Network Working Group V. Manral
Request for Comments: 4063 SiNett Corp.
Category: Informational R. White
Cisco Systems
A. Shaikh
AT&T Labs (Research)
April 2005
Network Working Group V. Manral
Request for Comments: 4063 SiNett Corp.
Category: Informational R. White
Cisco Systems
A. Shaikh
AT&T Labs (Research)
April 2005
Considerations When Using Basic OSPF Convergence Benchmarks
使用基本OSPF收敛基准时的注意事项
Status of This Memo
关于下段备忘
This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
本备忘录为互联网社区提供信息。它没有规定任何类型的互联网标准。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (C) The Internet Society (2005).
版权所有（C）互联网协会（2005年）。
Abstract
摘要
This document discusses the applicability of various tests for measuring single router control plane convergence, specifically in regard to the Open Shortest First (OSPF) protocol. There are two general sections in this document, the first discusses advantages and limitations of specific OSPF convergence tests, and the second discusses more general pitfalls to be considered when routing protocol convergence is tested.
本文讨论了测量单路由器控制平面收敛性的各种测试的适用性，特别是关于开放最短优先（OSPF）协议。本文档中有两个一般部分，第一部分讨论特定OSPF收敛测试的优点和局限性，第二部分讨论测试路由协议收敛时要考虑的更一般的陷阱。
There is a growing interest in testing single router control plane convergence for routing protocols, and many people are looking at testing methodologies that can provide information on how long it takes for a network to converge after various network events occur. It is important to consider the framework within which any given convergence test is executed when one attempts to apply the results of the testing, since the framework can have a major impact on the results. For instance, determining when a network is converged, what parts of the router's operation are considered within the testing, and other such things will have a major impact on the apparent performance that routing protocols provide.
人们对路由协议的单路由器控制平面收敛性的测试越来越感兴趣，许多人正在研究能够提供各种网络事件发生后网络收敛所需时间信息的测试方法。重要的是考虑一个框架内的任何给定的收敛测试执行时，一个人试图应用测试的结果，因为框架可以有重大影响的结果。例如，确定网络何时聚合、测试中考虑了路由器操作的哪些部分，以及其他此类事项将对路由协议提供的明显性能产生重大影响。
This document describes in detail various benefits and pitfalls of tests described in [BENCHMARK]. It also explains how such measurements can be useful for providers and the research community.
本文档详细描述了[BENCHMARK]中描述的测试的各种优点和缺点。它还解释了这些测量如何对提供者和研究社区有用。
NOTE: In this document, the word "convergence" refers to single router control plane convergence [TERM].
注：在本文件中，“收敛”一词指单路由器控制平面收敛[术语]。
o To be able to compare the iterations of a protocol implementation. It is often useful to be able to compare the performance of two iterations of a given implementation of a protocol in order to determine where improvements have been made and where further improvements can be made.
o 能够比较协议实现的迭代。能够比较一个协议的给定实现的两次迭代的性能通常是有用的，以便确定在哪些方面进行了改进以及在哪些方面可以进一步改进。
o To understand, given a set of parameters (network conditions), how a particular implementation on a particular device will perform. For instance, if you were trying to decide the processing power (size of device) required in a certain location within a network, you could emulate the conditions that will exist at that point in the network and use the test described to measure the performance of several different routers. The results of these tests can provide one possible data point for an intelligent decision.
o 为了理解，给定一组参数（网络条件），特定设备上的特定实现将如何执行。例如，如果您试图确定网络中某个位置所需的处理能力（设备大小），则可以模拟网络中该点存在的条件，并使用描述的测试来测量多个不同路由器的性能。这些测试的结果可以为智能决策提供一个可能的数据点。
If the device being tested is to be deployed in a running network, using routes taken from the network where the equipment is to be deployed rather than some generated topology in these tests will yield results that are closer to the real performance of the device. Care should be taken to emulate or take routes from the actual location in the network where the device will be (or would be) deployed. For instance, one set of routes may be taken from an ABR, one set from an area 0 only router, various sets from stub area, another set from various normal areas, etc.
