Internet Engineering Task Force (IETF)                 S. Perreault, Ed.
Request for Comments: 6888                                      Viagenie
BCP: 127                                                     I. Yamagata
Updates: 4787                                                S. Miyakawa
Category: Best Current Practice                       NTT Communications
ISSN: 2070-1721                                              A. Nakagawa
                                          Japan Internet Exchange (JPIX)
                                                               H. Ashida
                                                           Cisco Systems
                                                              April 2013
Internet Engineering Task Force (IETF)                 S. Perreault, Ed.
Request for Comments: 6888                                      Viagenie
BCP: 127                                                     I. Yamagata
Updates: 4787                                                S. Miyakawa
Category: Best Current Practice                       NTT Communications
ISSN: 2070-1721                                              A. Nakagawa
                                          Japan Internet Exchange (JPIX)
                                                               H. Ashida
                                                           Cisco Systems
                                                              April 2013

Common Requirements for Carrier-Grade NATs (CGNs)




This document defines common requirements for Carrier-Grade NATs (CGNs). It updates RFC 4787.


Status of This Memo


This memo documents an Internet Best Current Practice.


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 BCPs 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BCP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


Copyright Notice


Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved.

版权所有(c)2013 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 ( 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(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
   1. Introduction . . . . . . . . . . . . . . . . . . . . . . . .  2
   2. Terminology  . . . . . . . . . . . . . . . . . . . . . . . .  3
   3. Requirements for CGNs  . . . . . . . . . . . . . . . . . . .  4
   4. Logging  . . . . . . . . . . . . . . . . . . . . . . . . . . 10
   5. Port Allocation Scheme . . . . . . . . . . . . . . . . . . . 11
   6. Deployment Considerations  . . . . . . . . . . . . . . . . . 11
   7. Security Considerations  . . . . . . . . . . . . . . . . . . 12
   8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
   9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
      9.1. Normative References  . . . . . . . . . . . . . . . . . 12
      9.2. Informative Reference . . . . . . . . . . . . . . . . . 13
Table of Contents
   1. Introduction . . . . . . . . . . . . . . . . . . . . . . . .  2
   2. Terminology  . . . . . . . . . . . . . . . . . . . . . . . .  3
   3. Requirements for CGNs  . . . . . . . . . . . . . . . . . . .  4
   4. Logging  . . . . . . . . . . . . . . . . . . . . . . . . . . 10
   5. Port Allocation Scheme . . . . . . . . . . . . . . . . . . . 11
   6. Deployment Considerations  . . . . . . . . . . . . . . . . . 11
   7. Security Considerations  . . . . . . . . . . . . . . . . . . 12
   8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
   9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
      9.1. Normative References  . . . . . . . . . . . . . . . . . 12
      9.2. Informative Reference . . . . . . . . . . . . . . . . . 13
1. Introduction
1. 介绍

With the shortage of IPv4 addresses, it is expected that more Internet Service Providers (ISPs) may want to provide a service where a public IPv4 address would be shared by many subscribers. Each subscriber is assigned a private address, and a Network Address Translator (NAT) [RFC2663] situated in the ISP's network translates the traffic between private and public addresses. When a second IPv4 NAT is located at the customer edge, this results in two layers of NAT.

由于IPv4地址短缺,预计会有更多的互联网服务提供商(ISP)希望提供公共IPv4地址由多个订户共享的服务。每个订户都被分配一个专用地址,位于ISP网络中的网络地址转换器(NAT)[RFC2663]转换专用地址和公共地址之间的通信量。当第二个IPv4 NAT位于客户边缘时,将产生两层NAT。

This service can conceivably be offered alongside others, such as IPv6 services or regular IPv4 service assigning public addresses to subscribers. Some ISPs started offering such a service long before there was a shortage of IPv4 addresses, showing that there are driving forces other than the shortage of IPv4 addresses. One approach to CGN deployment is described in [RFC6264].


This document describes behavior that is required of those multi-subscriber NATs for interoperability. It is not an IETF endorsement of CGNs or a real specification for CGNs; rather, it is just a minimal set of requirements that will increase the likelihood of applications working across CGNs.


