Internet Engineering Task Force (IETF) H. Long
Request for Comments: 8625 M. Ye, Ed.
Category: Standards Track Huawei Technologies Co., Ltd.
ISSN: 2070-1721 G. Mirsky, Ed.
ZTE
A. D'Alessandro
Telecom Italia S.p.A
H. Shah
Ciena
August 2019
Internet Engineering Task Force (IETF) H. Long
Request for Comments: 8625 M. Ye, Ed.
Category: Standards Track Huawei Technologies Co., Ltd.
ISSN: 2070-1721 G. Mirsky, Ed.
ZTE
A. D'Alessandro
Telecom Italia S.p.A
H. Shah
Ciena
August 2019
Ethernet Traffic Parameters with Availability Information
具有可用性信息的以太网流量参数
Abstract
摘要
A packet-switching network may contain links with variable bandwidths (e.g., copper and radio). The bandwidth of such links is sensitive to the external environment (e.g., climate). Availability is typically used to describe these links when doing network planning. This document introduces an optional Bandwidth Availability TLV in RSVP-TE signaling. This extension can be used to set up a GMPLS Label Switched Path (LSP) in conjunction with the Ethernet SENDER_TSPEC object.
分组交换网络可以包含具有可变带宽的链路（例如，铜缆和无线电）。此类链路的带宽对外部环境（如气候）敏感。在进行网络规划时，可用性通常用于描述这些链接。本文档介绍RSVP-TE信令中的可选带宽可用性TLV。此扩展可用于与Ethernet SENDER_TSPEC对象一起设置GMPLS标签交换路径（LSP）。
Status of This Memo
关于下段备忘
This is an Internet Standards Track document.
这是一份互联网标准跟踪文件。
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.
本文件是互联网工程任务组（IETF）的产品。它代表了IETF社区的共识。它已经接受了公众审查，并已被互联网工程指导小组（IESG）批准出版。有关互联网标准的更多信息，请参见RFC 7841第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8625.
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https://www.rfc-editor.org/info/rfc8625.
Copyright Notice
版权公告
Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved.
版权（c）2019 IETF信托基金和被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 (https://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. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(https://trustee.ietf.org/license-info)自本文件出版之日起生效。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。从本文件中提取的代码组件必须包括信托法律条款第4.e节中所述的简化BSD许可证文本，并提供简化BSD许可证中所述的无担保。
Table of Contents
目录
1. Introduction ....................................................3
1.1. Conventions Used in This Document ..........................4
2. Overview ........................................................4
3. Extension to RSVP-TE Signaling ..................................5
3.1. Bandwidth Availability TLV .................................5
3.2. Signaling Process ..........................................6
4. Security Considerations .........................................7
5. IANA Considerations .............................................8
6. References ......................................................8
6.1. Normative References .......................................8
6.2. Informative References .....................................9
Appendix A. Bandwidth Availability Example .......................11
Acknowledgments ...................................................13
Authors' Addresses ................................................13
1. Introduction ....................................................3
1.1. Conventions Used in This Document ..........................4
2. Overview ........................................................4
3. Extension to RSVP-TE Signaling ..................................5
3.1. Bandwidth Availability TLV .................................5
3.2. Signaling Process ..........................................6
4. Security Considerations .........................................7
5. IANA Considerations .............................................8
6. References ......................................................8
6.1. Normative References .......................................8
6.2. Informative References .....................................9
Appendix A. Bandwidth Availability Example .......................11
Acknowledgments ...................................................13
Authors' Addresses ................................................13
The RSVP-TE specification [RFC3209] and GMPLS extensions [RFC3473] specify the signaling message, including the bandwidth request for setting up an LSP in a packet-switching network.
RSVP-TE规范[RFC3209]和GMPLS扩展[RFC3473]规定了信令消息，包括在分组交换网络中设置LSP的带宽请求。
Some data communication technologies allow a seamless change of the maximum physical bandwidth through a set of known discrete values. The parameter availability [G.827] [F.1703] [P.530] is often used to describe the link capacity during network planning. The availability is based on a time scale, which is a proportion of the operating time that the requested bandwidth is ensured. A more detailed example of bandwidth availability can be found in Appendix A. Assigning different bandwidth availability classes to different types of services over links with variable discrete bandwidth provides for a more efficient planning of link capacity. To set up an LSP across these links, bandwidth availability information is required for the nodes to verify bandwidth satisfaction and make a bandwidth reservation. The bandwidth availability information should be inherited from the bandwidth availability requirements of the services expected to be carried on the LSP. For example, voice service usually needs 99.999% bandwidth availability, while non-real-time services may adequately perform at 99.99% or 99.9% bandwidth availability. Since different service types may need different availability guarantees, multiple <availability, bandwidth> pairs may be required when signaling.