如果要在正在运行的网络中部署正在测试的设备，则在这些测试中使用从要部署设备的网络中获取的路由，而不是使用生成的拓扑，将产生更接近设备实际性能的结果。应注意模拟或从将（或将）部署设备的网络中的实际位置获取路由。例如，一组路由可取自ABR，一组路由取自仅区域0路由器，各种路由取自存根区域，另一组路由取自各种正常区域，等等。
o To measure the performance of an OSPF implementation in a wide variety of scenarios.
o 衡量OSPF实施在各种场景中的性能。
o To be used as parameters in OSPF simulations by researchers. It may sometimes be required for certain kinds of research to measure the individual delays of each parameter within an OSPF implementation. These delays can be measured using the methods defined in [BENCHMARK].
o 供研究人员在OSPF模拟中用作参数。有时，某些类型的研究可能需要测量OSPF实现中每个参数的个别延迟。可以使用[BENCHMARK]中定义的方法测量这些延迟。
o To help optimize certain configurable parameters. It may sometimes be helpful for operators to know the delay required for individual tasks in order to optimize the resource usage in the network. For example, if the processing time on a router is
o 帮助优化某些可配置参数。为了优化网络中的资源使用，操作员有时可以了解单个任务所需的延迟。例如，如果路由器上的处理时间为
found to be x seconds, determining the rate at which to flood LSAs to that router would be helpful so as not to overload the network.
如果发现是x秒，则确定将LSA洪泛到该路由器的速率将有助于避免网络过载。
o The interactions of convergence and forwarding; testing is restricted to events occurring within the control plane. Forwarding performance is the primary focus in [INTERCONNECT], and it is expected to be dealt with in work that ensues from [FIB-TERM].
o 融合与转发的互动；测试仅限于控制平面内发生的事件。转发性能是[INTERCONNECT]的主要关注点，预计将在[FIB-TERM]后续的工作中处理。
o Duplicate LSAs are Acknowledged Immediately. A few tests rely on the property that duplicate LSA Acknowledgements are not delayed but are done immediately. However, if an implementation does not acknowledge duplicate LSAs immediately on receipt, the testing methods presented in [BENCHMARK] could give inaccurate measurements.
o 立即确认重复的LSA。一些测试依赖于这样的属性：重复的LSA确认不会延迟，而是立即完成。但是，如果一个实现没有在收到重复的LSA后立即确认，那么[BENCHMARK]中介绍的测试方法可能会给出不准确的测量结果。
o It is assumed that SPF is non-preemptive. If SPF is implemented so that it can (and will be) preempted, the SPF measurements taken in [BENCHMARK] would include the times that the SPF process is not running, thus giving inaccurate measurements. ([BENCHMARK] measures the total time taken for SPF to run, not the amount of time that SPF actually spends on the device's processor.)
o 假设SPF是非抢占的。如果SPF的实现使其能够（并且将被）抢占，则在[BENCHMARK]中进行的SPF测量将包括SPF进程未运行的时间，从而给出不准确的测量。（[BENCHMARK]测量SPF运行所需的总时间，而不是SPF在设备处理器上实际花费的时间。）
o Some implementations may be multithreaded or use a multiprocess/multirouter model of OSPF. If because of this any of the assumptions made during measurement are violated in such a model, measurements could be inaccurate.
o 一些实现可能是多线程的，或者使用OSPF的多进程/多路由器模型。因此，如果在这种模型中违反了测量过程中的任何假设，则测量可能不准确。
o The measurements resulting from the tests in [BENCHMARK] may not provide the information required to deploy a device in a large-scale network. The tests described focus on individual components of an OSPF implementation's performance, and it may be difficult to combine the measurements in a way that accurately depicts a device's performance in a large-scale network. Further research is required in this area.