Because subscribers do not receive unique IPv4 addresses, Carrier-Grade NATs introduce substantial limitations in communications between subscribers and with the rest of the Internet. In particular, it is considerably more involved to establish proxy functionality at the border between internal and external realms. Some applications may require substantial enhancements, while some others may not function at all in such an environment. Please see "Issues with IP Address Sharing" [RFC6269] for details.


This document builds upon previous works describing requirements for generic NATs [RFC4787][RFC5382][RFC5508]. These documents, and their updates if any, still apply in this context. What follows are additional requirements, to be satisfied on top of previous ones.


2. Terminology
2. 术语

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].


Readers are expected to be familiar with "Network Address Translation (NAT) Behavioral Requirements for Unicast UDP" [RFC4787] and the terms defined there. The following additional term is used in this document:


Carrier-Grade NAT (CGN): A NAT-based [RFC2663] logical function used to share the same IPv4 address among several subscribers. A CGN is not managed by the subscribers.


Note that the term "carrier-grade" has nothing to do with the quality of the NAT; that is left to discretion of implementers. Rather, it is to be understood as a topological qualifier: the NAT is placed in an ISP's network and translates the traffic of potentially many subscribers. Subscribers have limited or no control over the CGN, whereas they typically have full control over a NAT placed on their premises.


Note also that the CGN described in this document is IPv4-only. IPv6 address translation is not considered.


However, the scenario in which the IPv4-only CGN logical function is used may include IPv6 elements. For example, Dual-Stack Lite (DS-Lite) [RFC6333] uses an IPv4-only CGN logical function in a scenario making use of IPv6 encapsulation. Therefore, this document would also apply to the CGN part of DS-Lite.

但是,使用仅IPv4 CGN逻辑功能的场景可能包括IPv6元素。例如,双栈Lite(DS Lite)[RFC6333]在使用IPv6封装的场景中使用仅IPv4的CGN逻辑函数。因此,本文件也适用于DS Lite的CGN部分。

Figure 1 summarizes a common network topology in which a CGN operates.


                                   |       Internet
                   ............... | ...................
                                   |       ISP network
                   External pool:  |
                               ++------++  External realm
                   ........... |  CGN   |...............
                               ++------++  Internal realm
               |    |
                                 |    |
                                 |    |    ISP network
                   ............. | .. | ................
                                 |    |  Customer premises
             |    |
                         ++------++  ++------++
                         |  CPE1  |  |  CPE2  |  etc.
                         ++------++  ++------++
                                   |       Internet
                   ............... | ...................
                                   |       ISP network
                   External pool:  |
                               ++------++  External realm
                   ........... |  CGN   |...............
                               ++------++  Internal realm
               |    |
                                 |    |
                                 |    |    ISP network
                   ............. | .. | ................
                                 |    |  Customer premises
             |    |
                         ++------++  ++------++
                         |  CPE1  |  |  CPE2  |  etc.
                         ++------++  ++------++

(IP addresses are only for example purposes)


Figure 1: CGN Network Topology


Another possible topology is one for hotspots, where there is no customer premise or customer premises equipment (CPE), but where a CGN serves a bunch of customers who don't trust each other; hence, fairness is an issue. One important difference with the previous topology is the absence of a second layer of NAT. This, however, has no impact on CGN requirements since they are driven by fairness and robustness in the service provided to customers, which applies in both cases.


3. Requirements for CGNs
3. 对CGN的要求

What follows is a list of requirements for CGNs. They are in addition to those found in other documents such as [RFC4787], [RFC5382], and [RFC5508].


REQ-1: If a CGN forwards packets containing a given transport protocol, then it MUST fulfill that transport protocol's behavioral requirements. Current applicable documents are as follows:


a. "NAT Behavioral Requirements for Unicast UDP" [RFC4787]

a. “单播UDP的NAT行为要求”[RFC4787]

b. "Network Address Translation (NAT) Behavioral Requirements for TCP" [RFC5382]

b. “TCP的网络地址转换(NAT)行为要求”[RFC5382]

c. "NAT Behavioral Requirements for ICMP" [RFC5508]

c. “ICMP的NAT行为要求”[RFC5508]

d. "Network Address Translation (NAT) Behavioral Requirements for the Datagram Congestion Control Protocol (DCCP)" [RFC5597]

d. “数据报拥塞控制协议(DCCP)的网络地址转换(NAT)行为要求”[RFC5597]

Any future NAT behavioral requirements documents for IPv4 transport protocols will impose additional requirements for CGNs on top of those stated here.