一些数据通信技术允许通过一组已知的离散值无缝地改变最大物理带宽。参数可用性[G.827][F.1703][P.530]通常用于描述网络规划期间的链路容量。可用性基于时间尺度，时间尺度是确保所请求带宽的操作时间的一部分。关于带宽可用性的更详细示例，请参见附录A。在具有可变离散带宽的链路上为不同类型的服务分配不同的带宽可用性等级，可以更有效地规划链路容量。要跨这些链路设置LSP，节点需要带宽可用性信息来验证带宽满足度并进行带宽预留。带宽可用性信息应继承自预期在LSP上承载的服务的带宽可用性要求。例如，语音服务通常需要99.999%的带宽可用性，而非实时服务可能需要99.99%或99.9%的带宽可用性。由于不同的服务类型可能需要不同的可用性保证，因此在发送信号时可能需要多个<可用性，带宽>对。
If the bandwidth availability requirement is not specified in the signaling message, the bandwidth will likely be reserved as the highest bandwidth availability. Suppose, for example, the bandwidth with 99.999% availability of a link is 100 Mbps, and the bandwidth with 99.99% availability is 200 Mbps. When a video application makes a request for 120 Mbps without a bandwidth availability requirement, the system will consider the request as 120 Mbps with 99.999% bandwidth availability, while the available bandwidth with 99.999% bandwidth availability is only 100 Mbps. Therefore, the LSP path cannot be set up. However, the video application doesn't need 99.999% bandwidth availability; 99.99% bandwidth availability is enough. In this case, the LSP could be set up if the bandwidth availability is also specified in the signaling message.
如果在信令消息中未指定带宽可用性要求，则带宽可能会保留为最高带宽可用性。例如，假设链路可用性为99.999%的带宽为100 Mbps，可用性为99.99%的带宽为200 Mbps。当视频应用在没有带宽可用性要求的情况下请求120 Mbps时，系统将考虑该请求为具有120带宽可用性的120 Mbps，而可用带宽为99.999%的可用带宽仅为100 Mbps。因此，无法设置LSP路径。但是，视频应用程序不需要99.999%的带宽可用性；99.99%的带宽可用性就足够了。在这种情况下，如果在信令消息中也指定了带宽可用性，则可以设置LSP。
To fulfill an LSP setup by signaling in these scenarios, this document specifies a Bandwidth Availability TLV. The Bandwidth Availability TLV can be applicable to any kind of physical link with variable discrete bandwidth, such as microwave or DSL. Multiple Bandwidth Availability TLVs, together with multiple Ethernet
为了在这些场景中通过信令实现LSP设置，本文档指定了带宽可用性TLV。带宽可用性TLV可适用于具有可变离散带宽的任何类型的物理链路，例如微波或DSL。多带宽可用性TLV，以及多个以太网
Bandwidth Profile TLVs, can be carried by the Ethernet SENDER_TSPEC object [RFC6003]. Since the Ethernet FLOWSPEC object has the same format as the Ethernet SENDER_TSPEC object [RFC6003], the Bandwidth Availability TLV can also be carried by the Ethernet FLOWSPEC object.
以太网发送器\u TSPEC对象[RFC6003]可以携带带宽配置文件TLV。由于Ethernet FLOWSPEC对象与Ethernet SENDER_TSPEC对象[RFC6003]具有相同的格式，因此Ethernet FLOWSPEC对象也可以携带带宽可用性TLV。
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“建议”、“不建议”、“可”和“可选”在所有大写字母出现时（如图所示）应按照BCP 14[RFC2119][RFC8174]所述进行解释。
The following acronyms are used in this document:
本文件中使用了以下首字母缩略词：
RSVP-TE Resource Reservation Protocol - Traffic Engineering
RSVP-TE资源预留协议-流量工程
LSP Label Switched Path
标签交换路径
SNR Signal-to-Noise Ratio
信噪比
TLV Type-Length-Value
TLV类型长度值
LSA Link State Advertisement
链路状态广告
QAM Quadrature Amplitude Modulation
正交幅度调制
QPSK Quadrature Phase Shift Keying
QPSK正交相移键控
A tunnel in a packet-switching network may span one or more links in a network. To set up an LSP, a node may collect link information that is advertised in a routing message (e.g., an OSPF TE LSA message) by network nodes to obtain network topology information, and it can then calculate an LSP route based on the network topology. The calculated LSP route is signaled using a PATH/RESV message to set up the LSP.
