMR = Misinserted Cells / Total Cells Transmitted.
CMR=错误插入的小区/传输的小区总数。
Discussion: The measurement is taken over a time interval and is desirable to be measured on an in-service circuit. CMR is closely related to the number of corrupted AAL5 PDUs; however, there is not a direct numerical correlation between the number of mis-inserted cells and the number of corrupted AAL5 PDUs. There are two cases described below.
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。CMR与损坏的AAL5 PDU数量密切相关；但是，错误插入的单元数量与损坏的AAL5 PDU数量之间没有直接的数值相关性。下面描述了两种情况。
1. Only one cell is mis-inserted into an AAL5 PDU. In this case, there is a one-to-one correspondence between cell mis-insertion and the number of corrupted AAL5 PDUs.
1. 只有一个单元错误插入AAL5 PDU。在这种情况下，单元错误插入和损坏的AAL5 PDU数量之间存在一对一的对应关系。
2. Multiple cells are mis-inserted into an AAL5. In this case, there is not a one-to-one correspondence between cell mis-insertion and the number of corrupted AAL5 PDUs.
2. 多个单元错误地插入到AAL5中。在这种情况下，单元错误插入与损坏的AAL5 PDU数量之间不存在一一对应关系。
Measurement Units: dimensionless.
测量单位：无量纲。
Definition: This is a measure of the difference between the effective bandwidth allocation and the allocation for sustainable rate in cells per second.
定义：这是有效带宽分配和可持续速率分配（以每秒小区为单位）之间差异的度量。
Discussion: This measures the amount of provisioned bandwidth which is not utilized. This lack of utilization may be caused by encapsulation overhead, e.g., AAL5 trailer and padding, or by the protocol itself, e.g., TCP usually transmits in only one direction.
讨论：这测量未使用的已调配带宽的数量。这种利用率不足可能是由封装开销（例如AAL5尾部和填充）或协议本身（例如TCP通常只在一个方向上传输）引起的。
Measurement units: Cells per second
测量单位：每秒单元数
Definition: The ratio of PDUs received at an endpoint that which contain an invalid CRC in relation to the total number of 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PDU相对于与给定流量负载、方向和分布以及集成周期相关的正确传输的小区总数的比率。
Discussion: CRC errors cause ATM cells to be lost. Although this will appear as cell loss at the ATM layer, this measurement can be made in-service using a test probe which measures CRC errors at the TC layer.
讨论：CRC错误导致ATM信元丢失。虽然这将在ATM层显示为信元丢失，但可以使用测试探针在服务中进行测量，该探针测量TC层的CRC错误。
Measurement Units: dimensionless
测量单位：无量纲
Definition: The elapsed time between a cell exit event at the measurement point 1 (e.g., at the source UNI) and the corresponding 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）处的小区退出事件与测量点2（例如，目标UNI）处的相应小区进入事件之间经过的时间。
Discussion: The 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. While this number is a constant and should not adversely effect performance, it is a component in RTT.
讨论：两个测量点之间的信元传输延迟是总ATM节点间传输延迟和总ATM节点处理延迟之和。虽然这个数字是一个常数，不会对性能产生不利影响，但它是RTT中的一个组成部分。
Measurement units: seconds
测量单位：秒
Definition: AAL5 Re-assembly Errors constitute any error, which causes the AAL5 PDU to be corrupted.
定义：AAL5重新组装错误构成任何导致AAL5 PDU损坏的错误。
Discussion: AAL5 Re-assembly errors cause AAL5 PDUs to be lost. These PDUs may contain IP datagrams.
讨论：AAL5重新组装错误导致AAL5 PDU丢失。这些PDU可能包含IP数据报。
Measurement Units: Positive Integer
计量单位：正整数
Definition: AAL5 Reassembly Time constitutes the time between the arrival of the final cell in the AAL5 PDU and the AAL5 PDUs payload being made available to the service layer.
定义：AAL5重新组装时间构成AAL5 PDU中的最终单元到达和服务层可用的AAL5 PDU有效载荷之间的时间。
Discussion: AAL5 Reassembly time directly effects TCP round trip time calculations.
讨论：AAL5重新组装时间直接影响TCP往返时间的计算。
Measurement Units: seconds
测量单位：秒
Definition: The ratio of PDUs received at an endpoint that which contain an invalid CRC in relation to the total number of 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PDU相对于与给定流量负载、方向和分布以及集成周期相关的正确传输的小区总数的比率。
Discussion: AAL5 CRC errors cause AAL5 re-assembly errors. See discussion under AAL5 re-assembly errors.
讨论：AAL5 CRC错误导致AAL5重新组装错误。请参阅AAL5重新组装错误下的讨论。
Measurement Units: dimensionless
测量单位：无量纲
Definition: The amount of time required for CAC to determine that a call must be rejected.
定义：CAC确定必须拒绝呼叫所需的时间量。
Discussion: In the case where Call Proceeding is implemented, this number will be less than 4 seconds. Otherwise, it will be less than 10 seconds. Large values of this measurement will adversely effect performance on systems where an alternate, non-NBMA, service is available.
讨论：在实施呼叫处理的情况下，该数字将少于4秒。否则，时间将少于10秒。该测量值的较大值将对有备用非NBMA服务的系统的性能产生不利影响。
Measurement Units: seconds
测量单位：秒
Definition: The amount of time between the first Setup message from the calling party and the Connect message to the calling party.
