Independent Submission B. Berry, Ed.
Request for Comments: 5578 S. Ratliff
Obsoletes: 4938 E. Paradise
Category: Informational Cisco
ISSN: 2070-1721 T. Kaiser
Harris Corporation
M. Adams
L3 Communications
February 2010
Independent Submission B. Berry, Ed.
Request for Comments: 5578 S. Ratliff
Obsoletes: 4938 E. Paradise
Category: Informational Cisco
ISSN: 2070-1721 T. Kaiser
Harris Corporation
M. Adams
L3 Communications
February 2010
PPP over Ethernet (PPPoE) Extensions for Credit Flow and Link Metrics
用于信用流量和链路指标的以太网PPP（PPPoE）扩展
Abstract
摘要
This document extends the Point-to-Point Protocol over Ethernet (PPPoE) with an optional credit-based flow control mechanism and an optional Link Quality Metric report. These optional extensions improve the performance of PPPoE over media with variable bandwidth and limited buffering, such as mobile point-to-point radio links.
本文档通过可选的基于信用的流量控制机制和可选的链路质量度量报告扩展了以太网点对点协议（PPPoE）。这些可选扩展通过具有可变带宽和有限缓冲的媒体（如移动点对点无线链路）提高PPPoE的性能。
Status of This Memo
关于下段备忘
This document is not an Internet Standards Track specification; it is published for informational purposes.
本文件不是互联网标准跟踪规范；它是为了提供信息而发布的。
This is a contribution to the RFC Series, independently of any other RFC stream. The RFC Editor has chosen to publish this document at its discretion and makes no statement about its value for implementation or deployment. Documents approved for publication by the RFC Editor are not a candidate for any level of Internet Standard; see Section 2 of RFC 5741.
这是对RFC系列的贡献，独立于任何其他RFC流。RFC编辑器已选择自行发布此文档，并且未声明其对实现或部署的价值。RFC编辑批准发布的文件不适用于任何级别的互联网标准；见RFC 5741第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc5578.
有关本文件当前状态、任何勘误表以及如何提供反馈的信息，请访问http://www.rfc-editor.org/info/rfc5578.
IESG Note
IESG注释
The PPP Extensions Working Group (PPPEXT) has reservations about the desirability of the feature described in this document. In particular, it solves a general problem at an inappropriate layer and it may have unpredictable interactions with higher and lower level protocols. The techniques described in this document are intended for use with a particular deployment technique that uses a PPP termination separated from a radio termination by an Ethernet, and that has radio-side flow control for a slower PPP-only link to remote
PPP扩展工作组（PPPEXT）对本文件所述功能的可取性持保留意见。特别是，它在一个不合适的层上解决了一个一般问题，并且它可能与更高和更低级别的协议进行不可预测的交互。本文档中描述的技术旨在与特定部署技术一起使用，该部署技术使用通过以太网与无线电终端分离的PPP终端，并且具有用于较慢的仅PPP链接到远程的无线电侧流控制
nodes. Implementors are better advised to avoid split termination with inter-media protocol translation, and use standard Internet Protocol routing instead.
节点。最好建议实施者避免使用媒体间协议转换进行拆分终止，而是使用标准的Internet协议路由。
Copyright Notice
版权公告
Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2010 IETF信托基金和确定为文件作者的人员。版权所有。
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http:trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document.
本文件受BCP 78和IETF信托有关IETF文件的法律规定（http:truster.IETF.org/license info）的约束，这些法律规定在本文件出版之日生效。请仔细阅读这些文件，因为它们描述了您对本文件的权利和限制。
Table of Contents
目录
1. Introduction ....................................................3
2. Terminology .....................................................4
3. Overview of Protocol Extensions .................................5
3.1. TLVs .......................................................5
3.1.1. Credits TLV .........................................5
3.1.2. Metrics TLV .........................................6
3.1.3. Sequence Number TLV .................................7
3.1.4. Credit Scale Factor TLV .............................8
3.2. Discovery Stage Extensions .................................8
3.2.1. PPPoE Active Discovery Request (PADR) ...............9
3.2.2. PPPoE Active Discovery Session-Confirmation
(PADS) .............................................11
3.2.3. PPPoE Active Discovery Session-Grant (PADG) ........13
3.2.4. PPPoE Active Discovery Session-Credit
Response (PADC) ....................................15
3.2.5. PPPoE Active Discovery Quality (PADQ) ..............16
3.3. PPP Session Stage Extensions ..............................18
4. Credit Flow Considerations .....................................19
5. PADG and PADC Retransmission ...................................20
6. Other Considerations ...........................................20
7. IANA Considerations ............................................21
8. Security Considerations ........................................21
9. References .....................................................21
9.1. Normative References ......................................21
9.2. Informative References ....................................21
Appendix A. Examples of Session Credit Flows ......................22
1. Introduction ....................................................3
2. Terminology .....................................................4
3. Overview of Protocol Extensions .................................5
3.1. TLVs .......................................................5
3.1.1. Credits TLV .........................................5
3.1.2. Metrics TLV .........................................6
3.1.3. Sequence Number TLV .................................7
3.1.4. Credit Scale Factor TLV .............................8
3.2. Discovery Stage Extensions .................................8
3.2.1. PPPoE Active Discovery Request (PADR) ...............9
3.2.2. PPPoE Active Discovery Session-Confirmation
(PADS) .............................................11
3.2.3. PPPoE Active Discovery Session-Grant (PADG) ........13
3.2.4. PPPoE Active Discovery Session-Credit
Response (PADC) ....................................15
3.2.5. PPPoE Active Discovery Quality (PADQ) ..............16
3.3. PPP Session Stage Extensions ..............................18
4. Credit Flow Considerations .....................................19
5. PADG and PADC Retransmission ...................................20
6. Other Considerations ...........................................20
7. IANA Considerations ............................................21
8. Security Considerations ........................................21
9. References .....................................................21
9.1. Normative References ......................................21
9.2. Informative References ....................................21
Appendix A. Examples of Session Credit Flows ......................22
PPP over Ethernet (PPPoE) [2] is a protocol for establishing and encapsulating sessions between Hosts (Clients) and traffic-access aggregators (Servers) for PPP [1] transport over real or emulated Ethernet. PPPoE works well when both session endpoints have similar bandwidth, forwarding, and buffering capabilities that do not vary over time. However, improvements can be made for applications with variable bandwidth and limited buffering. This document addresses these improvements with optional extensions to PPPoE that support credit-based session flow control and session-based link metric quality reports.