分组交换网络中的隧道可以跨越网络中的一个或多个链路。为了建立LSP，节点可以收集由网络节点在路由消息（例如，OSPF TE LSA消息）中通告的链路信息以获得网络拓扑信息，然后它可以基于网络拓扑计算LSP路由。使用PATH/RESV消息向计算的LSP路由发送信号，以设置LSP。
If a network contains one or more links with variable discrete bandwidths, a <bandwidth, availability> requirement list should be specified for an LSP at setup. Each <bandwidth, availability> pair in the list means the listed bandwidth with specified availability is required. The list can be derived from the results of service planning for the LSP.
如果网络包含一个或多个具有可变离散带宽的链路，则应在设置时为LSP指定<带宽，可用性>要求列表。列表中的每个<带宽，可用性>对表示需要具有指定可用性的所列带宽。该列表可以从LSP的服务规划结果中导出。
A node that has link(s) with variable discrete bandwidth attached should contain a <bandwidth, availability> information list in its OSPF TE LSA messages. The list provides the mapping between the link nominal bandwidth and its availability level. This information can then be used for path calculation by the node(s). The routing extension for availability can be found in [RFC8330].
连接有可变离散带宽的链路的节点应在其OSPF TE LSA消息中包含<带宽，可用性>信息列表。该列表提供链路标称带宽与其可用性级别之间的映射。然后，该信息可用于节点的路径计算。可用性路由扩展可在[RFC8330]中找到。
When a node initiates a PATH/RESV signaling to set up an LSP, the PATH message should carry the <bandwidth, availability> requirement list as a bandwidth request. Intermediate node(s) will allocate the bandwidth resources for each availability requirement from the remaining bandwidth with the corresponding availability. An error message may be returned if any <bandwidth, availability> request cannot be satisfied.
当节点启动PATH/RESV信令以建立LSP时，PATH消息应携带<bandwidth，availability>需求列表作为带宽请求。中间节点将从具有相应可用性的剩余带宽中为每个可用性需求分配带宽资源。如果无法满足任何<带宽，可用性>请求，可能会返回错误消息。
A Bandwidth Availability TLV is defined as a TLV of the Ethernet SENDER_TSPEC object [RFC6003] in this document. The Ethernet SENDER_TSPEC object MAY include more than one Bandwidth Availability TLV. The Bandwidth Availability TLV has the following format:
带宽可用性TLV在本文档中定义为以太网发送器\u TSPEC对象[RFC6003]的TLV。Ethernet SENDER_TSPEC对象可以包括多个带宽可用性TLV。带宽可用性TLV具有以下格式：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Index | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Availability |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Index | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Availability |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Bandwidth Availability TLV
图1：带宽可用性TLV
Type (2 octets): 4
类型（2个八位组）：4
Length (2 octets): 0x0C. Indicates the length in bytes of the whole TLV, including the Type and Length fields. In this case, the length is 12 bytes.
长度（2个八位字节）：0x0C。指示整个TLV的长度（以字节为单位），包括类型和长度字段。在本例中，长度为12字节。
Index (1 octet): When the Bandwidth Availability TLV is included, the Ethernet Bandwidth Profile TLV MUST also be included. If there are multiple bandwidth requirements present (in multiple Ethernet Bandwidth Profile TLVs) and they have different availability requirements, multiple Bandwidth Availability TLVs MUST be carried. In such a case, the Bandwidth Availability TLV has a one-to-one
索引（1个八位字节）：包括带宽可用性TLV时，还必须包括以太网带宽配置文件TLV。如果存在多个带宽需求（在多个以太网带宽配置文件TLV中），并且它们具有不同的可用性需求，则必须携带多个带宽可用性TLV。在这种情况下，带宽可用性TLV具有一对一的特性
correspondence with the Ethernet Bandwidth Profile TLV as both have the same value in the Index field. If all the bandwidth requirements in the Ethernet Bandwidth Profile TLV have the same availability requirement, one Bandwidth Availability TLV SHOULD be carried. In this case, the Index field is set to 0.
