Network Working Group S. Corson
Request for Comments: 2501 University of Maryland
Category: Informational J. Macker
Naval Research Laboratory
January 1999
Network Working Group S. Corson
Request for Comments: 2501 University of Maryland
Category: Informational J. Macker
Naval Research Laboratory
January 1999
Mobile Ad hoc Networking (MANET): Routing Protocol Performance Issues and Evaluation Considerations
移动自组网（MANET）：路由协议性能问题和评估考虑
Status of this Memo
本备忘录的状况
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 (1999). All Rights Reserved.
版权所有（C）互联网协会（1999年）。版权所有。
Abstract
摘要
This memo first describes the characteristics of Mobile Ad hoc Networks (MANETs), and their idiosyncrasies with respect to traditional, hardwired packet networks. It then discusses the effect these differences have on the design and evaluation of network control protocols with an emphasis on routing performance evaluation considerations.
本备忘录首先描述了移动自组织网络（MANET）的特点，以及它们相对于传统硬连线分组网络的特性。然后讨论了这些差异对网络控制协议设计和评估的影响，重点讨论了路由性能评估的考虑因素。
With recent performance advancements in computer and wireless communications technologies, advanced mobile wireless computing is expected to see increasingly widespread use and application, much of which will involve the use of the Internet Protocol (IP) suite. The vision of mobile ad hoc networking is to support robust and efficient operation in mobile wireless networks by incorporating routing functionality into mobile nodes. Such networks are envisioned to have dynamic, sometimes rapidly-changing, random, multihop topologies which are likely composed of relatively bandwidth-constrained wireless links.
随着计算机和无线通信技术最近的性能提升，高级移动无线计算预计将得到越来越广泛的使用和应用，其中大部分将涉及互联网协议（IP）套件的使用。移动adhoc网络的愿景是通过将路由功能整合到移动节点中，支持移动无线网络中稳健而高效的运行。这样的网络被设想为具有动态的、有时快速变化的、随机的多跳拓扑，这些拓扑可能由相对带宽受限的无线链路组成。
Within the Internet community, routing support for mobile hosts is presently being formulated as "mobile IP" technology. This is a technology to support nomadic host "roaming", where a roaming host may be connected through various means to the Internet other than its well known fixed-address domain space. The host may be directly physically connected to the fixed network on a foreign subnet, or be
在互联网社区内，对移动主机的路由支持目前被定义为“移动IP”技术。这是一种支持游牧主机“漫游”的技术，其中漫游主机可以通过各种方式连接到互联网，而不是其众所周知的固定地址域空间。主机可以直接物理连接到外部子网上的固定网络，或者
connected via a wireless link, dial-up line, etc. Supporting this form of host mobility (or nomadicity) requires address management, protocol interoperability enhancements and the like, but core network functions such as hop-by-hop routing still presently rely upon pre-existing routing protocols operating within the fixed network. In contrast, the goal of mobile ad hoc networking is to extend mobility into the realm of autonomous, mobile, wireless domains, where a set of nodes--which may be combined routers and hosts--themselves form the network routing infrastructure in an ad hoc fashion.
通过无线链路、拨号线等连接。支持这种形式的主机移动性（或游牧性）需要地址管理、协议互操作性增强等，但核心网络功能（如逐跳路由）目前仍依赖于在固定网络中运行的现有路由协议。相比之下，移动自组织网络的目标是将移动性扩展到自治、移动、无线领域，其中一组节点（可能是路由器和主机的组合）本身以自组织方式形成网络路由基础设施。
The technology of Mobile Ad hoc Networking is somewhat synonymous with Mobile Packet Radio Networking (a term coined via during early military research in the 70's and 80's), Mobile Mesh Networking (a term that appeared in an article in The Economist regarding the structure of future military networks) and Mobile, Multihop, Wireless Networking (perhaps the most accurate term, although a bit cumbersome).