Justification: It is crucial for CGNs to maximize the set of applications that can function properly across them. The IETF has documented the best current practices for UDP, TCP, ICMP, and DCCP.


REQ-2: A CGN MUST have a default "IP address pooling" behavior of "Paired" (as defined in Section 4.1 of [RFC4787]). A CGN MAY provide a mechanism for administrators to change this behavior on an application protocol basis.


* When multiple overlapping internal IP address ranges share the same external IP address pool (e.g., DS-Lite [RFC6333]), the "IP address pooling" behavior applies to mappings between external IP addresses and internal subscribers rather than between external and internal IP addresses.

* 当多个重叠的内部IP地址范围共享同一个外部IP地址池(例如,DS Lite[RFC6333])时,“IP地址池”行为适用于外部IP地址和内部订户之间的映射,而不是外部IP地址和内部IP地址之间的映射。

Justification: This stronger form of REQ-2 from [RFC4787] is justified by the stronger need for not breaking applications that depend on the external address remaining constant.


Note that this requirement applies regardless of the transport protocol. In other words, a CGN must use the same external IP address mapping for all sessions associated with the same internal IP address, be they TCP, UDP, ICMP, something else, or a mix of different protocols.


The justification for allowing other behaviors is to allow the administrator to save external addresses and ports for application protocols that are known to work fine with other behaviors in practice. However, the default behavior MUST be "Paired".


REQ-3: The CGN function SHOULD NOT have any limitations on the size or the contiguity of the external address pool. In particular, the CGN function MUST be configurable with contiguous or non-contiguous external IPv4 address ranges.


Justification: Given the increasing rarity of IPv4 addresses, it is becoming harder for an operator to provide large contiguous address pools to CGNs. Additionally, operational flexibility may require non-contiguous address pools for reasons such as differentiated services, routing management, etc.


The reason for having SHOULD instead of MUST is to account for limitations imposed by available resources as well as constraints imposed for security reasons.


REQ-4: A CGN MUST support limiting the number of external ports (or, equivalently, "identifiers" for ICMP) that are assigned per subscriber.


a. Per-subscriber limits MUST be configurable by the CGN administrator.

a. 每个订户的限制必须由CGN管理员配置。

b. Per-subscriber limits MAY be configurable independently per transport protocol.

b. 每个用户的限制可以根据传输协议独立配置。

c. Additionally, it is RECOMMENDED that the CGN include administrator-adjustable thresholds to prevent a single subscriber from consuming excessive CPU resources from the CGN (e.g., rate-limit the subscriber's creation of new mappings).

c. 此外,建议CGN包括管理员可调整的阈值,以防止单个订户从CGN消耗过多的CPU资源(例如,速率限制订户创建新映射)。

Justification: A CGN can be considered a network resource that is shared by competing subscribers. Limiting the number of external ports assigned to each subscriber mitigates the denial-of-service (DoS) attack that a subscriber could launch against other subscribers through the CGN in order to get a larger share of the resource. It ensures fairness among subscribers. Limiting the rate of allocation mitigates a similar attack where the CPU is the resource being targeted instead of port numbers. However, this requirement is not a MUST because it is very hard to explicitly call out all CPU-consuming events.


REQ-5: A CGN SHOULD support limiting the amount of state memory allocated per mapping and per subscriber. This may include limiting the number of sessions, the number of filters, etc., depending on the NAT implementation.


a. Limits SHOULD be configurable by the CGN administrator.

a. 限制应由CGN管理员配置。

b. Additionally, it SHOULD be possible to limit the rate at which memory-consuming state elements are allocated.

b. 此外,应该可以限制分配内存消耗状态元素的速率。

Justification: A NAT needs to keep track of TCP sessions associated with each mapping. This state consumes resources for which, in the case of a CGN, subscribers may compete. It is necessary to ensure that each subscriber has access to a fair share of the CGN's resources. Limiting the rate of allocation is intended to prevent CPU resource exhaustion. Item "B" is at the SHOULD level to account for the fact that means other than rate limiting may be used to attain the same goal.


