Internet Engineering Task Force (IETF) M. Tuexen
Request for Comments: 7496 Muenster Univ. of Appl. Sciences
Category: Standards Track R. Seggelmann
ISSN: 2070-1721 Metafinanz Informationssysteme GmbH
R. Stewart
Netflix, Inc.
S. Loreto
Ericsson
April 2015
Internet Engineering Task Force (IETF) M. Tuexen
Request for Comments: 7496 Muenster Univ. of Appl. Sciences
Category: Standards Track R. Seggelmann
ISSN: 2070-1721 Metafinanz Informationssysteme GmbH
R. Stewart
Netflix, Inc.
S. Loreto
Ericsson
April 2015
Additional Policies for the Partially Reliable Stream Control Transmission Protocol Extension
部分可靠流控制传输协议扩展的附加策略
Abstract
摘要
This document defines two additional policies for the Partially Reliable Stream Control Transmission Protocol (PR-SCTP) extension. These policies allow limitation of the number of retransmissions and prioritization of user messages for more efficient usage of the send buffer.
本文档为部分可靠流控制传输协议（PR-SCTP）扩展定义了两个附加策略。这些策略允许限制重传次数和用户消息的优先级，以便更有效地使用发送缓冲区。
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 5741.
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 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/rfc7496.
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/rfc7496.
Copyright Notice
版权公告
Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2015 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. 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(http://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
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Additional PR-SCTP Policies . . . . . . . . . . . . . . . . . 3
3.1. Limited Retransmissions Policy . . . . . . . . . . . . . 3
3.2. Priority Policy . . . . . . . . . . . . . . . . . . . . . 4
4. Socket API Considerations . . . . . . . . . . . . . . . . . . 4
4.1. Data Types . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. Support for Added PR-SCTP Policies . . . . . . . . . . . 5
4.3. Socket Option for Getting the Stream-Specific PR-SCTP
Status (SCTP_PR_STREAM_STATUS) . . . . . . . . . . . . . 6
4.4. Socket Option for Getting the Association-Specific
PR-SCTP Status (SCTP_PR_ASSOC_STATUS) . . . . . . . . . . 7
4.5. Socket Option for Getting and Setting the PR-SCTP Support
(SCTP_PR_SUPPORTED) . . . . . . . . . . . . . . . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.1. Normative References . . . . . . . . . . . . . . . . . . 9
6.2. Informative References . . . . . . . . . . . . . . . . . 9
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Additional PR-SCTP Policies . . . . . . . . . . . . . . . . . 3
3.1. Limited Retransmissions Policy . . . . . . . . . . . . . 3
3.2. Priority Policy . . . . . . . . . . . . . . . . . . . . . 4
4. Socket API Considerations . . . . . . . . . . . . . . . . . . 4
4.1. Data Types . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. Support for Added PR-SCTP Policies . . . . . . . . . . . 5
4.3. Socket Option for Getting the Stream-Specific PR-SCTP
Status (SCTP_PR_STREAM_STATUS) . . . . . . . . . . . . . 6
4.4. Socket Option for Getting the Association-Specific
PR-SCTP Status (SCTP_PR_ASSOC_STATUS) . . . . . . . . . . 7
4.5. Socket Option for Getting and Setting the PR-SCTP Support
(SCTP_PR_SUPPORTED) . . . . . . . . . . . . . . . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.1. Normative References . . . . . . . . . . . . . . . . . . 9
6.2. Informative References . . . . . . . . . . . . . . . . . 9
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
The Partially Reliable SCTP (PR-SCTP) extension defined in [RFC3758] provides a generic method for senders to abandon user messages. The decision to abandon a user message is sender side only, and the exact condition is called a "PR-SCTP policy" ([RFC3758] refers to them as "PR-SCTP Services"). [RFC3758] also defines one particular PR-SCTP policy, called "Timed Reliability". This allows the sender to specify a timeout for a user message after which the SCTP stack abandons the user message.
[RFC3758]中定义的部分可靠SCTP（PR-SCTP）扩展为发送方放弃用户消息提供了一种通用方法。放弃用户消息的决定仅限于发送方，确切的条件称为“PR-SCTP策略”（[RFC3758]将其称为“PR-SCTP服务”）。[RFC3758]还定义了一种特殊的PR-SCTP策略，称为“定时可靠性”。这允许发送方为用户消息指定超时，在此超时之后，SCTP堆栈放弃用户消息。
This document specifies the following two additional PR-SCTP policies:
本文件规定了以下两项额外的PR-SCTP政策：
Limited Retransmission Policy: Allows limitation of the number of retransmissions.