以太网PPP（PPPoE）[2]是一种协议，用于在主机（客户端）和流量访问聚合器（服务器）之间建立和封装会话，以便通过真实或模拟以太网进行PPP[1]传输。当两个会话端点具有相似的带宽、转发和缓冲能力且不随时间变化时，PPPoE工作良好。但是，对于带宽可变且缓冲有限的应用程序，可以进行改进。本文档通过支持基于信用的会话流控制和基于会话的链路度量质量报告的PPPoE可选扩展来解决这些改进。
These extensions are designed to support radio systems that exhibit point-to-point waveforms. The diagram below is used to illustrate the improvement that these extensions address. When the local Client (Radio) detects the presence of a remote Radio neighbor, it initiates a PPPoE session with its local Server (router). The Radio also establishes a radio link connection with the remote Radio over the point-to-point RF (radio frequency) link (which is beyond the scope of this document). The remote Radio is also establishing a PPPoE session with its local Server (router). The Radios associate the two PPPoE sessions and the point-to-point radio link protocol (RLP), creating a complete data path. Now a PPP session is established via the PPP IP Control Protocol (IPCP) as described in RFC 1661. Included in this IPCP exchange is the router IP address. With the exchange of the IPCP IP addresses, each router inserts the remote IP address into its local routing tables. Note that the radio IP information is not inserted into the routing tables.
这些扩展旨在支持显示点对点波形的无线电系统。下图用于说明这些扩展所解决的改进。当本地客户端（无线电）检测到远程无线电邻居的存在时，它将启动与其本地服务器（路由器）的PPPoE会话。无线电还通过点对点RF（射频）链路（不在本文件范围内）与远程无线电建立无线电链路连接。远程无线电也正在与其本地服务器（路由器）建立PPPoE会话。无线电将两个PPPoE会话与点对点无线电链路协议（RLP）相关联，从而创建完整的数据路径。现在，如RFC1661所述，通过PPP IP控制协议（IPCP）建立PPP会话。此IPCP交换中包括路由器IP地址。通过交换IPCP IP地址，每个路由器将远程IP地址插入其本地路由表。请注意，无线IP信息不会插入路由表中。
|-----Local Neighbor-----| |-----Remote Neighbor----|
|-----Local Neighbor-----| |-----Remote Neighbor----|
+--------+ +-------+ +-------+ +--------+
| Router |=======| Radio |{~~~~~~~~}| Radio |=======| Router |
| Server | | Client| | Client| | Server |
+--------+ +-------+ +-------+ +--------+
+--------+ +-------+ +-------+ +--------+
| Router |=======| Radio |{~~~~~~~~}| Radio |=======| Router |
| Server | | Client| | Client| | Server |
+--------+ +-------+ +-------+ +--------+
| | | | | |
|-PPPoE-| |----RLP---| |-PPPoE-|
| |
|-----------PPP IPCP (IP Address)---------|
| |
|-------------PPP Data Session-------------|
| | | | | |
|-PPPoE-| |----RLP---| |-PPPoE-|
| |
|-----------PPP IPCP (IP Address)---------|
| |
|-------------PPP Data Session-------------|
Figure 1: PPPoE Network
图1：PPPoE网络
The capabilities of the RF links between RLP neighbors will vary over time due to mobility and environmental conditions as well as changes in the RF waveforms and encoding. To reflect these dynamic changes, the Radio may periodically generate Link Quality Metrics to the router. The router uses the link metric to update route costs and influence route selection. The influence upon the routing protocols is beyond the scope of this document.
由于移动性和环境条件以及射频波形和编码的变化，RLP邻居之间的射频链路的能力将随时间而变化。为了反映这些动态变化，无线电可以周期性地生成到路由器的链路质量度量。路由器使用链路度量来更新路由成本并影响路由选择。对路由协议的影响超出了本文档的范围。
A PPPoE Client implementation can be found at [3]. It is open source (GNU GPLv2 -- General Public License).
PPPoE客户端实现可在[3]中找到。它是开源的（GNUGPLv2——通用公共许可证）。
Access Concentrator The RFC 2516 term used to describe the Server. This document uses the terms Router or Server instead.
访问集中器RFC2516术语，用于描述服务器。本文档使用术语“路由器”或“服务器”。
BCN Backward Credit Notification. The BCN represents the number of remaining credits at the local node that were granted by peer node. The local node uses these credits to transmit payload back to the peer node. BCN ranges from 0-65535.
BCN反向信用通知。BCN表示对等节点在本地节点上授予的剩余信用数。本地节点使用这些信用将有效负载传输回对等节点。BCN的范围为0-65535。
CDR The Current Datarate.
CDR当前数据速率。
FCN Forward Credit Notification. The FCN represents the credits that the local node is granting to the peer node. The peer node uses these granted credits to transmit payload back to the local node. FCN ranges from 0-65535.
FCN转发信用通知。FCN表示本地节点授予对等节点的信用。对等节点使用这些授予的信用将有效负载发送回本地节点。FCN的范围为0-65535。
Gbit/s gigabits (1,000,000,000) per second.
每秒千兆比特（100000000）。
Host The RFC 2516 term used to describe the Server. This document uses the terms Radio or Client.
主机RFC2516术语，用于描述服务器。本文档使用术语无线电或客户端。
kbit/s kilobits (1,000) per second.
每秒千比特（1000）。
LCP PPP Link Control Protocol, RFC 1661.
LCP PPP链路控制协议，RFC1661。
Mbit/s megabits (1,000,000) per second.
Mbit/s兆位（1000000）每秒。
MDR The Maximum Datarate.
MDR最大数据速率。
NCP PPP Network Control Protocol, RFC 1661.
NCP PPP网络控制协议，RFC1661。
RLP Radio Link Protocol.
无线链路协议。
TAG The RFC 2516 PPPoE synonym for TLV. This document uses TLV.
将RFC 2516 PPPoE标记为TLV的同义词。本文档使用TLV。
Tbit/s terabits (1,000,000,000,000) per second.
每秒兆比特（100000000000）。
TLV Type-Length-Value.
TLV类型长度值。
The extensions consist of optional TLVs as well as enhanced and newly defined Discovery packets. The enhancements are applied to the Discovery Stage and the PPP Session Stage.
扩展包括可选的TLV以及增强的和新定义的发现数据包。这些增强应用于发现阶段和PPP会话阶段。
The new TLVs are listed in the table below:
下表列出了新的TLV：
TLV TLV
Value Description
=========================================
0x0106 Credits TLV
0x0107 Metrics TLV
0x0108 Sequence Number TLV
0x0109 Credit Scale Factor TLV
TLV TLV
Value Description
=========================================
0x0106 Credits TLV
0x0107 Metrics TLV
0x0108 Sequence Number TLV
0x0109 Credit Scale Factor TLV
This TLV contains the Forward Credit Notification (FCN) and the Backward Credit Notification (BCN). The Credits TLV is optional with the PADR (PPPoE Active Discovery Request) and PADS (PPPoE Active Discovery Session-Confirmation) and required in the PADG (PPPoE Active Discovery Session Grant) and PADC (PPPoE Active Discovery Session-Credit) Discovery packets (ETHER_TYPE=8863).