REQ-6: It MUST be possible to administratively turn off translation for specific destination addresses and/or ports.


Justification: It is common for a CGN administrator to provide access for subscribers to servers installed in the ISP's network in the external realm. When such a server is able to reach the internal realm via normal routing (which is entirely controlled by the ISP), translation is unneeded. In that case, the CGN may forward packets without modification, thus acting like a plain router. This may represent an important efficiency gain.


Figure 2 illustrates this use-case.


                  X1:x1            X1':x1'            X2:x2
                  +---+from X1:x1  +---+from X1:x1    +---+
                  | C |  to X2:x2  |   |  to X2:x2    | S |
                  | l |>>>>>>>>>>>>| C |>>>>>>>>>>>>>>| e |
                  | i |            | G |              | r |
                  | e |<<<<<<<<<<<<| N |<<<<<<<<<<<<<<| v |
                  | n |from X2:x2  |   |from X2:x2    | e |
                  | t |  to X1:x1  |   |  to X1:x1    | r |
                  +---+            +---+              +---+
                  X1:x1            X1':x1'            X2:x2
                  +---+from X1:x1  +---+from X1:x1    +---+
                  | C |  to X2:x2  |   |  to X2:x2    | S |
                  | l |>>>>>>>>>>>>| C |>>>>>>>>>>>>>>| e |
                  | i |            | G |              | r |
                  | e |<<<<<<<<<<<<| N |<<<<<<<<<<<<<<| v |
                  | n |from X2:x2  |   |from X2:x2    | e |
                  | t |  to X1:x1  |   |  to X1:x1    | r |
                  +---+            +---+              +---+

Figure 2: CGN Pass-Through


REQ-7: It is RECOMMENDED that a CGN use an "endpoint-independent filtering" behavior (as defined in Section 5 of [RFC4787]). If it is known that "Address-Dependent Filtering" does not cause the application-layer protocol to break (how to determine this is out of scope for this document), then it MAY be used instead.


Justification: This is a stronger form of REQ-8 from [RFC4787]. This is based on the observation that some games and peer-to-peer applications require EIF for the NAT traversal to work. In the context of a CGN, it is important to minimize application breakage.


REQ-8: Once an external port is deallocated, it SHOULD NOT be reallocated to a new mapping until at least 120 seconds have passed, with the exceptions being:


a. If the CGN tracks TCP sessions (e.g., with a state machine, as in Section of [RFC6146]), TCP ports MAY be reused immediately.

a. 如果CGN跟踪TCP会话(例如,使用状态机,如[RFC6146]第3.5.2.2节所述),则可以立即重用TCP端口。

b. If external ports are statically assigned to internal addresses (e.g., address X with port range 1000-1999 is assigned to subscriber A, 2000-2999 to subscriber B, etc.), and the assignment remains constant across state loss, then ports MAY be reused immediately.

b. 如果静态地将外部端口分配给内部地址(例如,端口范围为1000-1999的地址X分配给订户A,2000-2999分配给订户B等),并且在状态丢失期间分配保持不变,则可以立即重用端口。

c. If the allocated external ports used address-dependent or address-and-port-dependent filtering before state loss, they MAY be reused immediately.

c. 如果分配的外部端口在状态丢失之前使用了地址相关过滤或地址和端口相关过滤,则可以立即重用这些端口。

The length of time and the maximum number of ports in this state MUST be configurable by the CGN administrator.


Justification: This is necessary in order to prevent collisions between old and new mappings and sessions. It ensures that all established sessions are broken instead of redirected to a different peer.


The exceptions are for cases where reusing a port immediately does not create a possibility that packets would be redirected to the wrong peer. One can imagine other exceptions where mapping collisions are avoided, thus justifying the SHOULD level for this requirement.


The 120 seconds value corresponds to the Maximum Segment Lifetime (MSL) from [RFC0793].