与以太网带宽配置文件TLV的对应关系，因为两者在索引字段中具有相同的值。如果以太网带宽配置文件TLV中的所有带宽要求具有相同的可用性要求，则应携带一个带宽可用性TLV。在这种情况下，索引字段设置为0。
Reserved (3 octets): These bits SHOULD be set to zero when sent and MUST be ignored when received.
保留（3个八位字节）：这些位在发送时应设置为零，在接收时必须忽略。
Availability (4 octets): A 32-bit floating-point number in binary interchange format [IEEE754] describes the decimal value of the availability requirement for this bandwidth request. The value MUST be less than 1 and is usually expressed as one of the following values: 0.99, 0.999, 0.9999, or 0.99999. The IEEE floating-point number is used here to align with [RFC8330]. When representing values higher than 0.999999, the floating-point number starts to introduce errors to intended precision. However, in reality, 0.99999 is normally considered the highest availability value (which results in 5 minutes of outage in a year) in a telecom network. Therefore, the use of a floating-point number for availability is acceptable.
可用性（4个八位字节）：二进制交换格式的32位浮点数字[IEEE754]描述此带宽请求的可用性要求的十进制值。该值必须小于1，并且通常表示为以下值之一：0.99、0.999、0.9999或0.99999。此处使用IEEE浮点数与[RFC8330]对齐。当表示大于0.999999的值时，浮点数开始引入预期精度的错误。然而，在现实中，0.99999通常被认为是电信网络中的最高可用性值（导致一年中断5分钟）。因此，使用浮点数表示可用性是可以接受的。
The source node initiates a PATH message, which may carry a number of bandwidth requests, including one or more Ethernet Bandwidth Profile TLVs and one or more Bandwidth Availability TLVs. Each Ethernet Bandwidth Profile TLV corresponds to an availability parameter in the associated Bandwidth Availability TLV.
源节点发起路径消息，该消息可承载多个带宽请求，包括一个或多个以太网带宽配置文件tlv和一个或多个带宽可用性tlv。每个以太网带宽配置文件TLV对应于相关带宽可用性TLV中的可用性参数。
When the intermediate and destination nodes receive the PATH message, the nodes compare the requested bandwidth under each availability level in the SENDER_TSPEC objects, with the remaining link bandwidth resources under a corresponding availability level on a local link, to check if they can meet the bandwidth requirements.
当中间节点和目标节点接收到PATH消息时，节点将发送方_TSPEC对象中每个可用性级别下的请求带宽与本地链路上相应可用性级别下的剩余链路带宽资源进行比较，以检查它们是否能满足带宽要求。
o When all <bandwidth, availability> requirement requests can be satisfied (that is, the requested bandwidth under each availability parameter is smaller than or equal to the remaining bandwidth under the corresponding availability parameter on its local link), the node SHOULD reserve the bandwidth resources from each remaining sub-bandwidth portion on its local link to set up this LSP. Optionally, a higher availability bandwidth can be allocated to a lower availability request when the lower availability bandwidth cannot satisfy the request.
o 当满足所有<带宽，可用性>需求请求时（即每个可用性参数下的请求带宽小于或等于其本地链路上相应可用性参数下的剩余带宽），节点应保留其本地链路上每个剩余子带宽部分的带宽资源，以设置此LSP。可选地，当较低的可用性带宽不能满足请求时，可以将较高的可用性带宽分配给较低的可用性请求。
o When at least one <bandwidth, availability> requirement request cannot be satisfied, the node SHOULD generate a PathErr message with the error code "Admission Control Error" and the error value "Requested Bandwidth Unavailable" (see [RFC2205]).
o 当至少一个<带宽，可用性>需求请求无法满足时，节点应生成一条PathErr消息，错误代码为“准入控制错误”，错误值为“请求的带宽不可用”（请参阅[RFC2205]）。
When two LSPs request bandwidth with the same availability requirement, the contention MUST be resolved by comparing the node IDs, where the LSP with the higher node ID is assigned the reservation. This is consistent with the general contention resolution mechanism provided in Section 4.2 of [RFC3471].