移动自组织网络技术在某种程度上与移动分组无线网络（70年代和80年代早期军事研究期间创造的术语）、移动网状网络（出现在《经济学人》关于未来军事网络结构的文章中的术语）和移动、多跳、无线网络同义（也许是最准确的术语，尽管有点麻烦）。
There is current and future need for dynamic ad hoc networking technology. The emerging field of mobile and nomadic computing, with its current emphasis on mobile IP operation, should gradually broaden and require highly-adaptive mobile networking technology to effectively manage multihop, ad hoc network clusters which can operate autonomously or, more than likely, be attached at some point(s) to the fixed Internet.
目前和未来都需要动态adhoc网络技术。移动和游牧计算的新兴领域，当前的重点是移动IP操作，应该逐渐扩大并需要高度自适应的移动网络技术，以有效地管理多跳、自组织网络集群，这些集群可以自主操作，或者很可能在某个点连接到固定互联网。
Some applications of MANET technology could include industrial and commercial applications involving cooperative mobile data exchange. In addition, mesh-based mobile networks can be operated as robust, inexpensive alternatives or enhancements to cell-based mobile network infrastructures. There are also existing and future military networking requirements for robust, IP-compliant data services within mobile wireless communication networks [1]--many of these networks consist of highly-dynamic autonomous topology segments. Also, the developing technologies of "wearable" computing and communications may provide applications for MANET technology. When properly combined with satellite-based information delivery, MANET technology can provide an extremely flexible method for establishing communications for fire/safety/rescue operations or other scenarios requiring rapidly-deployable communications with survivable, efficient dynamic networking. There are likely other applications for MANET technology which are not presently realized or envisioned by the authors. It is, simply put, improved IP-based networking technology for dynamic, autonomous wireless networks.
MANET技术的一些应用可能包括涉及合作移动数据交换的工业和商业应用。此外，基于mesh的移动网络可以作为基于小区的移动网络基础设施的健壮、廉价的替代方案或增强功能来运行。在移动无线通信网络[1]中，对健壮的、符合IP的数据服务也存在现有和未来的军事网络需求——其中许多网络由高度动态的自治拓扑段组成。此外，“可穿戴”计算和通信技术的发展可能为MANET技术提供应用。如果将MANET技术与基于卫星的信息传输适当结合，MANET技术可以提供一种极为灵活的方法，用于为火灾/安全/救援行动或其他需要快速部署通信的场景建立通信，并提供可生存、高效的动态网络。MANET技术可能还有其他应用，但作者目前尚未实现或设想。简单地说，它是一种改进的基于IP的网络技术，用于动态、自治的无线网络。
A MANET consists of mobile platforms (e.g., a router with multiple hosts and wireless communications devices)--herein simply referred to as "nodes"--which are free to move about arbitrarily. The nodes may be located in or on airplanes, ships, trucks, cars, perhaps even on people or very small devices, and there may be multiple hosts per router. A MANET is an autonomous system of mobile nodes. The system may operate in isolation, or may have gateways to and interface with a fixed network. In the latter operational mode, it is typically envisioned to operate as a "stub" network connecting to a fixed internetwork. Stub networks carry traffic originating at and/or destined for internal nodes, but do not permit exogenous traffic to "transit" through the stub network.
MANET由移动平台（例如，具有多个主机和无线通信设备的路由器）组成，此处简称为“节点”，可自由移动。节点可能位于飞机、轮船、卡车、汽车上，甚至可能位于人或非常小的设备上，每个路由器可能有多个主机。MANET是一个由移动节点组成的自治系统。该系统可以隔离运行，也可以具有与固定网络连接的网关。在后一种操作模式中，它通常被设想为连接到固定互联网的“存根”网络。存根网络承载源自和/或目的地为内部节点的流量，但不允许外部流量通过存根网络“传输”。
MANET nodes are equipped with wireless transmitters and receivers using antennas which may be omnidirectional (broadcast), highly-directional (point-to-point), possibly steerable, or some combination thereof. At a given point in time, depending on the nodes' positions and their transmitter and receiver coverage patterns, transmission power levels and co-channel interference levels, a wireless connectivity in the form of a random, multihop graph or "ad hoc" network exists between the nodes. This ad hoc topology may change with time as the nodes move or adjust their transmission and reception parameters.