定义：从主叫方发出的第一条设置消息到连接到主叫方的消息之间的时间量。
Discussion: See discussion under SVC.
讨论：见SVC下的讨论。
Measurement Units: seconds
测量单位：秒
Definition: The amount of between the Release message being sent and the Release Complete message being received.
定义：发送的发布消息与接收的发布完成消息之间的间隔量。
Discussion: Large values of this measurement will adversely effect performance in systems where the total number of open calls or VCs is limited. Specifically, a new VC cannot be instantiated with the same VPI/VCI before the old one is released.
讨论：在开放呼叫或VCs总数有限的系统中，此测量值的较大值将对性能产生不利影响。具体来说，在旧VC发布之前，不能使用相同的VPI/VCI实例化新VC。
Measurement Units: seconds
测量单位：秒
Definition: The amount of time between the issuance of the first release or release complete message by the switch where the current Designated Transit List (DTL) is blocked and the receipt of the SETUP with the updated DTLs by the target switch.
定义：当前指定传输列表（DTL）被阻止的交换机发出第一次发布或发布完成消息与目标交换机收到带有更新DTL的设置之间的时间量。
Discussion: This measurement does not take into account the amount of time associated with either the successful portion of the call setup transit or the time required for the calling party to receive .bp a response from the called party. As a result, the call may still fail to complete if the call setup timer on the calling party expires.
讨论：此度量不考虑与呼叫设置传输成功部分相关的时间量，也不考虑呼叫方接收.bp被叫方响应所需的时间量。因此，如果呼叫方的呼叫设置计时器过期，则呼叫仍可能无法完成。
See discussion under SVC.
参见SVC下的讨论。
Measurement Units: seconds
测量单位：秒
Definition: The amount of time between the receipt of a PNNI Topology State Element (PTSE), which is the PNNI routing PDU, containing a topology different from the current topology and the point at which the switch begins to generate DTLs reflecting the routing change.
定义：从接收到PNNI拓扑状态元素（PTSE）（即PNNI路由PDU，包含与当前拓扑不同的拓扑）到交换机开始生成反映路由更改的DTL之间的时间量。
Discussion: This measurement provides a lower bound on the amount of time during which SETUP messages will be forwarded along a sub-optimal or blocked path.
讨论：此度量提供了设置消息沿次优或阻塞路径转发的时间量下限。
Measurement Units: seconds
测量单位：秒
Definition: The amount of time between the issuance of the final cold start message and the final get response associated with the exchange of static MIB information.
定义：发出最终冷启动消息和与静态MIB信息交换相关的最终get响应之间的时间量。
Discussion: This measurement reflects the amount of time required by the switch and end system to exchange all information required to characterize and align the capabilities of both systems. It does not include address registration. It should also be noted that this measurement will depend on the number of MIB elements implemented by both systems.
讨论：该度量反映了交换机和终端系统交换描述和调整两个系统功能所需的所有信息所需的时间量。它不包括地址注册。还应注意，该测量将取决于两个系统实现的MIB元素的数量。
Measurement Units: seconds
测量单位：秒
Definition: The amount of time between the initial set request issued by the switch and the final get response issued by the switch.
定义：从开关发出的初始设置请求到开关发出的最终get响应之间的时间量。
Discussion: This measurement assumes that the switch has checked the network prefix status object and the end system has checked the ATM address status object. In the case where the end system checks the ATM address status object only after the switch has issued a set request of the network prefix status object, this measurement will not reflect the actual time required to complete the address registration.
讨论：此测量假设交换机已检查网络前缀状态对象，终端系统已检查ATM地址状态对象。如果终端系统仅在交换机发出网络前缀状态对象的设置请求后才检查ATM地址状态对象，则该测量将不会反映完成地址注册所需的实际时间。
Measurement Units: seconds
测量单位：秒
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[AF-ILMI4.0] ATM Forum Integrated Local Management Interface Version 4.0, af-ilmi-0065.000, September 1996.
[AF-ILMI4.0]ATM论坛集成本地管理接口版本4.0，AF-ilmi-0065.000，1996年9月。
[AF-TEST-0022] Introduction to ATM Forum Test Specifications, af-test-0022.00, December 1994.
[AF-TEST-0022]ATM论坛测试规范介绍，AF-TEST-0022.002994年12月。
[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 (final ballot), btd-tm-01.02, July 1998.
[AF-TM4.1]ATM论坛，交通管理规范版本4.1（最终投票），btd-tm-01.021998年7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。
[I.321] ITU-T, B-ISDN protocol reference model and its application, April 1991.
[I.321]ITU-T，B-ISDN协议参考模型及其应用，1991年4月。
[I.363] ITU-T, B-ISDN ATM Adaptation Layer Specification series, 1996-1997.
[I.363]ITU-T，B-ISDN ATM适配层规范系列，1996-1997。
[I.363.5] ITU-T, B-ISDN ATM Adaptation Layer Specification: Type 5 AAL, August 1996.
[I.363.5]ITU-T，B-ISDN ATM适配层规范：类型5 AAL，1996年8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. 11241-B Skilift Court Columbia, MD 21044 USA
Cynthia Martin Advanced Network Consultants，Inc.美国马里兰州哥伦比亚Skilift Court 11241-B 21044
Phone: +1 (410) 730-6300
EMail: Cynthia.E.Martin@worldnet.att.net
Phone: +1 (410) 730-6300
EMail: Cynthia.E.Martin@worldnet.att.net
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Acknowledgement
确认
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