当两个LSP请求具有相同可用性要求的带宽时，必须通过比较节点ID来解决争用，其中具有较高节点ID的LSP被分配保留。这与[RFC3471]第4.2节中提供的一般争用解决机制一致。
When a node does not support the Bandwidth Availability TLV, the node should send a PathErr message with error code "Unknown Attributes TLV", as specified in [RFC5420]. An LSP could also be set up in this case if there's enough bandwidth (note that the availability level of the reserved bandwidth is unknown). When a node receives Bandwidth Availability TLVs with a mix of zero and non-zero indexes, the message MUST be ignored and MUST NOT be propagated. When a node receives Bandwidth Availability TLVs (non-zero index) with no matching index value among the Ethernet Bandwidth Profile TLVs, the message MUST be ignored and MUST NOT be propagated. When a node receives several <bandwidth, availability> pairs, but there are extra Ethernet Bandwidth Profile TLVs that do not match the index of any Bandwidth Availability TLV, the extra Ethernet Bandwidth Profile TLVs MUST be ignored and MUST NOT be propagated.
当节点不支持带宽可用性TLV时，该节点应发送一条PathErr消息，错误代码为[RFC5420]中指定的“未知属性TLV”。如果有足够的带宽，也可以在这种情况下设置LSP（请注意，保留带宽的可用性级别未知）。当一个节点接收到带宽可用性TLV时，混合使用零和非零索引，该消息必须被忽略，并且不得传播。当节点接收到带宽可用性TLV（非零索引）且以太网带宽配置文件TLV之间没有匹配的索引值时，必须忽略该消息，并且不得传播该消息。当一个节点接收到多个<带宽，可用性>对，但存在与任何带宽可用性TLV的索引不匹配的额外以太网带宽配置文件TLV时，必须忽略该额外以太网带宽配置文件TLV，并且不得传播。
This document defines a Bandwidth Availability TLV in RSVP-TE signaling used in GMPLS networks. [RFC3945] notes that authentication in GMPLS systems may use the authentication mechanisms of the component protocols. [RFC5920] provides an overview of security vulnerabilities and protection mechanisms for the GMPLS control plane. In particular, Section 7.1.2 of [RFC5920] discusses the control-plane protection with RSVP-TE by using general RSVP security tools, limiting the impact of an attack on control-plane resources, and using authentication for RSVP messages. Moreover, the GMPLS network is often considered to be a closed network such that insertion, modification, or inspection of packets by an outside party is not possible.
本文件定义了GMPLS网络中使用的RSVP-TE信令中的带宽可用性TLV。[RFC3945]注意，GMPLS系统中的认证可能使用组件协议的认证机制。[RFC5920]概述了GMPLS控制平面的安全漏洞和保护机制。具体而言，[RFC5920]第7.1.2节讨论了通过使用通用RSVP安全工具、限制攻击对控制平面资源的影响以及对RSVP消息使用身份验证，使用RSVP-TE保护控制平面。此外，GMPLS网络通常被认为是封闭的网络，使得外部方不可能插入、修改或检查分组。
IANA maintains a registry of GMPLS parameters called the "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Parameters" registry. This registry includes the "Ethernet Sender TSpec TLVs/ Ethernet Flowspec TLVs" subregistry that contains the TLV type values for TLVs carried in the Ethernet SENDER_TSPEC object. This subregistry has been updated to include the Bandwidth Availability TLV:
IANA维护一个名为“通用多协议标签交换（GMPLS）信令参数”注册表的GMPLS参数注册表。此注册表包括“Ethernet Sender TSpec TLV/Ethernet Flowspec TLV”子注册表，该子注册表包含Ethernet Sender_TSpec对象中携带的TLV的TLV类型值。该子区域已更新，包括带宽可用性TLV：
Type Description Reference
---- ---------------------- ---------
4 Bandwidth Availability RFC 8625
Type Description Reference
---- ---------------------- ---------
4 Bandwidth Availability RFC 8625
[IEEE754] IEEE, "IEEE Standard for Floating-Point Arithmetic", IEEE 754, DOI 10.1109/IEEESTD.2008.4610935.
[IEEE754]IEEE，“IEEE浮点运算标准”，IEEE 754，DOI 10.1109/IEEESTD.2008.4610935。
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>.
[RFC2119]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，DOI 10.17487/RFC2119，1997年3月<https://www.rfc-editor.org/info/rfc2119>.
[RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, DOI 10.17487/RFC2205, September 1997, <https://www.rfc-editor.org/info/rfc2205>.