o [BENCHMARK]中的测试结果可能无法提供在大规模网络中部署设备所需的信息。所描述的测试侧重于OSPF实现性能的各个组件，并且可能很难以准确描述大规模网络中设备性能的方式组合测量结果。这方面还需要进一步研究。
o The measurements described in [BENCHMARK] should be used with great care when comparing two different implementations of OSPF from two different vendors. For instance, there are many other factors than convergence speed that need to be taken into consideration when comparing different vendors' products. One difficulty is aligning the resources available on one device to the resources available on another.
o 在比较来自两个不同供应商的OSPF的两种不同实现时，应非常小心地使用[BENCHMARK]中描述的度量。例如，在比较不同供应商的产品时，除了收敛速度之外，还有许多其他因素需要考虑。一个困难是将一台设备上的可用资源与另一台设备上的可用资源进行对齐。
Some observations recorded while implementing the tests described in [BENCHMARK] are noted in this section.
在执行[基准测试]中描述的测试时记录的一些观察结果在本节中进行了说明。
The most difficult test to perform is the external measurement of the time required to perform an SPF calculation because the amount of time between the first LSA that indicates a topology change and the duplicate LSA is critical. If the duplicate LSA is sent too quickly, it may be received before the device being tested actually begins running SPF on the network change information. If the delay between the two LSAs is too long, the device may finish SPF processing before receiving the duplicate LSA. It is important to closely investigate any delays between the receipt of an LSA and the beginning of an SPF calculation in the tested device; multiple tests with various delays might be required to determine what delay needs to be used to measure the SPF calculation time accurately.
最难执行的测试是执行SPF计算所需时间的外部测量，因为指示拓扑变化的第一个LSA和重复LSA之间的时间量至关重要。如果发送重复LSA的速度过快，则可能会在被测试设备实际开始在网络更改信息上运行SPF之前收到该LSA。如果两个LSA之间的延迟太长，设备可能会在接收重复LSA之前完成SPF处理。密切调查受试设备接收LSA和开始SPF计算之间的任何延迟非常重要；可能需要进行多次不同延迟的测试，以确定需要使用何种延迟来准确测量SPF计算时间。
Some implementations may force two intervals, the SPF hold time and the SPF delay, between successive SPF calculations. If an SPF hold time exists, it should be subtracted from the total SPF execution time. If an SPF delay exists, it should be noted in the test results.
一些实现可能会在连续的SPF计算之间强制两个间隔，即SPF保持时间和SPF延迟。如果存在SPF保持时间，则应从总SPF执行时间中减去该时间。如果存在SPF延迟，则应在测试结果中注明。
The device on which measurements are taken (not the device being tested) also adds noise to the test results, primarily in the form of delay in packet processing and measurement output. The largest source of noise is generally the delay between the receipt of packets by the measuring device and the receipt of information about the packet by the device's output, where the event can be measured. The following steps may be taken to reduce this sampling noise:
在其上进行测量的设备（不是被测设备）也会给测试结果增加噪声，主要表现为数据包处理和测量输出的延迟。最大的噪声源通常是测量设备接收数据包与设备输出接收数据包相关信息之间的延迟，在此情况下可测量事件。可以采取以下步骤来降低该采样噪声：
o Increasing the number of samples taken will generally improve the tester's ability to determine what is noise, and to remove it from the results. This applies to the DUT as well.
o 增加采集的样本数量通常会提高测试人员确定什么是噪声以及从结果中去除噪声的能力。这也适用于DUT。
o Try to take time-stamp for a packet as early as possible. Depending on the operating system being used on the box, one can instrument the kernel to take the time-stamp when the interrupt is processed. This does not eliminate the noise completely, but at least reduces it.
o 尽可能早地为数据包设置时间戳。根据盒子上使用的操作系统，可以在处理中断时对内核进行指示，以获取时间戳。这并不能完全消除噪声，但至少可以降低噪声。
o Keep the measurement box as lightly loaded as possible. This applies to the DUT as well.
o 使测量箱尽可能轻载。这也适用于DUT。
o Having an estimate of noise can also be useful.
o 对噪声进行估计也很有用。
The DUT also adds noise to the measurement.