Note that this requirement also applies to the case when a CGN loses state (due to a crash, reboot, failover to a cold standby, etc.). In that case, ports that were in use at the time of state loss SHOULD NOT be reallocated until at least 120 seconds have passed.


REQ-9: A CGN MUST implement a protocol giving subscribers explicit control over NAT mappings. That protocol SHOULD be the Port Control Protocol [RFC6887].


Justification: Allowing subscribers to manipulate the NAT state table with PCP greatly increases the likelihood that applications will function properly.


A study of PCP-less CGN impacts can be found in [NAT444]. Another study considering the effects of PCP on a peer-to-peer file sharing protocol can be found in [BITTORRENT].


REQ-10: CGN implementers SHOULD make their equipment manageable. Standards-based management using standards such as "Definitions of Managed Objects for NAT" [RFC4008] is RECOMMENDED.


Justification: It is anticipated that CGNs will be primarily deployed in ISP networks where the need for management is critical. This requirement is at the SHOULD level to account for the fact that some CGN operators may not need management functionality.


Note also that there are efforts within the IETF toward creating a MIB tailored for CGNs (e.g., [NAT-MIB]).


REQ-11: When a CGN is unable to create a dynamic mapping due to resource constraints or administrative restrictions (i.e., quotas):


a. it MUST drop the original packet;

a. 它必须丢弃原始数据包;

b. it SHOULD send an ICMP Destination Unreachable message with code 1 (Host Unreachable) to the sender;

b. 它应该向发送方发送一条代码为1(主机不可访问)的ICMP目的地不可访问消息;

c. it SHOULD send a notification (e.g., SNMP trap) towards a management system (if configured to do so); and

c. 它应该向管理系统发送通知(例如SNMP陷阱)(如果配置为这样做);和

d. it MUST NOT delete existing mappings in order to "make room" for the new one. (This only applies to normal CGN behavior, not to manual operator intervention.)

d. 它不能为了给新映射“腾出空间”而删除现有映射。(这仅适用于正常CGN行为,不适用于手动操作员干预。)

Justification: This is a slightly different form of REQ-8 from [RFC5508]. Code 1 is preferred to code 13 because it is listed as a "soft error" in [RFC1122], which is important because we don't want TCP stacks to abort the connection attempt in this case. See [RFC5461] for details on TCP's reaction to soft errors.


Sending ICMP errors and SNMP traps may be rate-limited for security reasons, which is why requirements B and C are SHOULDs, not MUSTs.


Applications generally handle connection establishment failure better than established connection failure. This is why dropping the packet initiating the new connection is preferred over deleting existing mappings. See also the rationale in Section 6 of [RFC5508].


4. Logging
4. 登录中

It may be necessary for CGN administrators to be able to identify a subscriber based on external IPv4 address, port, and timestamp in order to deal with abuse. When multiple subscribers share a single external address, the source address and port that are visible at the destination host have been translated from the ones originated by the subscriber.


In order to be able to do this, the CGN would need to log the following information for each mapping created (this list is for informational purposes only and does not constitute a requirement):


o transport protocol

o 传输协议

o subscriber identifier (e.g., internal source address or tunnel endpoint identifier)

o 订户标识符(例如,内部源地址或隧道端点标识符)

o external source address

o 外部源地址

o external source port

o 外部源端口

o timestamp

o 时间戳

By "subscriber identifier" we mean information that uniquely identifies a subscriber. For example, in a traditional NAT scenario, the internal source address would be sufficient. In the case of DS-Lite, many subscribers share the same internal address and the subscriber identifier is the tunnel endpoint identifier (i.e., the B4's IPv6 address).

“订户标识符”是指唯一标识订户的信息。例如,在传统的NAT场景中,内部源地址就足够了。在DS Lite的情况下,许多订户共享相同的内部地址,订户标识符是隧道端点标识符(即B4的IPv6地址)。

A disadvantage of logging mappings is that CGNs under heavy usage may produce large amounts of logs, which may require large storage volume.


REQ-12: A CGN SHOULD NOT log destination addresses or ports unless required to do so for administrative reasons.