此TLV包含正向信用通知（FCN）和反向信用通知（BCN）。积分TLV对于PADR（PPPoE主动发现请求）和PADS（PPPoE主动发现会话确认）是可选的，并且在PADG（PPPoE主动发现会话授权）和PADC（PPPoE主动发现会话积分）发现数据包（ETHER_TYPE=8863）中是必需的。
The Credits TLV is optionally carried in the PPPoE data payload packet of the PPP Stage (ETHER_TYPE=8864).
信用TLV可选地在PPP阶段的PPPoE数据有效载荷分组中携带（以太类型=8864）。
The FCN represents the number of credits being granted by the local node to the peer node. The BCN represents the number of credits remaining at the local node that were granted by the peer node.
FCN表示本地节点授予对等节点的信用数。BCN表示对等节点授予的本地节点上剩余的信用数。
The Credits TLV is shown below:
学分TLV如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credits TLV = 0x0106 | TLV Length = 0x04 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCN | BCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credits TLV = 0x0106 | TLV Length = 0x04 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCN | BCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
These fields are transmitted in network byte order. The same byte order is used throughout the document in other structures as well.
这些字段以网络字节顺序传输。在其他结构的文档中也使用相同的字节顺序。
The Metrics TLV is used to report the link-quality parameters. The Metrics TLV is required with the PADQ (PPPoE Discovery Quality) Discovery packet.
指标TLV用于报告链路质量参数。PADQ（PPPoE发现质量）发现数据包需要度量TLV。
The Metrics TLV contains the following fields:
度量TLV包含以下字段：
Resources - a percentage, 0-100, representing the amount of remaining or available resources, such as battery power. If resources cannot be calculated, a value of 100 should be reported.
资源-百分比，0-100，表示剩余或可用资源的数量，如电池电量。如果无法计算资源，则应报告值100。
Relative Link Quality (RLQ) - a non-dimensional number, 0-100, representing the relative link quality. A value of 100 represents a link of the highest quality. If the RLQ cannot be calculated, a value of 100 should be reported.
相对链路质量（RLQ）-表示相对链路质量的无量纲数字，0-100。值100表示具有最高质量的链接。如果无法计算RLQ，则应报告值100。
Receive only - a bit that indicates whether the link is bi-directional or receive-only. A value of "1" indicates that the link is receive-only.
仅接收-指示链路是双向的还是仅接收的位。值“1”表示链路仅接收。
Reserved - reserved fields are zeroed unless otherwise specified.
保留-保留字段为零，除非另有规定。
CD - two bits that designate the units of the Current Datarate.
CD—指定当前数据速率单位的两位。
CD Scale: 00 == kbit/s (default)
01 == Mbit/s
10 == Gbit/s
11 == Tbit/s
CD Scale: 00 == kbit/s (default)
01 == Mbit/s
10 == Gbit/s
11 == Tbit/s
MD - two bits that designate the units of the Maximum Datarate.
MD—指定最大数据速率单位的两位。
MD Scale: 00 == kbit/s (default)
01 == Mbit/s
10 == Gbit/s
11 == Tbit/s
MD Scale: 00 == kbit/s (default)
01 == Mbit/s
10 == Gbit/s
11 == Tbit/s
Current Datarate - the Current Datarate, in un-scaled units per second, achieved on the RLP link. If the Radio makes no distinction between Maximum Datarate and Current Datarate, Current Datarate should equal the Maximum Datarate. When metrics are reported, the Current Datarate must be reported. The Current Datarate must be less than or equal to the Maximum Datarate.
当前数据速率-在RLP链路上实现的当前数据速率，以每秒未缩放单位表示。如果收音机不区分最大数据速率和当前数据速率，则当前数据速率应等于最大数据速率。报告指标时，必须报告当前数据速率。当前数据速率必须小于或等于最大数据速率。
Latency - the transmission delay that a packet encounters as it is transmitted over the link. This is reported in absolute delay, milliseconds. If latency cannot be calculated, a value of 0 should be reported. The calculation of latency is Radio dependent. For example, the latency may be a running average calculated from the internal queuing.
延迟-数据包在链路上传输时遇到的传输延迟。这是以绝对延迟（毫秒）为单位报告的。如果无法计算延迟，则应报告值0。延迟的计算取决于无线电。例如，延迟可以是从内部队列计算的运行平均值。
Maximum Datarate - the maximum theoretical data rate, in un-scaled units per second, that the RLP link is capable of providing. When metrics are reported, the Maximum Datarate must be reported.
最大数据速率-RLP链路能够提供的最大理论数据速率，以每秒未缩放单位表示。报告指标时，必须报告最大数据速率。
The Metrics TLV is shown below:
指标TLV如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metrics TLV = 0x0107 | TLV Length = 0x0A |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | MD| CD|R| RLQ | Resources |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Latency (MS) | Current Datarate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Datarate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metrics TLV = 0x0107 | TLV Length = 0x0A |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | MD| CD|R| RLQ | Resources |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Latency (MS) | Current Datarate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Datarate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This TLV is used to carry a unique 16-bit sequence number in order to identify a specific request and the associated response. The sequence number should be initialized to zero and incremented by one for each new request. For retransmitted packets, the same sequence number that was used in the previous packet transmission is repeated. The PADG and PADC packets require the Sequence Number Tag.
该TLV用于携带唯一的16位序列号，以便识别特定请求和相关响应。序列号应初始化为零，并为每个新请求递增1。对于重新传输的数据包，重复先前数据包传输中使用的相同序列号。PADG和PADC数据包需要序列号标签。
The Sequence Number TLV is shown below:
序列号TLV如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number TLV = 0x0108 | TLV Length = 0x02 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number TLV = 0x0108 | TLV Length = 0x02 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This TLV contains the scale factor value that is to be applied to the session credit calculations. The Credit Scale Factor TLV is optional with the PADR and PADS packets. Once the session is established with specified scale factors, the scale factors are set for the entire session. The scale factor value represents the units that the local node grants to the remote node. The remote node is responsible for maintaining the credit accounting relative to the data flow back to the local node.
此TLV包含将应用于会话信用计算的比例因子值。对于PADR和PADS数据包，信用比例因子TLV是可选的。使用指定的比例因子建立会话后，将为整个会话设置比例因子。比例因子值表示本地节点授予远程节点的单位。远程节点负责维护与返回到本地节点的数据流相关的信用记帐。
The Credit Scale Factor TLV can be used to change from the default 64-byte credit unit during the PADR-PADS exchange. The credit scale factor value can range from 1 byte to 65535 bytes. A zero value is ignored and the default 64-byte unit remains set. The scale factor is set per each payload flow: peer-to-local and local-to-peer.