DUT还增加了测量噪声。
4.3. Gaining an Understanding of the Implementation Improves Measurements
4.3. 了解实现可以改进度量
Although the tester will (generally) not have access to internal information about the OSPF implementation being tested using [BENCHMARK], the more thorough the tester's knowledge of the implementation is, the more accurate the results of the tests will be. For instance, in some implementations, the installation of routes in local routing tables may occur while the SPF is being calculated, dramatically impacting the time required to calculate the SPF.
尽管测试人员（通常）无法访问有关使用[基准]测试的OSPF实现的内部信息，但测试人员对实现的了解越透彻，测试结果就越准确。例如，在某些实现中，在计算SPF时可能会在本地路由表中安装路由，这会显著影响计算SPF所需的时间。
One method that can be used to become familiar with the tests described in [BENCHMARK] is to perform the tests on an OSPF implementation for which all the internal details are available. Although there is no assurance that any two implementations will be similar, this will provide a better understanding of the tests themselves.
一种可以用来熟悉[BENCHMARK]中描述的测试的方法是在OSPF实现上执行测试，所有内部细节都可用。虽然不能保证任何两个实现都是相似的，但这将更好地理解测试本身。
In many OSPF benchmark tests, a generator injecting a number of LSAs is called for. There are several areas in which injected LSAs can be varied in testing:
在许多OSPF基准测试中，需要一个注入大量LSA的生成器。在测试过程中，注入的LSA可以在几个方面发生变化：
o The number of destinations represented by the injected LSAs
o 由注入的LSA表示的目的地数
Each destination represents a single reachable IP network; these will be leaf nodes on the shortest path tree. The primary impact to performance should be the time required to insert destinations in the local routing table and handling the memory required to store the data.
每个目的地代表单个可到达的IP网络；这些将是最短路径树上的叶节点。对性能的主要影响应该是在本地路由表中插入目的地和处理存储数据所需的内存所需的时间。
o The types of LSAs injected
o 注入LSA的类型
There are several types of LSAs that would be acceptable under different situations; within an area, for instance, types 1, 2, 3, 4, and 5 are likely to be received by a router. Within a not-so-stubby area, however, type-7 LSAs would replace the type-5 LSAs received. These sorts of characterizations are important to note in any test results.
在不同的情况下，有几种类型的LSA是可以接受的；例如，在一个区域内，类型1、2、3、4和5可能由路由器接收。然而，在一个不那么短的区域内，7型LSA将取代收到的5型LSA。在任何测试结果中，必须注意这些类型的特征。
o The number of LSAs injected
o 注入的LSA数
Within any injected set of information, the number of each type of LSA injected is also important. This will impact the shortest path algorithm's ability to handle large numbers of nodes, large shortest path first trees, etc.
在任何注入的信息集中，注入的每种LSA的数量也很重要。这将影响最短路径算法处理大量节点、大型最短路径优先树等的能力。
o The order of LSA injection
o LSA注射顺序
The order in which LSAs are injected should not favor any given data structure used for storing the LSA database on the device being tested. For instance, AS-External LSAs have AS wide flooding scope; any type-5 LSA originated is immediately flooded to all neighbors. However, the type-4 LSA, which announces the ASBR as a border router, is originated in an area at SPF time (by ABRs on the edge of the area in which the ASBR is). If SPF isn't scheduled immediately on the ABRs originating the type-4 LSA, the type-4 LSA is sent after the type-5 LSA's reach a router in the adjacent area. Therefore, routes to the external destinations aren't immediately added to the routers in the other areas. When the routers that already have the type 5s receive the type-4 LSA, all the external routes are added to the tree at the same time. This timing could produce different results than a router receiving a type 4 indicating the presence of a border router, followed by the type 5s originated by that border router.