[RFC2205]Braden，R.，Ed.，Zhang，L.，Berson，S.，Herzog，S.，和S.Jamin，“资源保留协议（RSVP）——版本1功能规范”，RFC 2205，DOI 10.17487/RFC2205，1997年9月<https://www.rfc-editor.org/info/rfc2205>.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, <https://www.rfc-editor.org/info/rfc3209>.
[RFC3209]Awduche，D.，Berger，L.，Gan，D.，Li，T.，Srinivasan，V.，和G.Swallow，“RSVP-TE：LSP隧道RSVP的扩展”，RFC 3209，DOI 10.17487/RFC3209，2001年12月<https://www.rfc-editor.org/info/rfc3209>.
[RFC3471] Berger, L., Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description", RFC 3471, DOI 10.17487/RFC3471, January 2003, <https://www.rfc-editor.org/info/rfc3471>.
[RFC3471]Berger，L.，Ed.“通用多协议标签交换（GMPLS）信令功能描述”，RFC 3471，DOI 10.17487/RFC3471，2003年1月<https://www.rfc-editor.org/info/rfc3471>.
[RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC 3473, DOI 10.17487/RFC3473, January 2003, <https://www.rfc-editor.org/info/rfc3473>.
[RFC3473]Berger，L.，Ed.“通用多协议标签交换（GMPLS）信令资源预留协议流量工程（RSVP-TE）扩展”，RFC 3473，DOI 10.17487/RFC3473，2003年1月<https://www.rfc-editor.org/info/rfc3473>.
[RFC5420] Farrel, A., Ed., Papadimitriou, D., Vasseur, JP., and A. Ayyangarps, "Encoding of Attributes for MPLS LSP Establishment Using Resource Reservation Protocol Traffic Engineering (RSVP-TE)", RFC 5420, DOI 10.17487/RFC5420, February 2009, <https://www.rfc-editor.org/info/rfc5420>.
[RFC5420]Farrel，A.，Ed.，Papadimitriou，D.，Vasseur，JP.，和A.Ayangarps，“使用资源预留协议流量工程（RSVP-TE）对MPLS LSP建立的属性进行编码”，RFC 5420，DOI 10.17487/RFC5420，2009年2月<https://www.rfc-editor.org/info/rfc5420>.
[RFC6003] Papadimitriou, D., "Ethernet Traffic Parameters", RFC 6003, DOI 10.17487/RFC6003, October 2010, <https://www.rfc-editor.org/info/rfc6003>.
[RFC6003]Papadimitriou，D.，“以太网流量参数”，RFC 6003，DOI 10.17487/RFC6003，2010年10月<https://www.rfc-editor.org/info/rfc6003>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8174]Leiba，B.，“RFC 2119关键词中大写与小写的歧义”，BCP 14，RFC 8174，DOI 10.17487/RFC8174，2017年5月<https://www.rfc-editor.org/info/rfc8174>.
[EN-302-217] ETSI, "Fixed Radio Systems; Characteristics and requirements for point-to-point equipment and antennas; Part 1: Overview and system-independent common characteristics", ETSI EN 302 217-1, Version 3.1.1, May 2017.
[EN-302-217]ETSI，“固定无线电系统；点对点设备和天线的特性和要求；第1部分：概述和系统独立通用特性”，ETSI EN 302 217-1，版本3.1.1，2017年5月。
[F.1703] ITU-R, "Availability objectives for real digital fixed wireless links used in 27 500 km hypothetical reference paths and connections", ITU-R Recommendation F.1703-0, January 2005, <https://www.itu.int/rec/R-REC-F.1703/en>.
[F.1703]ITU-R，“在27 500 km假设参考路径和连接中使用的真实数字固定无线链路的可用性目标”，ITU-R建议F.1703-0，2005年1月<https://www.itu.int/rec/R-REC-F.1703/en>.
[G.827] ITU-T, "Availability performance parameters and objectives for end-to-end international constant bit-rate digital paths", ITU-T Recommendation G.827, September 2003, <https://www.itu.int/rec/T-REC-G.827/en>.
[G.827]ITU-T，“端到端国际恒定比特率数字路径的可用性性能参数和目标”，ITU-T建议G.827，2003年9月<https://www.itu.int/rec/T-REC-G.827/en>.