MANET节点配备有使用天线的无线发射机和接收机，这些天线可以是全向（广播）、高度定向（点到点）、可能是可操纵的，或者是它们的一些组合。在给定的时间点，根据节点的位置及其发射机和接收机覆盖模式、发射功率水平和同信道干扰水平，节点之间存在以随机、多跳图或“自组织”网络形式存在的无线连接。当节点移动或调整其传输和接收参数时，该自组织拓扑可能随时间而改变。
MANETs have several salient characteristics:
移动自组网有几个显著特点：
1) Dynamic topologies: Nodes are free to move arbitrarily; thus, the network topology--which is typically multihop--may change randomly and rapidly at unpredictable times, and may consist of both bidirectional and unidirectional links.
1) 动态拓扑：节点可以自由移动；因此，网络拓扑（通常为多跳）可能在不可预测的时间内随机快速变化，并且可能由双向和单向链路组成。
2) Bandwidth-constrained, variable capacity links: Wireless links will continue to have significantly lower capacity than their hardwired counterparts. In addition, the realized throughput of wireless communications--after accounting for the effects of multiple access, fading, noise, and interference conditions, etc.--is often much less than a radio's maximum transmission rate.
2) 带宽受限的可变容量链路：无线链路的容量将继续显著低于硬连线链路。此外，在考虑多址、衰落、噪声和干扰条件等影响后，无线通信的实际吞吐量通常远低于无线电的最大传输速率。
One effect of the relatively low to moderate link capacities is that congestion is typically the norm rather than the exception, i.e. aggregate application demand will likely approach or exceed network capacity frequently. As the mobile network is often simply an extension of the fixed network infrastructure, mobile ad hoc users will demand similar services. These demands will continue to increase as multimedia computing and collaborative networking applications rise.
相对较低至中等链路容量的一个影响是，拥塞通常是常态而不是例外，即总应用需求可能会经常接近或超过网络容量。由于移动网络通常只是固定网络基础设施的扩展，移动adhoc用户将需要类似的服务。随着多媒体计算和协作网络应用的增加，这些需求将继续增加。
3) Energy-constrained operation: Some or all of the nodes in a MANET may rely on batteries or other exhaustible means for their energy. For these nodes, the most important system design criteria for optimization may be energy conservation.
3) 能量受限操作：MANET中的部分或所有节点可能依赖电池或其他可耗尽的方式获取能量。对于这些节点，优化的最重要系统设计标准可能是节能。
4) Limited physical security: Mobile wireless networks are generally more prone to physical security threats than are fixed-cable nets. The increased possibility of eavesdropping, spoofing, and denial-of-service attacks should be carefully considered. Existing link security techniques are often applied within wireless networks to reduce security threats. As a benefit, the decentralized nature of network control in MANETs provides additional robustness against the single points of failure of more centralized approaches.
4) 有限的物理安全性：移动无线网络通常比固定电缆网络更容易受到物理安全威胁。应仔细考虑窃听、欺骗和拒绝服务攻击的可能性增加。现有的链路安全技术通常应用于无线网络中以减少安全威胁。作为一个好处，移动自组网中网络控制的分散性提供了额外的鲁棒性，以抵抗更集中的方法的单点故障。
In addition, some envisioned networks (e.g. mobile military networks or highway networks) may be relatively large (e.g. tens or hundreds of nodes per routing area). The need for scalability is not unique to MANETS. However, in light of the preceding characteristics, the mechanisms required to achieve scalability likely are.
此外，一些设想的网络（例如，移动军事网络或公路网络）可能相对较大（例如，每个路由区域有数十个或数百个节点）。对可伸缩性的需求并非MANET所独有。然而，鉴于上述特征，实现可伸缩性所需的机制可能是。
These characteristics create a set of underlying assumptions and performance concerns for protocol design which extend beyond those guiding the design of routing within the higher-speed, semi-static topology of the fixed Internet.