有限重传策略：允许限制重传次数。
Priority Policy: Allows removal of lower-priority messages if space for higher-priority messages is needed in the send buffer.
优先级策略：如果发送缓冲区中需要高优先级消息的空间，则允许删除低优先级消息。
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].
本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照[RFC2119]中所述进行解释。
This section defines two new PR-SCTP policies, one in each subsection.
本节定义了两个新的PR-SCTP策略，每个小节一个。
Please note that it is REQUIRED to implement [RFC3758], if you want to implement these additional policies. However, these additional policies are OPTIONAL when implementing [RFC3758].
请注意，如果要实施这些附加策略，则需要实施[RFC3758]。但是，在实施[RFC3758]时，这些附加策略是可选的。
Using the Limited Retransmission Policy allows the sender of a user message to specify an upper limit for the number of retransmissions for each DATA chunk of the given user messages. The sender MUST abandon a user message if the number of retransmissions of any of the DATA chunks of the user message would exceed the provided limit. The sender MUST perform all other actions required for processing the retransmission event, such as adapting the congestion window and the retransmission timeout. Please note that the number of retransmissions includes both fast and timer-based retransmissions.
使用有限重传策略允许用户消息的发送方为给定用户消息的每个数据块的重传次数指定上限。如果用户消息的任何数据块的重新传输次数将超过提供的限制，则发送方必须放弃用户消息。发送方必须执行处理重传事件所需的所有其他操作，例如调整拥塞窗口和重传超时。请注意，重传次数包括快速重传和基于计时器的重传。
The sender MAY limit the number of retransmissions to 0. This will result in abandoning the message when it would get retransmitted for the first time. The use of this setting provides a service similar to UDP, which also does not perform any retransmissions.
发送方可以将重传次数限制为0。这将导致在第一次重新传输消息时放弃该消息。使用此设置可提供类似于UDP的服务，UDP也不执行任何重传。
Please note that using this policy does not affect the handling of the thresholds 'Association.Max.Retrans' and 'Path.Max.Retrans' as specified in Section 8 of [RFC4960].
请注意，使用此策略不会影响[RFC4960]第8节中规定的阈值“Association.Max.Retrans”和“Path.Max.Retrans”的处理。
The WebRTC protocol stack (see [DATA-CHAN]) is an example of where the Limited Retransmissions Policy is used.
WebRTC协议栈（参见[DATA-CHAN]）是使用有限重传策略的一个示例。
Using the Priority Policy allows the sender of a user message to specify a priority. When storing a user message in the send buffer while there is not enough available space, the SCTP stack at the sender side MAY abandon other user message(s) of the same SCTP association (with the same or a different stream) with a priority lower than the provided one. User messages sent reliably are considered to have a priority higher than all messages sent with the Priority Policy. The algorithm for selecting the message(s) being abandoned is implementation specific.
使用优先级策略允许用户邮件的发件人指定优先级。当在没有足够可用空间的情况下将用户消息存储在发送缓冲区中时，发送方侧的SCTP堆栈可以放弃具有相同SCTP关联（具有相同或不同流）的优先级低于所提供优先级的其他用户消息。可靠发送的用户消息被视为具有高于使用优先级策略发送的所有消息的优先级。选择要放弃的消息的算法是特定于实现的。
After lower-priority messages have been abandoned, high-priority messages can be transferred without the send call blocking (if used in blocking mode) or the send call failing (if used in non-blocking mode).
放弃较低优先级的消息后，可以在没有发送呼叫阻塞（如果在阻塞模式下使用）或发送呼叫失败（如果在非阻塞模式下使用）的情况下传输高优先级的消息。
The IP Flow Information Export (IPFIX) protocol stack (see [RFC7011]) is an example of where the Priority Policy can be used. Template records would be sent with full reliability, while flow records related to billing, security, and other monitoring would be sent using the Priority Policy with varying priority. The priority of security-related flow records would be set higher than the priority of monitoring-related flow records.