Justification: Destination logging at the CGN creates privacy issues. Furthermore, readers should be aware of logging recommendations for Internet-facing servers [RFC6302]. With compliant servers, the destination address and port do not need to be logged by the CGN. This can help reduce the amount of logging.


This requirement is at the SHOULD level to account for the fact that there may be other reasons for logging destination addresses or ports. One such reason might be that the remote server is not following [RFC6302].


5. Port Allocation Scheme
5. 港口分配计划

A CGN's port allocation scheme is subject to three competing requirements:


REQ-13: A CGN's port allocation scheme SHOULD maximize port utilization.


Justification: External ports are one of the resources being shared by a CGN. Efficient management of that resource directly impacts the quality of a subscriber's Internet connection.


Some schemes are very efficient in their port utilization. In that sense, they have good scaling properties (nothing is wasted). Others will systematically waste ports.


REQ-14: A CGN's port allocation scheme SHOULD minimize log volume.


Justification: Huge log volumes can be problematic to CGN operators.


Some schemes create one log entry per mapping. Others allow multiple mappings to generate a single log entry, which sometimes can be expressed very compactly. With some schemes, the logging frequency can approach that of DHCP servers.


REQ-15: A CGN's port allocation scheme SHOULD make it hard for attackers to guess port numbers.


Justification: Easily guessed port numbers put subscribers at risk of the attacks described in [RFC6056].


Some schemes provide very good security in that ports numbers are not easily guessed. Others provide poor security to subscribers.


A CGN implementation's choice of port allocation scheme optimizes to satisfy one requirement at the expense of another. Therefore, these are soft requirements (SHOULD as opposed to MUST).


6. Deployment Considerations
6. 部署注意事项

Several issues are encountered when CGNs are used [RFC6269]. There is current work in the IETF toward alleviating some of these issues. For example, see [NAT-REVEAL].


7. Security Considerations
7. 安全考虑

If a malicious subscriber can spoof another subscriber's CPE, it may cause a DoS to that subscriber by creating mappings up to the allowed limit. An ISP can prevent this with ingress filtering, as described in [RFC2827].


This document recommends endpoint-independent filtering (EIF) as the default filtering behavior for CGNs. EIF has security considerations that are discussed in [RFC4787].


NATs sometimes perform fragment reassembly. CGNs would do so at presumably high data rates. Therefore, the reader should be familiar with the potential security issues described in [RFC4963].


8. Acknowledgements
8. 致谢

Thanks for the input and review by Alexey Melnikov, Arifumi Matsumoto, Barry Leiba, Benson Schliesser, Dai Kuwabara, Dan Wing, Dave Thaler, David Harrington, Francis Dupont, Jean-Francois Tremblay, Joe Touch, Lars Eggert, Kousuke Shishikura, Mohamed Boucadair, Martin Stiemerling, Meng Wei, Nejc Skoberne, Pete Resnick, Reinaldo Penno, Ron Bonica, Sam Hartman, Sean Turner, Senthil Sivakumar, Stephen Farrell, Stewart Bryant, Takanori Mizuguchi, Takeshi Tomochika, Tina Tsou, Tomohiro Fujisaki, Tomohiro Nishitani, Tomoya Yoshida, Wes George, Wesley Eddy, and Yasuhiro Shirasaki.

感谢Alexey Melnikov、Arifumi Matsumoto、Barry Leiba、Benson Schliesser、Dai Kuwabara、Dan Wing、Dave Thaler、David Harrington、Francis Dupont、Jean-Francois Tremblay、Joe Touch、Lars Eggert、Kousuke Shishikura、Mohamed Boucadair、Martin Stiemering、Meng Wei、Nejc Skoberne、Pete Resnick、Reinaldo Penno、Ron Bonica、,Sam Hartman、Sean Turner、Senthil Sivakumar、Stephen Farrell、Stewart Bryant、Takanori Mizuguchi、Takeshi Tomochika、Tina Tsou、藤崎智弘、西田智博、吉田智雅、乔治、艾迪和白崎安弘。

9. References
9. 工具书类
9.1. Normative References
9.1. 规范性引用文件

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.

[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。

[RFC4008] Rohit, R., Srisuresh, P., Raghunarayan, R., Pai, N., and C. Wang, "Definitions of Managed Objects for Network Address Translators (NAT)", RFC 4008, March 2005.