这些特性为协议设计创建了一组基本假设和性能问题，这些假设和性能问题超出了在固定互联网的高速半静态拓扑中指导路由设计的假设和性能问题。
The intent of the newly formed IETF manet working group is to develop a peer-to-peer mobile routing capability in a purely mobile, wireless domain. This capability will exist beyond the fixed network (as supported by traditional IP networking) and beyond the one-hop fringe of the fixed network.
新成立的IETF manet工作组的目的是在纯移动无线领域开发对等移动路由能力。这种能力将超越固定网络（由传统IP网络支持）和固定网络的单跳边缘。
The near-term goal of the manet working group is to standardize one (or more) intra-domain unicast routing protocol(s), and related network-layer support technology which:
manet工作组的近期目标是标准化一个（或多个）域内单播路由协议和相关的网络层支持技术，其：
* provides for effective operation over a wide range of mobile networking "contexts" (a context is a set of characteristics describing a mobile network and its environment);
* 提供在广泛的移动网络“上下文”（上下文是描述移动网络及其环境的一组特征）上的有效操作；
* supports traditional, connectionless IP service;
* 支持传统的无连接IP服务；
* reacts efficiently to topological changes and traffic demands while maintaining effective routing in a mobile networking context.
* 对拓扑变化和流量需求作出有效反应，同时在移动网络环境中保持有效路由。
The working group will also consider issues pertaining to addressing, security, and interaction/interfacing with lower and upper layer protocols. In the longer term, the group may look at the issues of layering more advanced mobility services on top of the initial unicast routing developed. These longer term issues will likely include investigating multicast and QoS extensions for a dynamic, mobile area.
工作组还将考虑与下层协议和上层协议相关的寻址、安全和交互/接口问题。从长远来看，该小组可能会考虑在开发的初始单播路由之上分层更高级的移动服务的问题。这些长期问题可能包括研究动态移动区域的多播和QoS扩展。
An improved mobile routing capability at the IP layer can provide a benefit similar to the intention of the original Internet, viz. "an interoperable internetworking capability over a heterogeneous networking infrastructure". In this case, the infrastructure is wireless, rather than hardwired, consisting of multiple wireless technologies, channel access protocols, etc. Improved IP routing and related networking services provide the glue to preserve the integrity of the mobile internetwork segment in this more dynamic environment.
IP层改进的移动路由能力可以提供类似于原始互联网意图的好处，即。“异构网络基础设施上的互操作互联能力”。在这种情况下，基础设施是无线的，而不是硬连线的，由多种无线技术、信道接入协议等组成。改进的IP路由和相关网络服务提供了粘合剂，可以在这种更加动态的环境中保持移动互联网部分的完整性。
In other words, a real benefit to using IP-level routing in a MANET is to provide network-level consistency for multihop networks composed of nodes using a *mixture* of physical-layer media; i.e. a mixture of what are commonly thought of as subnet technologies. A MANET node principally consists of a router, which may be physically attached to multiple IP hosts (or IP-addressable devices), which has potentially *multiple* wireless interfaces--each interface using a *different* wireless technology. Thus, a MANET node with interfaces using technologies A and B can communicate with any other MANET node possessing an interface with technology A or B. The multihop connectivity of technology A forms a physical-layer multihop topology, the multihop connectivity of technology B forms *another* physical-layer topology (which may differ from that of A's topology), and the *union* of these topologies forms another topology (in graph theoretic terms--a multigraph), termed the "IP routing fabric", of the MANET. MANET nodes making routing decisions using the IP fabric can intercommunicate using either or both physical-layer topologies simultaneously. As new physical-layer technologies are developed, new device drivers can be written and another physical-layer multihop topology can be seamlessly added to the IP fabric. Likewise, older technologies can easily be dropped. Such is the functionality and architectural flexibility that IP-layer routing can support, which brings with it hardware economies of scale.