在PADR-PADS交换过程中，信用比例因子TLV可用于更改默认的64字节信用单位。信用比例因子值的范围从1字节到65535字节。忽略零值，默认64字节单位保持设置。比例因子是根据每个有效负载流设置的：对等本地和本地对等。
The Credit Scale Factor TLV is shown below:
信贷规模系数TLV如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit Scale Factor = 0x0109 | TLV Length = 0x02 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Scale Factor Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit Scale Factor = 0x0109 | TLV Length = 0x02 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Scale Factor Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The specifications of the PPPoE Active Discovery Request (PADR) and the PPPoE Active Discovery Session-confirmation (PADS) packets are extended to include the optional Credits TLV and the Credit Scale Factor TLV. The PPPoE Active Discovery Session-Grant (PADG) packet, the PPPoE Active Discovery Session-Credit Response (PADC), and the Quality packets are newly defined Discovery Stage packets.
PPPoE主动发现请求（PADR）和PPPoE主动发现会话确认（PADS）包的规范被扩展，以包括可选的信用TLV和信用比例因子TLV。PPPoE主动发现会话授权（PADG）数据包、PPPoE主动发现会话信用响应（PADC）和质量数据包是新定义的发现阶段数据包。
Discovery
Packet Status
=======================================================
PADR Enhanced Optionally includes the Credits
TLV and the Credit Scale Factor
TLV
Discovery
Packet Status
=======================================================
PADR Enhanced Optionally includes the Credits
TLV and the Credit Scale Factor
TLV
PADS Enhanced Optionally includes the Credits TLV and the Credit Scale Factor TLV
PADS增强可选地包括信用TLV和信用比例因子TLV
PADG New Includes the Credits TLV and the Sequence Number TLV
PADG New包括学分TLV和序列号TLV
PADC New Includes the Credits TLV and the Sequence Number TLV
PADC New包括学分TLV和序列号TLV
PADQ New Includes the Metrics TLV
PADQ新增包括TLV指标
The PADR packet is extended to optionally contain a single Credits TLV, indicating that the Client requests credit flow control for this session. The Credits TLV contains the Forward Credit Notification (FCN) and the Backward Credit Notification (BCN) to be applied to the PPP Session Stage. The FCN provides the initial credits granted to the Server by the Client. The BCN value is set to 0, as the Client has not yet been granted credits from the Server.
PADR数据包被扩展为可选地包含一个Credits TLV，表示客户端请求此会话的信用流控制。信用TLV包含应用于PPP会话阶段的前向信用通知（FCN）和后向信用通知（BCN）。FCN提供客户端授予服务器的初始信用。BCN值设置为0，因为客户端尚未从服务器获得信用。
The PADR packet is enhanced to optionally contain a single Credit Scale Factor TLV. The Credit Scale Factor TLV defines the credit scale factor value. If the Credit Scale Factor TLV is omitted, the default 64-byte value is used for the session. When the Client includes the optional Credit Scale Factor TLV in the PADR, this credit scale factor value is applied to all credit grants associated with the Client credits that are granted to the Server.
PADR数据包经过增强，可以选择包含单个信用比例因子TLV。信贷规模因子TLV定义信贷规模因子值。如果省略了信用比例因子TLV，则会话将使用默认的64字节值。当客户端在PADR中包括可选的信用比例因子TLV时，此信用比例因子值将应用于与授予服务器的客户端信用相关联的所有信用授予。
The Server must echo the Credit Scale Factor TLV in the PADS response to confirm the credit scaling session and to designate the Server credit scaling factor. This PADS Credit Scaling Factor TLV represents the scale factor value that is applied to all credits granted from the Server to the Client.
服务器必须在PADS响应中回显信用比例因子TLV，以确认信用比例会话并指定服务器信用比例因子。此PADS Credit Scaling Factor TLV表示应用于从服务器授予客户端的所有信用的比例因子值。
Once the session is established during the PADR-PADS exchange, the credit scale factor value cannot be changed.
一旦在PADR-PADS交换期间建立会话，则不能更改信用等级系数值。
A Discovery PADR packet with the optional Credits TLV is shown below:
具有可选信用TLV的Discovery PADR数据包如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x19 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x0C |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = 0x0101 | Metrics TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credits TLV = 0x0106 | TLV Length = 0x04 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCN | BCN = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x19 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x0C |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = 0x0101 | Metrics TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credits TLV = 0x0106 | TLV Length = 0x04 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCN | BCN = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The credit units are expressed in the default 64-byte units.
信用单位以默认的64字节单位表示。
A Discovery PADR packet with the optional Credits TLV and the optional Credit Scale Factor TLV is shown below:
具有可选信用额TLV和可选信用比例因子TLV的Discovery PADR数据包如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x19 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = 0x0101 | TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credits TLV = 0x0106 | TLV Length = 0x04 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCN | BCN = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit Scale Factor = 0x0109 | TLV Length = 0x02 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| scale factor value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x19 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = 0x0101 | TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credits TLV = 0x0106 | TLV Length = 0x04 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCN | BCN = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit Scale Factor = 0x0109 | TLV Length = 0x02 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| scale factor value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Credits TLV FCN value is expressed in units of the session's credit scale factor value.
学分TLV FCN值以会话的学分比例因子值为单位表示。
The Server PADS is extended to optionally contain a single Credits TLV, indicating the Forward Credit Notification (FCN) and the Backward Credit Notification (BCN) of the PPP Session Stage.
服务器PAD扩展为可选地包含单个信用TLV，指示PPP会话阶段的前向信用通知（FCN）和后向信用通知（BCN）。
If the Client PADR contained a Credits TLV, then the Server PADS must indicate support for credit flow control by including a Credits TLV. The PADS Credits TLV FCN represents the number of credits initially granted to the Client. The Credits TLV BCN is an echo of the number of credits that the Client had granted to the Server in the originating PADR packet.
如果客户端PADR包含Credits TLV，则服务器PAD必须通过包含Credits TLV来指示对信用流控制的支持。PADS Credits TLV FCN表示最初授予客户的信用数。Credits TLV BCN是客户端在原始PADR数据包中授予服务器的信用数的回音。
Exchange of the Credits TLV in the PADR and PADS indicates that credit flow control is supported by both the Server and the Client for the designated PPP Session Stage. This is binding and must be
PADR和PADS中信用TLV的交换表明，对于指定的PPP会话阶段，服务器和客户端都支持信用流控制。这是有约束力的，必须加以修改
followed for the entire duration of the PPP Session Stage. A session's credit binding must be established prior to any other credit indications being exchanged.
在PPP会话阶段的整个持续时间内进行跟踪。在交换任何其他信用指示之前，必须建立会话的信用约束。
The Server PADS should only include the Credits TLV in response to a Client PADR that included the Credits TLV. If the Server does not support credit flow, it should not include the Credits TLV in its PADS response. The Client must terminate a credit-based session that cannot be supported by the Server. A Credits TLV transmitted outside an established credit-based session must be ignored.