[RFC4008]Rohit,R.,Srisuresh,P.,Raghunarayan,R.,Pai,N.,和C.Wang,“网络地址转换器(NAT)管理对象的定义”,RFC 4008,2005年3月。

[RFC4787] Audet, F. and C. Jennings, "Network Address Translation (NAT) Behavioral Requirements for Unicast UDP", BCP 127, RFC 4787, January 2007.

[RFC4787]Audet,F.和C.Jennings,“单播UDP的网络地址转换(NAT)行为要求”,BCP 127,RFC 4787,2007年1月。

[RFC5382] Guha, S., Biswas, K., Ford, B., Sivakumar, S., and P. Srisuresh, "NAT Behavioral Requirements for TCP", BCP 142, RFC 5382, October 2008.

[RFC5382]Guha,S.,Biswas,K.,Ford,B.,Sivakumar,S.,和P.Srisuresh,“TCP的NAT行为要求”,BCP 142,RFC 5382,2008年10月。

[RFC5508] Srisuresh, P., Ford, B., Sivakumar, S., and S. Guha, "NAT Behavioral Requirements for ICMP", BCP 148, RFC 5508, April 2009.

[RFC5508]Srisuresh,P.,Ford,B.,Sivakumar,S.,和S.Guha,“ICMP的NAT行为要求”,BCP 148,RFC 5508,2009年4月。

[RFC5597] Denis-Courmont, R., "Network Address Translation (NAT) Behavioral Requirements for the Datagram Congestion Control Protocol", BCP 150, RFC 5597, September 2009.

[RFC5597]Denis Courmont,R.,“数据报拥塞控制协议的网络地址转换(NAT)行为要求”,BCP 150,RFC 5597,2009年9月。

[RFC6887] Wing, D., Ed., Cheshire, S., Boucadair, M., Penno, R., and P. Selkirk, "Port Control Protocol (PCP)", RFC 6887, April 2013.

[RFC6887]Wing,D.,Ed.,Cheshire,S.,Boucadair,M.,Penno,R.,和P.Selkirk,“港口控制协议(PCP)”,RFC 6887,2013年4月。

9.2. Informative Reference
9.2. 资料性参考

[RFC0793] Postel, J., "Transmission Control Protocol", STD 7, RFC 793, September 1981.

[RFC0793]Postel,J.,“传输控制协议”,标准7,RFC 793,1981年9月。

[RFC1122] Braden, R., "Requirements for Internet Hosts - Communication Layers", STD 3, RFC 1122, October 1989.

[RFC1122]Braden,R.,“互联网主机的要求-通信层”,标准3,RFC 1122,1989年10月。

[RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address Translator (NAT) Terminology and Considerations", RFC 2663, August 1999.

[RFC2663]Srisuresh,P.和M.Holdrege,“IP网络地址转换器(NAT)术语和注意事项”,RFC 2663,1999年8月。

[RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering: Defeating Denial of Service Attacks which employ IP Source Address Spoofing", BCP 38, RFC 2827, May 2000.

[RFC2827]Ferguson,P.和D.Senie,“网络入口过滤:击败利用IP源地址欺骗的拒绝服务攻击”,BCP 38,RFC 2827,2000年5月。

[RFC4963] Heffner, J., Mathis, M., and B. Chandler, "IPv4 Reassembly Errors at High Data Rates", RFC 4963, July 2007.

[RFC4963]Heffner,J.,Mathis,M.,和B.Chandler,“高数据速率下的IPv4重组错误”,RFC 4963,2007年7月。

[RFC5461] Gont, F., "TCP's Reaction to Soft Errors", RFC 5461, February 2009.

[RFC5461]Gont,F.,“TCP对软错误的反应”,RFC 54612009年2月。

[RFC6056] Larsen, M. and F. Gont, "Recommendations for Transport-Protocol Port Randomization", BCP 156, RFC 6056, January 2011.

[RFC6056]Larsen,M.和F.Gont,“传输协议端口随机化建议”,BCP 156,RFC 6056,2011年1月。

[RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful NAT64: Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers", RFC 6146, April 2011.