换句话说，在MANET中使用IP级路由的真正好处是为使用*混合*物理层媒体的节点组成的多跳网络提供网络级一致性；i、 e.通常被认为是子网技术的混合。MANET节点主要由路由器组成，路由器可以物理连接到多个IP主机（或IP可寻址设备），其具有潜在的多个无线接口——每个接口使用不同的无线技术。因此，具有使用技术a和B的接口的MANET节点可以与具有与技术a或B的接口的任何其他MANET节点通信。技术a的多跳连接形成物理层多跳拓扑，技术B的多跳连接形成*另一*物理层拓扑（这可能不同于A的拓扑），这些拓扑的“并集”形成了另一个拓扑（用图论术语——多重图），称为“IP路由结构”，的MANET。使用IP结构进行路由决策的MANET节点可以同时使用其中一种或两种物理层拓扑进行通信。随着新的物理层技术的发展，可以编写新的设备驱动程序，并且可以将另一种物理层多跳拓扑无缝添加到IP结构。同样，旧的技术这就是IP层路由可以支持的功能和架构灵活性，这带来了硬件规模经济。
The concept of a "node identifier" (separate and apart from the concept of an "interface identifier") is crucial to supporting the multigraph topology of the routing fabric. It is what *unifies* a set of wireless interfaces and identifies them as belonging to the same
“节点标识符”的概念（与“接口标识符”的概念分开）对于支持路由结构的多图拓扑至关重要。它是*统一*一组无线接口并将它们标识为属于同一个接口的东西
mobile platform. This approach permits maximum flexibility in address assignment. Node identifiers are used at the IP layer for routing computations.
移动平台。这种方法允许地址分配具有最大的灵活性。节点标识符在IP层用于路由计算。
In the near term, it is currently envisioned that MANETs will function as *stub* networks, meaning that all traffic carried by MANET nodes will either be sourced or sinked within the MANET. Because of bandwidth and possibly power constraints, MANETs are not presently envisioned to function as *transit* networks carrying traffic which enters and then leaves the MANET (although this restriction may be removed by subsequent technology advances). This substantially reduces the amount of route advertisement required for interoperation with the existing fixed Internet. For stub operation, routing interoperability in the near term may be achieved using some combination of mechanisms such as MANET-based anycast and mobile IP. Future interoperability may be achieved using mechanisms other than mobile IP.
在短期内，目前设想MANET将作为*存根*网络运行，这意味着MANET节点承载的所有流量将在MANET内来源或下沉。由于带宽和可能的功率限制，MANET目前不被设想为承载进入和离开MANET的流量的*传输*网络（尽管这种限制可以通过后续的技术进步来消除）。这大大减少了与现有固定互联网互操作所需的路由广告量。对于存根操作，短期内的路由互操作性可以使用一些机制的组合来实现，例如基于MANET的选播和移动IP。未来的互操作性可以使用移动IP以外的机制来实现。
Interaction with Standard IP Routing will be greatly facilitated by usage of a common MANET addressing approach by all MANET routing protocols. Development of such an approach is underway which permits routing through a multi-technology fabric, permits multiple hosts per router and ensures long-term interoperability through adherence to the IP addressing architecture. Supporting these features appears only to require identifying host and router interfaces with IP addresses, identifying a router with a separate Router ID, and permitting routers to have multiple wired and wireless interfaces.
通过所有MANET路由协议使用公共MANET寻址方法，将极大地促进与标准IP路由的交互。这种方法的开发正在进行中，它允许通过多技术结构进行路由，允许每个路由器有多个主机，并通过遵守IP寻址体系结构确保长期互操作性。支持这些功能似乎只需要使用IP地址标识主机和路由器接口，使用单独的路由器ID标识路由器，并允许路由器具有多个有线和无线接口。
To judge the merit of a routing protocol, one needs metrics--both qualitative and quantitative--with which to measure its suitability and performance. These metrics should be *independent* of any given routing protocol.
为了判断路由协议的优点，我们需要衡量其适用性和性能的指标——定性和定量指标。这些指标应与任何给定的路由协议“独立”。
The following is a list of desirable qualitative properties of MANET routing protocols:
以下是MANET路由协议的理想定性属性列表：
1) Distributed operation: This is an essential property, but it should be stated nonetheless.