服务器PAD应仅包含Credits TLV，以响应包含Credits TLV的客户端PADR。如果服务器不支持信用流，则不应在其PADS响应中包含信用TLV。客户端必须终止服务器不支持的基于信用的会话。必须忽略在已建立的基于信用的会话之外传输的信用TLV。
The Server PADS is enhanced to optionally contain a single Credit Scale Factor TLV. The Credit Scale Factor TLV defines the credit scale unit value. The Credit Scale Factor TLV must be included if it was included in the Client PADR. If the Credits TLV was not included in the originating PADR, it must be omitted, indicating that the 64-byte default is used for the directional flow. This credit scale factor is applied to Server grants to the Client.
服务器PAD经过增强，可以选择包含单个信用比例因子TLV。信用等级系数TLV定义信用等级单位值。如果客户PADR中包含信贷规模系数TLV，则必须将其包括在内。如果起始PADR中未包含信用TLV，则必须省略该信用TLV，这表明定向流使用64字节默认值。此信用比例因子应用于向客户端授予的服务器许可。
A Discovery PADS packet with the optional Credits TLV is shown below:
具有可选信用TLV的Discovery PADS数据包如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x65 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x0C |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = 0x0101 | TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credits TLV = 0x0106 | TLV Length = 0x04 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCN | BCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x65 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x0C |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = 0x0101 | TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credits TLV = 0x0106 | TLV Length = 0x04 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCN | BCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The BCN is expressed in the default 64-byte units.
BCN以默认的64字节单位表示。
A Discovery PADS packet with the optional Credits TLV and the optional Credit Scale Factor TLV is shown below:
具有可选信用额TLV和可选信用比例因子TLV的Discovery PADS数据包如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x65 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = 0x0101 | TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credits TLV = 0x0106 | TLV Length = 0x04 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCN | BCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit Scale Factor = 0x0109 | TLV Length = 0x02 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| scale factor value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x65 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = 0x0101 | TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credits TLV = 0x0106 | TLV Length = 0x04 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCN | BCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit Scale Factor = 0x0109 | TLV Length = 0x02 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| scale factor value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Credits TLV BCN value is expressed in units of the session scale factor value received in the PADR.
学分TLV BCN值以PADR中接收的会话比例因子值为单位表示。
The PPPoE Active Discovery Session-Grant (PADG) is a new packet defined in this specification. The local node (Server or Client) may send a PADG at any time after the PADR/PADS exchange to grant incremental flow control credits to a peer. The CODE field is set to 0x0A and the SESSION_ID must be set to the unique value generated for this PPPoE Session.
PPPoE主动发现会话授权（PADG）是本规范中定义的新数据包。本地节点（服务器或客户端）可在PADR/PADS交换后的任何时间发送PADG，以向对等方授予增量流量控制信用。代码字段设置为0x0A，会话ID必须设置为此PPPoE会话生成的唯一值。
Each flow control credit corresponds to the amount of PPP payload bytes that can be sent or received. For example, if the default credit scale factor of 64 bytes is used, and 128 bytes of PPP payload data are sent, then 2 credits would be consumed. When calculating credits to consume, all credit calculations must be rounded up. If, in the previous example, 130 bytes of PPP payload data were sent, 3 credits would have been consumed.
每个流控制信用对应于可发送或接收的PPP有效负载字节量。例如，如果使用64字节的默认信用比例因子，并发送128字节的PPP有效负载数据，则将消耗2个信用。在计算消费信贷时，所有信贷计算必须向上取整。在前一个示例中，如果发送了130字节的PPP有效负载数据，则会消耗3个信用。
When the peer receives a PADG packet, it adds the incremental credits to its working credit count and responds with a PPPoE Active Discovery Session-Credit Response (PADC) packet, indicating the accumulation of the credits. The FCN and BCN values must be scaled by the value established during session establishment in the Credit Scale Factor TLV or by the default 64-byte value prior to processing.
当对等方接收到PADG数据包时，它将增量信用添加到其工作信用计数中，并使用PPPoE主动发现会话信用响应（PADC）数据包进行响应，指示信用的累积。FCN和BCN值必须按照会话建立期间在Credit Scale Factor TLV中建立的值或处理前的默认64字节值进行缩放。
The PADG packet must contain a single Credits TLV, indicating the Forward Credit Notification (FCN) and the Backward Credit Notification (BCN) of the PPPoE Session.
PADG数据包必须包含一个信用TLV，指示PPPoE会话的前向信用通知（FCN）和后向信用通知（BCN）。
The Credits TLV FCN indicates the number of incremental credits being granted to the peer by the node. A value between 1 and 0xffff represents an incremental credit grant. The peer must multiply the credit units by the credit scale factor and add these credits to its accumulated transmit credit count. A value of 0x0000 represents a NULL grant, meaning that there are no additional credits being granted.
Credits TLV FCN表示节点授予对等方的增量信用数。介于1和0xffff之间的值表示增量信用授予。对等方必须将信用单位乘以信用比例因子，并将这些信用添加到其累计传输信用计数中。0x0000的值表示授予为空，这意味着不授予额外的学分。
The Credits TLV BCN indicates the remaining absolute credits that have been granted by the peer to the local node. When the local node exhausts the BCN, it must stop transmitting payload packets.
Credits TLV BCN表示对等方已向本地节点授予的剩余绝对信用。当本地节点耗尽BCN时，它必须停止传输有效负载数据包。
Once a credit has been granted, it must be honored. The largest number of incremental credits at any time is 0xffff.
信用一旦被授予，就必须兑现。任何时候增量信用的最大数量为0xffff。
The PADG packet must contain a single Sequence Number TLV. This TLV is used to carry a unique 16-bit sequence number to uniquely identify each request. The sequence number should be initialized at zero and incremented by one for each new PADG. For retransmitted PADGs, the same sequence number that was used in the previous packet transmission is repeated.
PADG数据包必须包含一个序列号TLV。该TLV用于携带唯一的16位序列号，以唯一标识每个请求。序列号应初始化为零，并为每个新PADG增加一个序列号。对于重新传输的PADG，重复先前数据包传输中使用的相同序列号。
A Discovery PADG packet with the Sequence Number and Credits TLVs is shown below:
具有序列号和信用TLV的Discovery PADG数据包如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination_mac_addr(c) | Source_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x0A |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x0E |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number TLV = 0x0108 | TLV Length = 0x02 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number | Credits TLV = 0x0106 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Length = 0x04 | FCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination_mac_addr(c) | Source_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x0A |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x0E |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number TLV = 0x0108 | TLV Length = 0x02 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number | Credits TLV = 0x0106 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Length = 0x04 | FCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The PPPoE Active Discovery Session-Credit Response (PADC) is a new packet defined in this specification. A Server or Client must send a PADC in response to a PADG. The CODE field is set to 0x0B, and the SESSION_ID must be set to the unique value generated for this PPPoE session.