IP流信息导出（IPFIX）协议栈（参见[RFC7011]）是可以使用优先级策略的示例。模板记录将以完全可靠的方式发送，而与计费、安全和其他监控相关的流记录将使用优先级不同的优先级策略发送。安全相关流记录的优先级将设置为高于监控相关流记录的优先级。
This section describes how the socket API defined in [RFC6458] is extended to support the newly defined PR-SCTP policies, to provide some statistical information, and to control the negotiation of the PR-SCTP extension during the SCTP association setup.
本节介绍如何扩展[RFC6458]中定义的套接字API，以支持新定义的PR-SCTP策略，提供一些统计信息，并在SCTP关联设置期间控制PR-SCTP扩展的协商。
Please note that this section is informational only.
请注意，本节仅供参考。
This section uses data types from [IEEE.1003-1G.1997]: uintN_t means an unsigned integer of exactly N bits (e.g., uint16_t). This is the same as in [RFC6458].
本节使用[IEEE.1003-1G.1997]中的数据类型：uintN_t表示正好为N位的无符号整数（例如uint16_t）。这与[RFC6458]中的相同。
As defined in [RFC6458], the PR-SCTP policy is specified and configured by using the following sctp_prinfo structure:
如[RFC6458]中所定义，PR-SCTP策略通过使用以下SCTP_prinfo结构来指定和配置：
struct sctp_prinfo {
uint16_t pr_policy;
uint32_t pr_value;
};
struct sctp_prinfo {
uint16_t pr_policy;
uint32_t pr_value;
};
When the Limited Retransmission Policy described in Section 3.1 is used, pr_policy has the value SCTP_PR_SCTP_RTX and the number of retransmissions is given in pr_value.
当使用第3.1节中描述的有限重传策略时，pr_策略的值为SCTP_pr_SCTP_RTX，重传次数在pr_值中给出。
When using the Priority Policy described in Section 3.2, pr_policy has the value SCTP_PR_SCTP_PRIO. The priority is given in pr_value. The value of zero is the highest priority, and larger numbers in pr_value denote lower priorities.
当使用第3.2节中描述的优先级策略时，pr_策略的值为SCTP_pr_SCTP_PRIO。优先级以pr_值表示。零值是最高优先级，pr_值中的数字越大表示优先级越低。
The following table summarizes the possible parameter settings defined in [RFC6458] and this document:
下表总结了[RFC6458]和本文档中定义的可能参数设置：
+-------------------+---------------------------+---------------+
| pr_policy | pr_value | Specification |
+-------------------+---------------------------+---------------+
| SCTP_PR_SCTP_NONE | Ignored | [RFC6458] |
| SCTP_PR_SCTP_TTL | Lifetime in ms | [RFC6458] |
| SCTP_PR_SCTP_RTX | Number of retransmissions | Section 3.1 |
| SCTP_PR_SCTP_PRIO | Priority | Section 3.2 |
+-------------------+---------------------------+---------------+
+-------------------+---------------------------+---------------+
| pr_policy | pr_value | Specification |
+-------------------+---------------------------+---------------+
| SCTP_PR_SCTP_NONE | Ignored | [RFC6458] |
| SCTP_PR_SCTP_TTL | Lifetime in ms | [RFC6458] |
| SCTP_PR_SCTP_RTX | Number of retransmissions | Section 3.1 |
| SCTP_PR_SCTP_PRIO | Priority | Section 3.2 |
+-------------------+---------------------------+---------------+
4.3. Socket Option for Getting the Stream-Specific PR-SCTP Status (SCTP_PR_STREAM_STATUS)
4.3. 用于获取特定于流的PR-SCTP状态（SCTP\U PR\U流\U状态）的套接字选项
This socket option uses IPPROTO_SCTP as its level and SCTP_PR_STREAM_STATUS as its name. It can only be used with getsockopt() but not with setsockopt(). The socket option value uses the following structure:
此套接字选项使用IPPROTO_SCTP作为其级别，使用SCTP_PR_STREAM_STATUS作为其名称。它只能与getsockopt（）一起使用，但不能与setsockopt（）一起使用。套接字选项值使用以下结构：
struct sctp_prstatus {
sctp_assoc_t sprstat_assoc_id;
uint16_t sprstat_sid;
uint16_t sprstat_policy;
uint64_t sprstat_abandoned_unsent;
uint64_t sprstat_abandoned_sent;
};
struct sctp_prstatus {
sctp_assoc_t sprstat_assoc_id;
uint16_t sprstat_sid;
uint16_t sprstat_policy;
uint64_t sprstat_abandoned_unsent;
uint64_t sprstat_abandoned_sent;
};
sprstat_assoc_id: This parameter is ignored for one-to-one style sockets. For one-to-many style sockets, this parameter indicates for which association the user wants the information. It is an error to use SCTP_{CURRENT|ALL|FUTURE}_ASSOC in sprstat_assoc_id.