LSA的注入顺序不应偏向于用于在被测设备上存储LSA数据库的任何给定数据结构。例如，由于外部LSA具有同样宽的泛洪范围；任何源于5型LSA的设备都会立即被洪水淹没到所有邻居。然而，宣布ASBR为边界路由器的4型LSA在SPF时间（由ASBR所在区域边缘上的ABR）起源于某个区域。如果SPF没有立即在发起4型LSA的ABR上调度，则在5型LSA到达相邻区域的路由器后发送4型LSA。因此，到外部目的地的路由不会立即添加到其他区域的路由器。当已经具有5s类型的路由器接收到4类型LSA时，所有外部路由将同时添加到树中。这种定时可能会产生不同的结果，不同于路由器接收到表示存在边界路由器的类型4，然后是该边界路由器发起的类型5。
The ordering can be changed in various tests to provide insight into the efficiency of storage within the DUT. Any such changes in ordering should be noted in test results.
可以在各种测试中更改顺序，以便深入了解DUT内的存储效率。应在试验结果中注明订购中的任何此类变化。
The complexity of Dijkstra's algorithm depends on the data structure used for storing vertices with their current minimum distances from the source; the simplest structure is a list of vertices currently reachable from the source. In a simple list of vertices, finding the minimum cost vertex would then take O(size of the list). There will be O(n) such operations if we assume that all the vertices are ultimately reachable from the source. Moreover, after the vertex with minimum cost is found, the algorithm iterates through all the edges of the vertex and updates the cost of other vertices. With an adjacency list representation, this step, when iterated over all the vertices, would take O(E) time, with E being the number of edges in the graph. Thus, the overall running time is:
Dijkstra算法的复杂性取决于用于存储顶点的数据结构，这些顶点与源的当前最小距离；最简单的结构是当前可从源访问的顶点列表。在一个简单的顶点列表中，找到最小代价顶点需要O（列表的大小）。如果我们假设所有顶点最终都可以从源到达，那么将有O（n）个这样的操作。此外，在找到代价最小的顶点后，该算法迭代遍历顶点的所有边，并更新其他顶点的代价。对于邻接列表表示，当迭代所有顶点时，此步骤将花费O（E）时间，E是图中的边数。因此，总运行时间为：
O(sum(i:1, n)(size(list at level i) + E).
O（总和（i:1，n）（大小（第一级列表）+E）。
So everything boils down to the size(list at level i).
因此，一切都归结为规模（第一级列表）。
If the graph is linear,
如果图形是线性的，
root
|
1
|
2
|
3
|
4
|
5
|
6
root
|
1
|
2
|
3
|
4
|
5
|
6
and source is a vertex on the end, then size(list at level i) = 1 for all i. Moreover, E = n - 1. Therefore, running time is O(n).
源是末端的一个顶点，然后所有i的大小（级别i的列表）=1。此外，E=n-1。因此，运行时间为O（n）。
If the graph is a balanced binary tree,
如果图是平衡二叉树，
root
/ \
1 2
/ \ / \
3 4 5 6
root
/ \
1 2
/ \ / \
3 4 5 6
size(list at level i) is a little complicated. First, it increases by 1 at each level up to a certain number, and then it goes down by 1. If we assume that the tree is a complete tree (as shown above) with k levels (1 to k), then size(list) goes on like this: 1, 2, 3,
规模（第一级列表）有点复杂。首先，它在每个级别上增加1，直到某个数字，然后下降1。如果我们假设树是一个完整的树（如上所示），有k个级别（1到k），那么大小（列表）是这样的：1，2，3，
Then the number of edges E is still n - 1. It then turns out that the run-time is O(n^2) for such a tree.
那么边的数目E仍然是n-1。然后，对于这样的树，运行时间是O（n^2）。
If the graph is a complete graph (fully-connected mesh), then size(list at level i) = n - i. Number of edges E = O(n^2). Therefore, run-time is O(n^2).