PPPoE主动发现会话信用响应（PADC）是本规范中定义的新数据包。服务器或客户端必须发送PADC以响应PADG。代码字段设置为0x0B，会话ID必须设置为此PPPoE会话生成的唯一值。
The PADC packet must contain a single Credits TLV, indicating the Forward Credit Notification (FCN) and the Backward Credit Notification (BCN) of the PPPoE session.
PADC数据包必须包含单个信用TLV，指示PPPoE会话的前向信用通知（FCN）和后向信用通知（BCN）。
The Credits TLV FCN represents the absolute credits remaining that have been granted to the peer by the node. The Credits TLV BCN represents the remaining absolute credits that have been granted to the local node from the peer. The FCN and BCN values must be scaled by the value established during session establishment in the Credit Scale Factor TLV or by the default 64-byte value prior to processing.
Credits TLV FCN表示节点已授予对等方的剩余绝对信用。Credits TLV BCN表示已从对等方授予本地节点的剩余绝对信用。FCN和BCN值必须按照会话建立期间在Credit Scale Factor TLV中建立的值或处理前的默认64字节值进行缩放。
The PADC packet must contain a single Sequence Number TLV. The sequence number must be the sequence number associated with the PADG.
PADC数据包必须包含一个序列号TLV。序列号必须是与PADG关联的序列号。
A Discovery PADC packet with the Sequence Number and Credits TLV is shown below:
具有序列号和信用TLV的Discovery PADC数据包如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination_mac_addr(c) | Source_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x0B |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x0E |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number TLV = 0x0108 | TLV Length = 0x02 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number | Credits TLV = 0x0106 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Length = 0x04 | FCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination_mac_addr(c) | Source_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x0B |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x0E |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number TLV = 0x0108 | TLV Length = 0x02 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number | Credits TLV = 0x0106 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Length = 0x04 | FCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The FCN and BCN values are expressed in the respective units defined by the Credit Scale Factor TLV or the 64-byte default.
FCN和BCN值以信用比例系数TLV或64字节默认值定义的各自单位表示。
The PPPoE Active Discovery Quality (PADQ) is a new packet defined in this specification. An Server or Client may send an optional PADQ at any time to query or report link-quality metrics.
PPPoE主动发现质量（PADQ）是本规范中定义的新数据包。服务器或客户端可随时发送可选PADQ以查询或报告链接质量度量。
When transmitting PPP [1] streams over wireless links through radio modems, the quality of the RF link directly affects the throughput. The PPPoE Active Discovery Quality (PADQ) packet can be used by the radio modem to report RF link metrics. The CODE field is set to 0x0C, and the SESSION_ID must be set to the unique value generated for this PPPoE session.
当通过无线调制解调器通过无线链路传输PPP[1]流时，RF链路的质量直接影响吞吐量。无线调制解调器可以使用PPPoE主动发现质量（PADQ）数据包来报告射频链路指标。代码字段设置为0x0C，会话ID必须设置为此PPPoE会话生成的唯一值。
The PPPoE Active Discovery Quality (PADQ) packet can be used to query link metrics by setting the PADQ Metrics TLV Length to zero.
PPPoE主动发现质量（PADQ）数据包可用于通过将PADQ度量TLV长度设置为零来查询链路度量。
The PADQ must carry a single Metrics TLV. When processing the data rates, the values must be converted using the indicated data rate units. This document enhances the Metrics TLV as described below.
PADQ必须携带一个度量TLV。处理数据速率时，必须使用指示的数据速率单位转换值。本文档增强了如下所述的指标TLV。
A Discovery PADQ packet with the required Metrics TLV is shown below:
具有所需度量TLV的Discovery PADQ数据包如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x0C |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = 0x0101 | TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metrics TLV = 0x0107 | TLV Length = 0x0A |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | MD| CD|R| RLQ | Resources |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Latency (MS) | Current Datarate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Datarate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x0C |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = 0x0101 | TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metrics TLV = 0x0107 | TLV Length = 0x0A |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | MD| CD|R| RLQ | Resources |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Latency (MS) | Current Datarate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Datarate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Maximum Datarate and the Current Datarate are expressed in units determined by the MD and CD bits, respectively.
最大数据速率和当前数据速率分别以MD和CD位确定的单位表示。
A Discovery PADQ packet with a Metrics TLV Length=0 to query is shown below:
要查询的Metrics TLV Length=0的Discovery PADQ数据包如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x0C |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x08 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = 0x0101 | TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metrics TLV = 0x0107 | TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x0C |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = 0x08 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = 0x0101 | TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metrics TLV = 0x0107 | TLV Length = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The PPP Session Stage Extensions define the optional use of Credits TLV. Use of the Credits TLV in the PPP Session Stage is referred to as an in-band credit grant.
PPP会话阶段扩展定义了TLV信用的可选使用。在PPP会话阶段使用信用TLV称为带内信用授予。
The first field following the PPP Session Stage LENGTH must be checked. If the value is equal to the PPP Protocol identifier (0xc021), then normal packet (payload) processing occurs. When the field following the PPP Session Stage LENGTH is not the PPP Protocol identifier (0xc021), a TLV is assumed. In this case, the TLV length is subtracted from the overall payload length.
必须检查PPP会话阶段长度后的第一个字段。如果该值等于PPP协议标识符（0xc021），则发生正常的数据包（有效负载）处理。当PPP会话阶段长度后面的字段不是PPP协议标识符（0xc021）时，假定TLV。在这种情况下，TLV长度从总有效负载长度中减去。
A PPP LCP packet with optional Credits TLV is shown below:
具有可选信用额TLV的PPP LCP数据包如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8864 | v = 1 | t = 1 | CODE = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = (payload) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credits TLV = 0x0106 | TLV Length = 0x04 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCN | BCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PPP PROTOCOL = 0xc021 | PPP payload ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access_Concentrator_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Access_Concentrator_mac_addr(c)| Host_mac_addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host_mac_addr (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETHER_TYPE = 0x8864 | v = 1 | t = 1 | CODE = 0x00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SESSION_ID = 0x1234 | LENGTH = (payload) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credits TLV = 0x0106 | TLV Length = 0x04 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCN | BCN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PPP PROTOCOL = 0xc021 | PPP payload ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
For a given session, credit grants exchanged in the Discovery Stage, PADG-PADC, are referred to as out-of-band. Credit grants exchanged in the PPP Session Stage are referred to as in-band. Credit accounting is only applied to the packets transmitted in the PPP Session Stage.
对于给定会话，在发现阶段（PADG-PADC）中交换的信用授权称为带外。PPP会话阶段交换的信贷补助称为带内。信用核算仅适用于PPP会话阶段传输的数据包。
Out-of-band credit management is handled by periodic exchange of the PPPoE Active Discovery Session-Grant (PADG) and PPPoE Active Discovery Credit Response (PADC) packets.