[P.530] ITU-R, "Propagation data and prediction methods required for the design of terrestrial line-of-sight systems", ITU-R Recommendation P.530-17, December 2017, <https://www.itu.int/rec/R-REC-P.530/en>.
[P.530]ITU-R，“地面视线系统设计所需的传播数据和预测方法”，ITU-R建议P.530-172017年12月<https://www.itu.int/rec/R-REC-P.530/en>.
[RFC3945] Mannie, E., Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Architecture", RFC 3945, DOI 10.17487/RFC3945, October 2004, <https://www.rfc-editor.org/info/rfc3945>.
[RFC3945]Mannie，E.，Ed.“通用多协议标签交换（GMPLS）体系结构”，RFC 3945，DOI 10.17487/RFC3945，2004年10月<https://www.rfc-editor.org/info/rfc3945>.
[RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010, <https://www.rfc-editor.org/info/rfc5920>.
[RFC5920]方，L.，编辑，“MPLS和GMPLS网络的安全框架”，RFC 5920，DOI 10.17487/RFC5920，2010年7月<https://www.rfc-editor.org/info/rfc5920>.
[RFC8330] Long, H., Ye, M., Mirsky, G., D'Alessandro, A., and H. Shah, "OSPF Traffic Engineering (OSPF-TE) Link Availability Extension for Links with Variable Discrete Bandwidth", RFC 8330, DOI 10.17487/RFC8330, February 2018, <https://www.rfc-editor.org/info/rfc8330>.
[RFC8330]Long，H.，Ye，M.，Mirsky，G.，D'Alessandro，A.，和H.Shah，“可变离散带宽链路的OSPF流量工程（OSPF-TE）链路可用性扩展”，RFC 8330，DOI 10.17487/RFC8330，2018年2月<https://www.rfc-editor.org/info/rfc8330>.
In mobile backhaul networks, microwave links are very popular for providing connections of last hops. To maintain link connectivity in heavy rain conditions, the microwave link may lower the modulation level since moving to a lower modulation level provides for a lower SNR requirement. This is called "adaptive modulation" technology [EN-302-217]. However, a lower modulation level also means a lower link bandwidth. When a link bandwidth is reduced because of modulation downshifting, high-priority traffic can be maintained, while lower-priority traffic is dropped. Similarly, copper links may change their link bandwidth due to external interference.
在移动回程网络中，微波链路非常流行，用于提供最后一跳的连接。为了在大雨条件下保持链路连接，微波链路可以降低调制电平，因为移动到较低的调制电平提供较低的SNR要求。这被称为“自适应调制”技术[EN-302-217]。然而，较低的调制电平也意味着较低的链路带宽。当由于调制降档而降低链路带宽时，可以维持高优先级通信量，而丢弃低优先级通信量。类似地，铜链路可能由于外部干扰而改变其链路带宽。
Presume that a link has three discrete bandwidth levels:
假设链路有三个离散的带宽级别：
o The link bandwidth under modulation level 1 (e.g., QPSK) is 100 Mbps.
o 调制级别1（例如，QPSK）下的链路带宽为100mbps。
o The link bandwidth under modulation level 2 (e.g., 16QAM) is 200 Mbps.
o 调制级别2（例如，16QAM）下的链路带宽为200mbps。
o The link bandwidth under modulation level 3 (e.g., 256QAM) is 400 Mbps.
o 调制级别3（例如256QAM）下的链路带宽为400 Mbps。
On a sunny day, modulation level 3 can be used to achieve a 400 Mbps link bandwidth.
在晴朗的日子里，调制级别3可用于实现400 Mbps链路带宽。
Light rain with a X mm/h rate triggers the system to change the modulation level from level 3 to level 2, with the bandwidth changing from 400 Mbps to 200 Mbps. The probability of X mm/h rain in the local area is 52 minutes in a year. Then the dropped 200 Mbps bandwidth has 99.99% availability.
速率为X mm/h的小雨触发系统将调制级别从3级更改为2级，带宽从400 Mbps更改为200 Mbps。当地每年降雨的概率为52分钟。然后，丢弃的200 Mbps带宽具有99.99%的可用性。
Heavy rain with a Y(Y>X) mm/h rate triggers the system to change the modulation level from level 2 to level 1, with the bandwidth changing from 200 Mbps to 100 Mbps. The probability of Y mm/h rain in the local area is 26 minutes in a year. Then the dropped 100 Mbps bandwidth has 99.995% availability.