如果图形是一个完整的图形（完全连接的网格），那么大小（在级别i处列出）=n-i。边数E=O（n^2）。因此，运行时为O（n^2）。
Therefore, the performance of the shortest path first algorithm used to compute the best paths through the network is dependent on the construction of the tree. The best practice would be to try to make any emulated network look as much like a real network as possible, especially in the area of the tree depth, the meshiness of the
因此，用于计算通过网络的最佳路径的最短路径优先算法的性能取决于树的构造。最好的做法是尽量使任何模拟网络看起来尽可能像真实网络，特别是在树的深度、网络的网状度方面
network, the number of stub links versus transit links, and the number of connections and nodes to process at each level within the original tree.
网络、存根链接与传输链接的数量，以及原始树中每一级要处理的连接和节点的数量。
As the size of networks grows, it becomes more and more difficult to actually create a large-scale network on which to test the properties of routing protocols and their implementations. In general, network emulators are used to provide emulated topologies that can be advertised to a device with varying conditions. Route generators tend to be either a specialized device, a piece of software which runs on a router, or a process that runs on another operating system, such as Linux or another variant of Unix.
随着网络规模的增长，实际创建大规模网络以测试路由协议及其实现的属性变得越来越困难。通常，网络仿真器用于提供可在不同条件下向设备公布的仿真拓扑。路由生成器通常是一个专用设备、一个在路由器上运行的软件，或者是一个在另一个操作系统（如Linux或Unix的另一个变体）上运行的进程。
Some of the characteristics of this device should be as follows:
该装置的某些特性应如下所示：
o The ability to connect to several devices using both point-to-point and broadcast high-speed media. Point-to-point links can be emulated with high-speed Ethernet as long as there is no hub or other device between the DUT and the route generator, and the link is configured as a point-to-point link within OSPF [BROADCAST-P2P].
o 使用点对点和广播高速媒体连接到多个设备的能力。只要DUT和路由生成器之间没有集线器或其他设备，并且链路被配置为OSPF[BROADCAST-P2P]内的点对点链路，就可以用高速以太网模拟点对点链路。
o The ability to create a set of LSAs that appear to be a logical, realistic topology. For instance, the generator should be able to mix the number of point-to-point and broadcast links within the emulated topology and to inject varying numbers of externally reachable destinations.
o 能够创建一组逻辑、真实拓扑的LSA。例如，生成器应该能够在模拟拓扑中混合点到点和广播链路的数量，并注入不同数量的外部可到达目的地。
o The ability to withdraw and add routing information into and from the emulated topology to emulate flapping links.
o 在模拟拓扑中提取和添加路由信息以模拟摆动链接的能力。
o The ability to randomly order the LSAs representing the emulated topology as they are advertised.
o 能够在发布时对表示仿真拓扑的LSA进行随机排序。
o The ability to log or otherwise measure the time between packets transmitted and received.
o 记录或以其他方式测量发送和接收数据包之间的时间的能力。
o The ability to change the rate at which OSPF LSAs are transmitted.
o 改变OSPF LSA传输速率的能力。
o The generator and the collector should be fast enough that they are not bottlenecks. The devices should also have a degree of granularity of measurement at least as small as is desired from the test results.
o 生成器和收集器的速度应足够快，以免出现瓶颈。设备的测量粒度也应至少与测试结果所需的粒度一样小。
This document does not modify the underlying security considerations in [OSPF].
本文档不修改[OSPF]中的基本安全注意事项。
Thanks to Howard Berkowitz (hcb@clark.net) and the rest of the BGP benchmarking team for their support and to Kevin Dubray (kdubray@juniper.net), who realized the need for this document.
多亏了霍华德·伯克维茨(hcb@clark.net)以及BGP基准测试团队的其他成员，感谢他们的支持和Kevin Dubrey(kdubray@juniper.net)，他意识到需要这份文件。
[BENCHMARK] Manral, V., White, R., and A. Shaikh, "Benchmarking Basic OSPF Single Router Control Plane Convergence", RFC 4061, April 2005.