带外信用管理通过定期交换PPPoE主动发现会话授权（PADG）和PPPoE主动发现信用响应（PADC）数据包来处理。
In-band credit management allows credits to be incrementally granted with each PPP Session Stage packet. These in-band incremental credit grants are not explicitly acknowledged. However, they are reflected in the in-band credit flow from the peer node. This offers the greatest credit-granting efficiency when traffic rates are high.
带内信用管理允许在每个PPP会话阶段数据包中增量授予信用。未明确确认这些带内增量信贷授予。但是，它们反映在来自对等节点的带内信用流中。这在流量较高时提供了最大的信贷授予效率。
Once agreed upon during the Discovery Stage, credit grants are required to transmit packets in the PPP Session Stage. A node must grant credits to its peer before the peer can transmit packets to the granting node.
一旦在发现阶段达成一致，就需要信用授权来在PPP会话阶段传输数据包。节点必须先向其对等方授予信用，然后该对等方才能向授予节点发送数据包。
Credits are granted incrementally in the forward direction. Locally, a node manages the credits that it has granted to a peer, as well as the credits that a peer has granted to it.
学分按正向递增方式授予。在本地，节点管理它授予对等方的信用以及对等方授予它的信用。
Grants received from a peer are added to a local running credit counter. The accumulated credits are decremented with each packet the node transmits to the peer. When the running counter reaches zero, the node must stop transmitting packets to the peer.
从对等方收到的授权将添加到本地运行的信用计数器。累积的信用随着节点发送给对等方的每个分组而递减。当运行计数器达到零时，节点必须停止向对等方发送数据包。
To manage the credits that a node has granted, the node maintains a running counter. With each PPP Session Stage packet received from the peer, the running counter is decremented. When the running counter reaches zero, no additional packets are expected. The node incrementally grants more credits to the peer to maintain packet flow. Packets received when granted credits have been exhausted are discarded.
为了管理节点已授予的积分，该节点维护一个运行计数器。当从对等方接收到每个PPP会话阶段数据包时，运行计数器递减。当运行计数器达到零时，不需要额外的数据包。节点递增地向对等方授予更多的信用，以维持数据包流。当授予的信用耗尽时接收的数据包将被丢弃。
When a node does not receive a PADC packet in response to a PADG within a specified amount of time, it should transmit a new PADG packet with zero credits, using the same sequence number and doubling the waiting period. A PADC response with the associated sequence number will indicate whether or not the previously granted credits were accumulated. If they were not, a PADG with credits and an incremented sequence number should be transmitted. This process should be repeated until granted credits are properly acknowledged or as many times as desired.
当节点在指定的时间内没有接收到响应PADG的PADC数据包时，它应该使用相同的序列号并将等待时间加倍，发送一个具有零信用的新PADG数据包。带有相关序列号的PADC响应将指示先前授予的积分是否已累积。如果没有，则应传输带有学分和递增序列号的PADG。应重复此过程，直到正确确认授予的学分，或根据需要重复多次。
When a node does not receive a PADQ metric packet in response to a query within a specified amount of time, it should resend the PADQ query packet and double the waiting period. This can be repeated as many times as desired.
当节点在指定的时间内没有收到响应查询的PADQ度量数据包时，它应该重新发送PADQ查询数据包并将等待时间延长一倍。这可以根据需要重复多次。
A node may autonomously generate PADQ metric packets. The rate of autonomously generated PADQ metric packets may need to be throttled so as not to overrun the peer.
节点可以自主地生成PADQ度量分组。可能需要限制自主生成的PADQ度量数据包的速率，以避免溢出对等方。
The sending and receiving of PPPoE Discovery packets are independent of credit counts. For example, a node must always be able to receive a PADG and send a PADC.
PPPoE发现数据包的发送和接收与信用计数无关。例如，节点必须始终能够接收PADG并发送PADC。
During normal operation, nodes may disagree about the number of credits. Operational credit mismatches would occur due to packets in transit on the wire. Much larger credit mismatches can occur if there are transmission errors. To correct these larger errors, the BCN fields of the PADG and PADC packets and in-band credit grants from a peer can be used by the receiving node to reset the credit values of its peer.
在正常操作过程中，节点可能会对信用数产生分歧。由于数据包在线路上传输，操作信用不匹配会发生。如果存在传输错误，则可能发生更大的信用错配。为了纠正这些较大的错误，接收节点可以使用PADG和PADC数据包的BCN字段以及来自对等方的带内信用授权来重置其对等方的信用值。
IANA has assigned the following PPPoE TLV Values for which this RFC serves as the reference:
IANA已分配以下PPPoE TLV值，本RFC用作参考：
TLV Value TLV Name Description Reference
----------- ------------------- ----------------- ---------
262 0x0106 Credits See the reference [RFC5578]
263 0x0107 Metrics See the reference [RFC5578]
264 0x0108 Sequence Number See the reference [RFC5578]
265 0x0109 Credit Scale Factor See the reference [RFC5578]
TLV Value TLV Name Description Reference
----------- ------------------- ----------------- ---------
262 0x0106 Credits See the reference [RFC5578]
263 0x0107 Metrics See the reference [RFC5578]
264 0x0108 Sequence Number See the reference [RFC5578]
265 0x0109 Credit Scale Factor See the reference [RFC5578]
IANA has assigned the following PPPoE Code fields for which this RFC serves as the reference:
IANA已分配以下PPPoE代码字段，该RFC用作参考：
Code PPPoE Packet Name Description Reference
-------- ---------------------- ----------------- ---------
10 0x0a PADG, Session-Grant See the reference [RFC5578]
11 0x0b PADC, Session-Credit See the reference [RFC5578]
Response
12 0x0c PADQ, Quality See the reference [RFC5578]
Code PPPoE Packet Name Description Reference
-------- ---------------------- ----------------- ---------
10 0x0a PADG, Session-Grant See the reference [RFC5578]
11 0x0b PADC, Session-Credit See the reference [RFC5578]
Response
12 0x0c PADQ, Quality See the reference [RFC5578]
This memo defines a mechanism for adding flow control to the existing PPP over Ethernet (PPPoE) sessions. These extensions are subsequent to the existing PPPoE security mechanisms as described in RFC 2516 [2]. It is required that the Service TLV and Session ID always be validated prior to processing credits.
此备忘录定义了一种机制，用于向现有的以太网PPP（PPPoE）会话添加流量控制。这些扩展是继RFC 2516[2]中描述的现有PPPoE安全机制之后的扩展。在处理积分之前，要求始终验证服务TLV和会话ID。
[1] Simpson, W., Ed., "The Point-to-Point Protocol (PPP)", STD 51, RFC 1661, July 1994.