sprstat\u assoc\u id：对于一对一样式的套接字，此参数被忽略。对于一对多样式套接字，此参数指示用户希望获得信息的关联。在sprstat_ASSOC_id中使用SCTP_124;CURRENT | ALL | FUTURE | u ASSOC是错误的。
sprstat_sid: This parameter indicates for which outgoing SCTP stream the user wants the information.
sprstat_sid：此参数指示用户希望获得哪个传出SCTP流的信息。
sprstat_policy: This parameter indicates for which PR-SCTP policy the user wants the information. It is an error to use SCTP_PR_SCTP_NONE in sprstat_policy. If SCTP_PR_SCTP_ALL is used, the counters provided are aggregated over all supported policies.
sprstat_策略：此参数指示用户希望获取信息的PR-SCTP策略。在sprstat_策略中使用SCTP_PR_SCTP_NONE是错误的。如果使用SCTP_PR_SCTP_ALL，则提供的计数器将聚合到所有支持的策略上。
sprstat_abandoned_unsent: The number of user messages that have been abandoned using the policy specified in sprstat_policy on the stream specified in sprstat_sid for the association specified by sprstat_assoc_id, before any part of the user message could be sent.
sprstat_Forwarded_unsent：在发送用户消息的任何部分之前，在sprstat_sid为sprstat_assoc_id指定的关联指定的流上，使用sprstat_策略中指定的策略放弃的用户消息数。
sprstat_abandoned_sent: The number of user messages that have been abandoned using the policy specified in sprstat_policy on the stream specified in sprstat_sid for the association specified by sprstat_assoc_id, after a part of the user message has been sent.
已发送的sprstat_放弃的用户消息数：发送部分用户消息后，在sprstat_sid中为sprstat_assoc_id指定的关联指定的流上，使用sprstat_策略中指定的策略放弃的用户消息数。
There are separate counters for unsent and sent user messages because the SCTP_SEND_FAILED_EVENT supports a similar differentiation. Please note that an abandoned large user message requiring SCTP-level fragmentation is reported in the sprstat_abandoned_sent counter as soon as at least one fragment of it has been sent. Therefore, each abandoned user message is counted in either sprstat_abandoned_unsent or sprstat_abandoned_sent.
由于SCTP_SEND_FAILED_事件支持类似的区分，未发送和已发送的用户消息有单独的计数器。请注意，一条需要SCTP级别碎片的废弃大用户消息在至少发送了一个碎片后，会立即在sprstat_遗弃_发送计数器中报告。因此，每个被放弃的用户消息都会计入sprstat_dependend_unsent或sprstat_dependend_sent中。
If more detailed information about abandoned user messages is required, the subscription to the SCTP_SEND_FAILED_EVENT is recommended. Please note that some implementations might choose not to support this option, since it increases the resources needed for an outgoing SCTP stream. For the same reasons, some implementations might only support using SCTP_PR_SCTP_ALL in sprstat_policy.
如果需要有关已放弃用户消息的更详细信息，建议订阅SCTP_SEND_FAILED_事件。请注意，一些实现可能选择不支持此选项，因为它增加了传出SCTP流所需的资源。出于同样的原因，某些实现可能只支持使用SCTP_PR_SCTP_ALL-in-sprstat_策略。
sctp_opt_info() needs to be extended to support SCTP_PR_STREAM_STATUS.