1) 分布式操作：这是一个基本属性，但仍应加以说明。
2) Loop-freedom: Not required per se in light of certain quantitative measures (i.e. performance criteria), but generally desirable to avoid problems such as worst-case phenomena, e.g. a small fraction of packets spinning around in the network for arbitrary time periods. Ad hoc solutions such as TTL values can
2) 环路自由度：根据某些定量度量（即性能标准），本身不需要，但通常需要避免最坏情况现象等问题，例如，一小部分数据包在网络中旋转任意时间段。临时解决方案（如TTL值）可以
bound the problem, but a more structured and well-formed approach is generally desirable as it usually leads to better overall performance.
虽然解决了这个问题，但通常需要一种更结构化、形式更完善的方法，因为它通常会带来更好的总体性能。
3) Demand-based operation: Instead of assuming an uniform traffic distribution within the network (and maintaining routing between all nodes at all times), let the routing algorithm adapt to the traffic pattern on a demand or need basis. If this is done intelligently, it can utilize network energy and bandwidth resources more efficiently, at the cost of increased route discovery delay.
3) 基于需求的操作：让路由算法根据需求或需要适应流量模式，而不是假设网络内的流量分布均匀（并始终保持所有节点之间的路由）。如果这是智能化的，它可以更有效地利用网络能量和带宽资源，但代价是增加路由发现延迟。
4) Proactive operation: The flip-side of demand-based operation. In certain contexts, the additional latency demand-based operation incurs may be unacceptable. If bandwidth and energy resources permit, proactive operation is desirable in these contexts.
4) 主动操作：基于需求的操作的另一面。在某些情况下，可能无法接受基于需求的额外延迟操作。如果带宽和能源资源允许，在这些情况下，主动操作是可取的。
5) Security: Without some form of network-level or link-layer security, a MANET routing protocol is vulnerable to many forms of attack. It may be relatively simple to snoop network traffic, replay transmissions, manipulate packet headers, and redirect routing messages, within a wireless network without appropriate security provisions. While these concerns exist within wired infrastructures and routing protocols as well, maintaining the "physical" security of of the transmission media is harder in practice with MANETs. Sufficient security protection to prohibit disruption of modification of protocol operation is desired. This may be somewhat orthogonal to any particular routing protocol approach, e.g. through the application of IP Security techniques.
5) 安全性：如果没有某种形式的网络级或链路层安全性，MANET路由协议容易受到多种形式的攻击。在无线网络中，在没有适当安全规定的情况下，窥探网络流量、重播传输、操纵分组报头和重定向路由消息可能相对简单。虽然这些问题也存在于有线基础设施和路由协议中，但在MANET的实践中，维护传输介质的“物理”安全更为困难。需要足够的安全保护，以防止协议操作修改中断。这可能在某种程度上与任何特定路由协议方法正交，例如通过应用IP安全技术。
6) "Sleep" period operation: As a result of energy conservation, or some other need to be inactive, nodes of a MANET may stop transmitting and/or receiving (even receiving requires power) for arbitrary time periods. A routing protocol should be able to accommodate such sleep periods without overly adverse consequences. This property may require close coupling with the link-layer protocol through a standardized interface.
6) “睡眠”期操作：由于节能或其他一些需要处于非活动状态，MANET的节点可能会在任意时间段内停止发送和/或接收（甚至接收需要电源）。路由协议应该能够适应这样的睡眠时间，而不会产生过度不利的后果。此属性可能需要通过标准化接口与链路层协议紧密耦合。
7) Unidirectional link support: Bidirectional links are typically assumed in the design of routing algorithms, and many algorithms are incapable of functioning properly over unidirectional links. Nevertheless, unidirectional links can and do occur in wireless networks. Oftentimes, a sufficient number of duplex links exist so that usage of unidirectional links is of limited added value. However, in situations where a pair of unidirectional links (in opposite directions) form the only bidirectional connection between two ad hoc regions, the ability to make use of them is valuable.