[基准测试]Manral，V.，White，R.，和A.Shaikh，“基准测试基本OSPF单路由器控制平面收敛”，RFC 4061，2005年4月。
[TERM] Manral, V., White, R., and A. Shaikh, "OSPF Benchmarking Terminology and Concepts", RFC 4062, April 2005.
[术语]Manral，V.，White，R.，和A.Shaikh，“OSPF基准术语和概念”，RFC 4062，2005年4月。
[OSPF] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[OSPF]Moy，J.，“OSPF版本2”，STD 54，RFC 23281998年4月。
[INTERCONNECT] Bradner, S. and J. McQuaid, "Benchmarking Methodology for Network Interconnect Devices", RFC 2544, March 1999.
[互连]Bradner，S.和J.McQuaid，“网络互连设备的基准测试方法”，RFC 2544，1999年3月。
[FIB-TERM] Trotter, G., "Terminology for Forwarding Information Base (FIB) based Router Performance", RFC 3222, December 2001.
[FIB-TERM]Trotter，G.“基于转发信息库（FIB）的路由器性能术语”，RFC3222，2001年12月。
[BROADCAST-P2P] Shen, Naiming, et al., "Point-to-point operation over LAN in link-state routing protocols", Work in Progress, August, 2003.
[BROADCAST-P2P]沈乃明，等，“链路状态路由协议下局域网上的点对点操作”，正在进行的工作，2003年8月。
Authors' Addresses
作者地址
Vishwas Manral SiNett Corp, Ground Floor, Embassy Icon Annexe, 2/1, Infantry Road, Bangalore, India
印度班加罗尔步兵路2/1号大使馆图标附件一楼Vishwas Manral SiNett公司
EMail: vishwas@sinett.com
EMail: vishwas@sinett.com
Russ White Cisco Systems, Inc. 7025 Kit Creek Rd. Research Triangle Park, NC 27709
Russ White Cisco Systems，Inc.地址：北卡罗来纳州三角研究公园Kit Creek路7025号，邮编：27709
EMail: riw@cisco.com
EMail: riw@cisco.com
Aman Shaikh AT&T Labs (Research) 180 Park Av, PO Box 971 Florham Park, NJ 07932
Aman Shaikh AT&T实验室（研究）180 Park Av，邮政信箱971 Florham Park，NJ 07932
EMail: ashaikh@research.att.com
EMail: ashaikh@research.att.com
Full Copyright Statement
完整版权声明
Copyright (C) The Internet Society (2005).
版权所有（C）互联网协会（2005年）。
This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights.
本文件受BCP 78中包含的权利、许可和限制的约束，除其中规定外，作者保留其所有权利。
This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
本文件及其包含的信息是按“原样”提供的，贡献者、他/她所代表或赞助的组织（如有）、互联网协会和互联网工程任务组不承担任何明示或暗示的担保，包括但不限于任何保证，即使用本文中的信息不会侵犯任何权利，或对适销性或特定用途适用性的任何默示保证。
Intellectual Property
知识产权
The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79.
IETF对可能声称与本文件所述技术的实施或使用有关的任何知识产权或其他权利的有效性或范围，或此类权利下的任何许可可能或可能不可用的程度，不采取任何立场；它也不表示它已作出任何独立努力来确定任何此类权利。有关RFC文件中权利的程序信息，请参见BCP 78和BCP 79。
Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr.
向IETF秘书处披露的知识产权副本和任何许可证保证，或本规范实施者或用户试图获得使用此类专有权利的一般许可证或许可的结果，可从IETF在线知识产权存储库获取，网址为http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org.
IETF邀请任何相关方提请其注意任何版权、专利或专利申请，或其他可能涵盖实施本标准所需技术的专有权利。请将信息发送至IETF的IETF-ipr@ietf.org.
Acknowledgement
确认
Funding for the RFC Editor function is currently provided by the Internet Society.
RFC编辑功能的资金目前由互联网协会提供。