sctp_opt_info（）需要扩展以支持sctp_PR_STREAM_状态。
4.4. Socket Option for Getting the Association-Specific PR-SCTP Status (SCTP_PR_ASSOC_STATUS)
4.4. 用于获取关联特定PR-SCTP状态（SCTP\U PR\U ASSOC\U状态）的套接字选项
This socket option uses IPPROTO_SCTP as its level and SCTP_PR_ASSOC_STATUS as its name. It can only be used with getsockopt(), but not with setsockopt(). The socket option value uses the same structure as described in Section 4.3:
此套接字选项使用IPPROTO_SCTP作为其级别，使用SCTP_PR_ASSOC_STATUS作为其名称。它只能与getsockopt（）一起使用，但不能与setsockopt（）一起使用。插座选项值使用与第4.3节所述相同的结构：
struct sctp_prstatus {
sctp_assoc_t sprstat_assoc_id;
uint16_t sprstat_sid;
uint16_t sprstat_policy;
uint64_t sprstat_abandoned_unsent;
uint64_t sprstat_abandoned_sent;
};
struct sctp_prstatus {
sctp_assoc_t sprstat_assoc_id;
uint16_t sprstat_sid;
uint16_t sprstat_policy;
uint64_t sprstat_abandoned_unsent;
uint64_t sprstat_abandoned_sent;
};
sprstat_assoc_id: This parameter is ignored for one-to-one style sockets. For one-to-many style sockets, this parameter indicates for which association the user wants the information. It is an error to use SCTP_{CURRENT|ALL|FUTURE}_ASSOC in sprstat_assoc_id.
sprstat\u assoc\u id：对于一对一样式的套接字，此参数被忽略。对于一对多样式套接字，此参数指示用户希望获得信息的关联。在sprstat_ASSOC_id中使用SCTP_124;CURRENT | ALL | FUTURE | u ASSOC是错误的。
sprstat_sid: This parameter is ignored.
sprstat_sid:忽略此参数。
sprstat_policy: This parameter indicates for which PR-SCTP policy the user wants the information. It is an error to use SCTP_PR_SCTP_NONE in sprstat_policy. If SCTP_PR_SCTP_ALL is used, the counters provided are aggregated over all supported policies.
sprstat_策略：此参数指示用户希望获取信息的PR-SCTP策略。在sprstat_策略中使用SCTP_PR_SCTP_NONE是错误的。如果使用SCTP_PR_SCTP_ALL，则提供的计数器将聚合到所有支持的策略上。
sprstat_abandoned_unsent: The number of user messages that have been abandoned using the policy specified in sprstat_policy for the association specified by sprstat_assoc_id, before any part of the user message could be sent.
sprstat_Forwarded_unsent：在发送用户消息的任何部分之前，使用sprstat_策略中为sprstat_assoc_id指定的关联指定的策略放弃的用户消息数。
sprstat_abandoned_sent: The number of user messages that have been abandoned using the policy specified in sprstat_policy for the association specified by sprstat_assoc_id, after a part of the user message has been sent.
已发送的sprstat_放弃的用户消息数：发送部分用户消息后，使用sprstat_策略中为sprstat_assoc_id指定的关联指定的策略放弃的用户消息数。
There are separate counters for unsent and sent user messages because the SCTP_SEND_FAILED_EVENT supports a similar differentiation. Please note that an abandoned large user message requiring SCTP-level fragmentation is reported in the sprstat_abandoned_sent counter as soon as at least one fragment of it has been sent. Therefore, each abandoned user message is counted in either sprstat_abandoned_unsent or sprstat_abandoned_sent.
由于SCTP_SEND_FAILED_事件支持类似的区分，未发送和已发送的用户消息有单独的计数器。请注意，一条需要SCTP级别碎片的废弃大用户消息在至少发送了一个碎片后，会立即在sprstat_遗弃_发送计数器中报告。因此，每个被放弃的用户消息都会计入sprstat_dependend_unsent或sprstat_dependend_sent中。
If more detailed information about abandoned user messages is required, the usage of the option described in Section 4.3 or the subscription to the SCTP_SEND_FAILED_EVENT is recommended.
如果需要更详细的废弃用户消息信息，建议使用第4.3节中描述的选项或订阅SCTP_SEND_FAILED_事件。
sctp_opt_info() needs to be extended to support SCTP_PR_ASSOC_STATUS.
需要扩展sctp_opt_info（），以支持sctp_PR_ASSOC_状态。
4.5. Socket Option for Getting and Setting the PR-SCTP Support (SCTP_PR_SUPPORTED)
4.5. 获取和设置PR-SCTP支持的套接字选项（支持SCTP\U PR\U）
This socket option allows the enabling or disabling of the negotiation of PR-SCTP support for future associations. For existing associations, it allows one to query whether or not PR-SCTP support was negotiated on a particular association.