[RFC6146]Bagnulo,M.,Matthews,P.,和I.van Beijnum,“有状态NAT64:从IPv6客户端到IPv4服务器的网络地址和协议转换”,RFC 61462011年4月。

[RFC6264] Jiang, S., Guo, D., and B. Carpenter, "An Incremental Carrier-Grade NAT (CGN) for IPv6 Transition", RFC 6264, June 2011.

[RFC6264]Jiang,S.,Guo,D.,和B.Carpenter,“IPv6过渡的增量载波级NAT(CGN)”,RFC 62642011年6月。

[RFC6269] Ford, M., Boucadair, M., Durand, A., Levis, P., and P. Roberts, "Issues with IP Address Sharing", RFC 6269, June 2011.

[RFC6269]福特,M.,布卡达尔,M.,杜兰德,A.,利维斯,P.,和P.罗伯茨,“IP地址共享问题”,RFC 6269,2011年6月。

[RFC6302] Durand, A., Gashinsky, I., Lee, D., and S. Sheppard, "Logging Recommendations for Internet-Facing Servers", BCP 162, RFC 6302, June 2011.

[RFC6302]Durand,A.,Gashinsky,I.,Lee,D.,和S.Sheppard,“面向Internet服务器的日志记录建议”,BCP 162,RFC 6302,2011年6月。

[RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-Stack Lite Broadband Deployments Following IPv4 Exhaustion", RFC 6333, August 2011.

[RFC6333]Durand,A.,Droms,R.,Woodyatt,J.,和Y.Lee,“IPv4耗尽后的双栈Lite宽带部署”,RFC 63332011年8月。

[NAT-MIB] Perreault, S., Tsou, T., and S. Sivakumar, "Additional Managed Objects for Network Address Translators (NAT)", Work in Progress, February 2013.


[NAT-REVEAL] Boucadair, M., Touch, J., Levis, P., and R. Penno, "Analysis of Solution Candidates to Reveal a Host Identifier (HOST_ID) in Shared Address Deployments", Work in Progress, April 2013.


[NAT444] Donley, C., Ed., Howard, L., Kuarsingh, V., Berg, J., and J. Doshi, "Assessing the Impact of Carrier-Grade NAT on Network Applications", Work in Progress, April 2013.


[BITTORRENT] Boucadair, M., Zheng, T., Deng, X., and J. Queiroz, "Behavior of BitTorrent service in PCP-enabled networks with Address Sharing", Work in Progress, May 2012.


Authors' Addresses


Simon Perreault (editor) Viagenie 246 Aberdeen Quebec, QC G1R 2E1 Canada

Simon Perreault(编辑)加拿大魁北克省阿伯丁市Viagenie 246号QC G1R 2E1

   Phone: +1 418 656 9254
   Phone: +1 418 656 9254

Ikuhei Yamagata NTT Communications Corporation Gran Park Tower 17F, 3-4-1 Shibaura, Minato-ku Tokyo 108-8118 Japan

Ikuhei Yamagata NTT通信公司大公园大厦17楼,3-4-1 Shibaura,Minato ku东京108-8118

   Phone: +81 50 3812 4704
   Phone: +81 50 3812 4704

Shin Miyakawa NTT Communications Corporation Gran Park Tower 17F, 3-4-1 Shibaura, Minato-ku Tokyo 108-8118 Japan

新宫川NTT通信公司大公园大厦17楼,3-4-1 Shibaura,Minato ku东京108-8118

   Phone: +81 50 3812 4695
   Phone: +81 50 3812 4695

Akira Nakagawa Japan Internet Exchange Co., Ltd. (JPIX) Otemachi Building 21F, 1-8-1 Otemachi, Chiyoda-ku Tokyo 100-0004 Japan


   Phone: +81 90 9242 2717
   Phone: +81 90 9242 2717

Hiroyuki Ashida Cisco Systems Midtown Tower, 9-7-1, Akasaka Minato-Ku, Tokyo 107-6227 Japan

Hiroyuki Ashida Cisco Systems Midtown Tower,9-7-1,Akasaka Minato Ku,东京107-6227