[1] 辛普森，W.，编辑，“点对点协议（PPP）”，STD 51，RFC 1661994年7月。
[2] Mamakos, L., Lidl, K., Evarts, J., Carrel, D., Simone, D., and R. Wheeler, "A Method for Transmitting PPP Over Ethernet (PPPoE)", RFC 2516, February 1999.
[2] Mamakos，L.，Lidl，K.，Evarts，J.，Carrel，D.，Simone，D.，和R.Wheeler，“通过以太网传输PPP（PPPoE）的方法”，RFC 2516，1999年2月。
[3] An open source (GPLv2) PPPoE Client implementation of RFC 5578, PPP Over Ethernet (PPPoE) Extensions for Credit Flow and Link Metrics, http://rfc4938.sourceforge.net/.
[3] RFC 5578的开源（GPLv2）PPPoE客户端实现，用于信用流和链路度量的以太网PPPoE扩展，http://rfc4938.sourceforge.net/.
Session Credit Flow with the default 64-byte credit unit.
使用默认64字节信用单位的会话信用流。
Server Client
====================================================================
<------------PADI-------------- Initiate
------------PADO--------------> Offer
Server Client
====================================================================
<------------PADI-------------- Initiate
------------PADO--------------> Offer
<------------PADR-------------- Credits TLV:
FCN represents the initial
Client credit grant to the
Server in 64-byte units.
BCN is set to 0.
<------------PADR-------------- Credits TLV:
FCN represents the initial
Client credit grant to the
Server in 64-byte units.
BCN is set to 0.
------------PADS--------------> Credits TLV:
FCN represents the initial
Server credit grant to the
Client in 64-byte units.
BCN represents an echo of
initial Client credits.
------------PADS--------------> Credits TLV:
FCN represents the initial
Server credit grant to the
Client in 64-byte units.
BCN represents an echo of
initial Client credits.
<==============================> Data w/ optional in-band
Credits TLV
<==============================> Data w/ optional in-band
Credits TLV
<------------PADG-------------- Credits TLV: (out-of-band)
FCN represents an incremental
Client credit grant to the
Server, in 64-byte units.
BCN represents the remaining
Server credits that were granted
to the Client, in 64-byte units.
<------------PADG-------------- Credits TLV: (out-of-band)
FCN represents an incremental
Client credit grant to the
Server, in 64-byte units.
BCN represents the remaining
Server credits that were granted
to the Client, in 64-byte units.
------------PADC--------------> Credits TLV: (out-of-band)
FCN represents an incremental
Server credit grant to the
Client, in 64-byte units.
BCN represents the remaining
Client credits that were granted
to the Server, in 64-byte units.
------------PADC--------------> Credits TLV: (out-of-band)
FCN represents an incremental
Server credit grant to the
Client, in 64-byte units.
BCN represents the remaining
Client credits that were granted
to the Server, in 64-byte units.
<==============================> Data w/ optional in-band Credits
TLV
<==============================> Data w/ optional in-band Credits
TLV
<------------PADT--------------> Terminate
<------------PADT--------------> Terminate
Session Credit Flow with specific credit scale factor units for the Server and the Client.
具有服务器和客户端特定信用比例因子单位的会话信用流。
Server Client
====================================================================
<------------PADI-------------- Initiate
------------PADO--------------> Offer
Server Client
====================================================================
<------------PADI-------------- Initiate
------------PADO--------------> Offer
<------------PADR-------------- Credits TLV:
FCN represents the initial
Client credit grant to the
Server, in Credit Scale Factor
TLV units.
BCN is set to 0.
<------------PADR-------------- Credits TLV:
FCN represents the initial
Client credit grant to the
Server, in Credit Scale Factor
TLV units.
BCN is set to 0.
------------PADS--------------> Credits TLV:
FCN represents the initial
Server credit grant to the
Client, in Credit Scale Factor
TLV units.
BCN represents an echo of the
initial Client credits, in
Credit Scale Factor TLV units.
------------PADS--------------> Credits TLV:
FCN represents the initial
Server credit grant to the
Client, in Credit Scale Factor
TLV units.
BCN represents an echo of the
initial Client credits, in
Credit Scale Factor TLV units.
<==============================> Data w/ optional in-band Credits
TLV
<==============================> Data w/ optional in-band Credits
TLV
<------------PADG-------------- Credits TLV: (out-of-band)
FCN represents an incremental
Client credit grant to the Server,
in Credit Scale Factor TLV units.
BCN represents the remaining
Server credits that were granted
to the Client, in Credit Scale
Factor TLV units.
<------------PADG-------------- Credits TLV: (out-of-band)
FCN represents an incremental
Client credit grant to the Server,
in Credit Scale Factor TLV units.
BCN represents the remaining
Server credits that were granted
to the Client, in Credit Scale
Factor TLV units.
------------PADC--------------> Credits TLV: (out-of-band)
FCN represents an incremental
Server credit grant to the Client,
in Credit Scale Factor TLV units.
BCN represents the remaining
Client credits that were granted
to the Server, in Credit Scale
Factor TLV units.
------------PADC--------------> Credits TLV: (out-of-band)
FCN represents an incremental
Server credit grant to the Client,
in Credit Scale Factor TLV units.
BCN represents the remaining
Client credits that were granted
to the Server, in Credit Scale
Factor TLV units.
<==============================> Data w/ optional inband Credits
TLV
<==============================> Data w/ optional inband Credits
TLV
<------------PADT--------------> Terminate
<------------PADT--------------> Terminate
Authors' Addresses
作者地址
Bo Berry, Editor Cisco 170 West Tasman Drive San Jose, CA 95134 EMail: bberry@cisco.com
Bo Berry，编辑Cisco 170 West Tasman Drive San Jose，CA 95134电子邮件：bberry@cisco.com
Stan Ratliff Cisco 170 West Tasman Drive San Jose, CA 95134 EMail: sratliff@cisco.com
Stan Ratliff Cisco 170西塔斯曼大道圣何塞，加利福尼亚州95134电子邮件：sratliff@cisco.com
Ed Paradise Cisco 170 West Tasman Drive San Jose, CA 95134 EMail: pdice@cisco.com
Ed Paradise Cisco 170西塔斯曼大道圣何塞，加利福尼亚州95134电子邮件：pdice@cisco.com
Tim Kaiser Harris Corporation Government Communications System Division Mail Stop 25-11F P.O. Box 37 Melbourne, FL 32902-0037 EMail: timothy.kaiser@harris.com
Tim Kaiser Harris公司政府通信系统部门邮箱地址：佛罗里达州墨尔本37号邮政信箱25-11楼32902-0037电子邮件：timothy。kaiser@harris.com
Michael D Adams 640 N 2200 W MS F1J12 Salt Lake City, Utah 84116 EMail: Michael.D.Adams@L-3com.com
Michael D Adams 640 N 2200 W MS F1J12犹他州盐湖城84116电子邮件：Michael D。Adams@L-3com.com