此套接字选项允许启用或禁用未来关联的PR-SCTP支持协商。对于现有关联，它允许用户查询PR-SCTP支持是否在特定关联上协商。
Whether or not PR-SCTP is enabled by default is implementation specific.
默认情况下是否启用PR-SCTP取决于具体实现。
This socket option uses IPPROTO_SCTP as its level and SCTP_PR_SUPPORTED as its name. It can be used with getsockopt() and setsockopt(). The socket option value uses the following structure defined in [RFC6458]:
此套接字选项使用IPPROTO_SCTP作为其级别，SCTP_PR_SUPPORTED作为其名称。它可以与getsockopt（）和setsockopt（）一起使用。套接字选项值使用[RFC6458]中定义的以下结构：
struct sctp_assoc_value {
sctp_assoc_t assoc_id;
uint32_t assoc_value;
};
struct sctp_assoc_value {
sctp_assoc_t assoc_id;
uint32_t assoc_value;
};
assoc_id: This parameter is ignored for one-to-one style sockets. For one-to-many style sockets, this parameter indicates upon which association the user is performing an action. The special sctp_assoc_t SCTP_FUTURE_ASSOC can also be used; it is an error to use SCTP_{CURRENT|ALL}_ASSOC in assoc_id.
assoc_id：对于一对一样式的套接字，此参数被忽略。对于一对多样式套接字，此参数指示用户执行操作的关联。也可使用特殊的sctp_assoc_t sctp_FUTURE_assoc；在ASSOC_id中使用SCTP_u{CURRENT | ALL}ASSOC是一个错误。
assoc_value: A non-zero value encodes the enabling of PR-SCTP, whereas a value of 0 encodes the disabling of PR-SCTP.
assoc_值：非零值表示启用PR-SCTP，而0表示禁用PR-SCTP。
sctp_opt_info() needs to be extended to support SCTP_PR_SUPPORTED.
需要扩展sctp_opt_info（）以支持支持支持的sctp_PR_。
This document does not add any security considerations to those given in [RFC4960], [RFC3758], and [RFC6458]. As indicated in the Security Considerations of [RFC3758], transport-layer security in the form of TLS over SCTP (see [RFC3436]) can't be used for PR-SCTP. However, DTLS over SCTP (see [RFC6083]) could be used instead. If DTLS over SCTP as specified in [RFC6083] is used, the Security Considerations of [RFC6083] do apply. It should also be noted that using PR-SCTP for an SCTP association doesn't allow that association to behave more aggressively than an SCTP association not using PR-SCTP.
本文件未在[RFC4960]、[RFC3758]和[RFC6458]中给出的安全注意事项之外添加任何安全注意事项。如[RFC3758]中的安全注意事项所示，SCTP上TLS形式的传输层安全（参见[RFC3436]）不能用于PR-SCTP。但是，可以使用SCTP上的DTL（参见[RFC6083]）。如果使用[RFC6083]中规定的通过SCTP的DTL，则[RFC6083]中的安全注意事项适用。还应注意，对SCTP关联使用PR-SCTP不允许该关联的行为比不使用PR-SCTP的SCTP关联更具攻击性。
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997, <http://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 2119，1997年3月<http://www.rfc-editor.org/info/rfc2119>.
[RFC3758] Stewart, R., Ramalho, M., Xie, Q., Tuexen, M., and P. Conrad, "Stream Control Transmission Protocol (SCTP) Partial Reliability Extension", RFC 3758, May 2004, <http://www.rfc-editor.org/info/rfc3758>.
[RFC3758]Stewart，R.，Ramalho，M.，Xie，Q.，Tuexen，M.，和P.Conrad，“流控制传输协议（SCTP）部分可靠性扩展”，RFC 3758，2004年5月<http://www.rfc-editor.org/info/rfc3758>.
[RFC4960] Stewart, R., Ed., "Stream Control Transmission Protocol", RFC 4960, September 2007, <http://www.rfc-editor.org/info/rfc4960>.
[RFC4960]Stewart，R.，Ed.“流控制传输协议”，RFC 49602007年9月<http://www.rfc-editor.org/info/rfc4960>.
[RFC3436] Jungmaier, A., Rescorla, E., and M. Tuexen, "Transport Layer Security over Stream Control Transmission Protocol", RFC 3436, December 2002, <http://www.rfc-editor.org/info/rfc3436>.