Y（Y>X）mm/h速率的大雨触发系统将调制级别从2级更改为1级，带宽从200 Mbps更改为100 Mbps。当地一年中Y mm/h降雨的概率为26分钟。然后，下降的100 Mbps带宽具有99.995%的可用性。
For the 100 Mbps bandwidth of modulation level 1, only extreme weather conditions can cause the whole system to be unavailable, which only happens for 5 minutes in a year. So the 100 Mbps bandwidth of the modulation level 1 owns the availability of 99.999%.
对于调制级别1的100 Mbps带宽，只有极端天气条件才能导致整个系统不可用，一年中仅发生5分钟。因此，调制级别1的100 Mbps带宽拥有99.999%的可用性。
There are discrete buckets per availability level. Under the worst weather conditions, there's only 100 Mbps capacity, which is 99.999% available. It's treated effectively as "always available" since better availability is not possible. If the weather is bad but not
每个可用性级别都有离散的存储桶。在最恶劣的天气条件下，只有100 Mbps的容量，即99.999%的可用容量。它被有效地视为“始终可用”，因为更好的可用性是不可能的。如果天气不好，但天气不好
the worst possible conditions, modulation level 2 can be used, which gets an additional 100 Mbps bandwidth (i.e., 200 Mbps total). Therefore, 100 Mbps is in the 99.999% bucket, and 100 Mbps is in the 99.995% bucket. In clear weather, modulation level 3 can be used to get 400 Mbps total, but that's only 200 Mbps more than at modulation level 2, so the 99.99% bucket has that "extra" 200 Mbps, and the other two buckets still have 100 Mbps each.
在可能的最坏情况下，可以使用调制级别2，它可以获得额外的100 Mbps带宽（即总共200 Mbps）。因此，100 Mbps在99.999%的存储桶中，100 Mbps在99.995%的存储桶中。在晴朗的天气下，调制级别3可用于获得400 Mbps的总速率，但这仅比调制级别2多200 Mbps，因此99.99%的存储桶具有“额外”200 Mbps，而其他两个存储桶仍各自具有100 Mbps。
Therefore, the maximum bandwidth is 400 Mbps. The sub-bandwidth and its availability according to the weather conditions are shown as follows:
因此，最大带宽为400 Mbps。根据天气条件，子带宽及其可用性如下所示：
Sub-bandwidth (Mbps) Availability
------------------ ------------
Sub-bandwidth (Mbps) Availability
------------------ ------------
200 99.99%
200 99.99%
100 99.995%
100 99.995%
100 99.999%
100 99.999%
Acknowledgments
致谢
The authors would like to thank Deborah Brungard, Khuzema Pithewan, Lou Berger, Yuji Tochio, Dieter Beller, and Autumn Liu for their comments on and contributions to the document.
作者感谢Deborah Brungard、Khuzema Pithewan、Lou Berger、Yuji Tochio、Dieter Beller和秋刘对本文件的评论和贡献。
Authors' Addresses
作者地址
Hao Long Huawei Technologies Co., Ltd. No.1899, Xiyuan Avenue, Hi-tech Western District Chengdu 611731 China
中国成都高新西区西园大道1899号昊龙华为技术有限公司611731
Phone: +86-18615778750
Email: longhao@huawei.com
Phone: +86-18615778750
Email: longhao@huawei.com
Min Ye (editor) Huawei Technologies Co., Ltd. No.1899, Xiyuan Avenue, Hi-tech Western District Chengdu 611731 China
民业（编辑）华为技术有限公司中国成都高新西区西苑大道1899号611731
Email: amy.yemin@huawei.com
Email: amy.yemin@huawei.com
Greg Mirsky (editor) ZTE
格雷格·米尔斯基（编辑）中兴通讯
Email: gregimirsky@gmail.com
Email: gregimirsky@gmail.com
Alessandro D'Alessandro Telecom Italia S.p.A
亚历山德罗意大利电信公司
Email: alessandro.dalessandro@telecomitalia.it
Email: alessandro.dalessandro@telecomitalia.it
Himanshu Shah Ciena Corp. 3939 North First Street San Jose, CA 95134 United States of America
Himanshu Shah Ciena Corp.美国加利福尼亚州圣何塞北第一街3939号，邮编95134
Email: hshah@ciena.com
Email: hshah@ciena.com