[RFC3436]Jungmaier，A.，Rescorla，E.，和M.Tuexen，“流控制传输协议上的传输层安全”，RFC 3436，2002年12月<http://www.rfc-editor.org/info/rfc3436>.
[RFC6083] Tuexen, M., Seggelmann, R., and E. Rescorla, "Datagram Transport Layer Security (DTLS) for Stream Control Transmission Protocol (SCTP)", RFC 6083, January 2011, <http://www.rfc-editor.org/info/rfc6083>.
[RFC6083]Tuexen，M.，Seggelmann，R.，和E.Rescorla，“流控制传输协议（SCTP）的数据报传输层安全性（DTLS）”，RFC 6083，2011年1月<http://www.rfc-editor.org/info/rfc6083>.
[RFC6458] Stewart, R., Tuexen, M., Poon, K., Lei, P., and V. Yasevich, "Sockets API Extensions for the Stream Control Transmission Protocol (SCTP)", RFC 6458, December 2011, <http://www.rfc-editor.org/info/rfc6458>.
[RFC6458]Stewart，R.，Tuexen，M.，Poon，K.，Lei，P.，和V.Yasevich，“流控制传输协议（SCTP）的套接字API扩展”，RFC 6458，2011年12月<http://www.rfc-editor.org/info/rfc6458>.
[RFC7011] Claise, B., Ed., Trammell, B., Ed., and P. Aitken, "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of Flow Information", STD 77, RFC 7011, September 2013, <http://www.rfc-editor.org/info/rfc7011>.
[RFC7011]Claise，B.，Ed.，Trammell，B.，Ed.，和P.Aitken，“流量信息交换的IP流量信息导出（IPFIX）协议规范”，STD 77，RFC 7011，2013年9月<http://www.rfc-editor.org/info/rfc7011>.
[DATA-CHAN] Jesup, R., Loreto, S., and M. Tuexen, "WebRTC Data Channels", Work in Progress, draft-ietf-rtcweb-data-channel-13, January 2015.
[DATA-CHAN]Jesup，R.，Loreto，S.，和M.Tuexen，“WebRTC数据通道”，正在进行的工作，草稿-ietf-rtcweb-DATA-channel-13，2015年1月。
[IEEE.1003-1G.1997] IEEE, "Protocol Independent Interfaces", IEEE Standard 1003.1G, March 1997.
[IEEE.1003-1G.1997]IEEE，“协议独立接口”，IEEE标准1003.1G，1997年3月。
Acknowledgments
致谢
The authors wish to thank Benoit Claise, Spencer Dawkins, Gorry Fairhurst, Stephen Farrell, Barry Leiba, Karen Egede Nielsen, Ka-Cheong Poon, Dan Romascanu, Irene Ruengeler, Jamal Hadi Salim, Joseph Salowey, Brian Trammell, and Vlad Yasevich for their invaluable comments.
作者要感谢Benoit Claise、Spencer Dawkins、Gorry Fairhurst、Stephen Farrell、Barry Leiba、Karen Egede Nielsen、Ka Chang Poon、Dan Romascan、Irene Ruengeler、Jamal Hadi Salim、Joseph Salowey、Brian Trammell和Vlad Yasevich的宝贵评论。
Authors' Addresses
作者地址
Michael Tuexen Muenster University of Applied Sciences Stegerwaldstrasse 39 48565 Steinfurt Germany
米迦勒TuxEN明斯特应用科学大学StugWaldStasSE 39 48565斯坦福特德国
EMail: tuexen@fh-muenster.de
EMail: tuexen@fh-muenster.de
Robin Seggelmann Metafinanz Informationssysteme GmbH Leopoldstrasse 146 80804 Muenchen Germany
Robin Seggelmann Metafinanz Information System GmbH Leopoldstrasse 146 80804德国慕尼黑
EMail: rfc@robin-seggelmann.com
EMail: rfc@robin-seggelmann.com
Randall R. Stewart Netflix, Inc. Chapin, SC 29036 United States
Randall R.Stewart Netflix，Inc.Chapin，SC 29036美国
EMail: randall@lakerest.net
EMail: randall@lakerest.net
Salvatore Loreto Ericsson Hirsalantie 11 Jorvas 02420 Finland
萨尔瓦托·洛雷托·爱立信·赫萨兰蒂11 Jorvas 02420芬兰
EMail: Salvatore.Loreto@ericsson.com
EMail: Salvatore.Loreto@ericsson.com