7) 单向链路支持：在路由算法的设计中通常假设双向链路，并且许多算法无法在单向链路上正常工作。然而，单向链路可以也确实发生在无线网络中。通常，存在足够数量的双工链路，因此单向链路的使用具有有限的附加值。然而，在一对单向链路（在相反方向）形成两个自组织区域之间的唯一双向连接的情况下，利用它们的能力是有价值的。
The following is a list of quantitative metrics that can be used to assess the performance of any routing protocol.
以下是可用于评估任何路由协议性能的量化指标列表。
1) End-to-end data throughput and delay: Statistical measures of data routing performance (e.g., means, variances, distributions) are important. These are the measures of a routing policy's effectiveness--how well it does its job--as measured from the *external* perspective of other policies that make use of routing.
1) 端到端数据吞吐量和延迟：数据路由性能的统计度量（例如，均值、方差、分布）很重要。这些是路由策略有效性的衡量标准——它的工作表现如何——从使用路由的其他策略的“外部”角度进行衡量。
2) Route Acquisition Time: A particular form of *external* end-to-end delay measurement--of particular concern with "on demand" routing algorithms--is the time required to establish route(s) when requested.
2) 路由获取时间：一种特殊形式的*外部*端到端延迟测量——特别关注“按需”路由算法——是在请求时建立路由所需的时间。
3) Percentage Out-of-Order Delivery: An external measure of connectionless routing performance of particular interest to transport layer protocols such as TCP which prefer in-order delivery.
3) 无序交付百分比：对无连接路由性能的一种外部度量，对传输层协议（如TCP）特别感兴趣，后者更喜欢有序交付。
4) Efficiency: If data routing effectiveness is the external measure of a policy's performance, efficiency is the *internal* measure of its effectiveness. To achieve a given level of data routing performance, two different policies can expend differing amounts of overhead, depending on their internal efficiency. Protocol efficiency may or may not directly affect data routing performance. If control and data traffic must share the same channel, and the channel's capacity is limited, then excessive control traffic often impacts data routing performance.
4) 效率：如果数据路由有效性是策略性能的外部度量，则效率是其有效性的*内部*度量。为了实现给定级别的数据路由性能，两种不同的策略可能会消耗不同的开销，这取决于它们的内部效率。协议效率可能直接影响数据路由性能，也可能不直接影响数据路由性能。如果控制流量和数据流量必须共享同一个信道，并且信道容量有限，那么过多的控制流量通常会影响数据路由性能。
It is useful to track several ratios that illuminate the *internal* efficiency of a protocol in doing its job (there may be others that the authors have not considered):
跟踪说明协议在执行其工作时的*内部*效率的几个比率是有用的（可能还有作者没有考虑的其他比率）：
* Average number of data bits transmitted/data bit delivered-- this can be thought of as a measure of the bit efficiency of delivering data within the network. Indirectly, it also gives the average hop count taken by data packets.
* 传输的数据位/传输的数据位的平均数——这可以被认为是网络内传输数据的位效率的度量。间接地，它也给出了数据包的平均跳数。
* Average number of control bits transmitted/data bit delivered--this measures the bit efficiency of the protocol in expending control overhead to delivery data. Note that this should include not only the bits in the routing control packets, but also the bits in the header of the data packets. In other words, anything that is not data is control overhead, and should be counted in the control portion of the algorithm.
* 传输的控制位/传输的数据位的平均数量——这衡量协议在将控制开销扩展到传输数据方面的位效率。注意，这不仅应该包括路由控制分组中的比特，还应该包括数据分组的报头中的比特。换句话说，任何不是数据的东西都是控制开销，应该计入算法的控制部分。
* Average number of control and data packets transmitted/data packet delivered--rather than measuring pure algorithmic efficiency in terms of bit count, this measure tries to capture a protocol's channel access efficiency, as the cost of channel access is high in contention-based link layers.
* 传输的控制和数据包/交付的数据包的平均数量——由于基于争用的链路层中的信道访问成本很高，因此，该度量方法试图捕获协议的信道访问效率，而不是根据位计数来测量纯算法效率。
Also, we must consider the networking *context* in which a protocol's performance is measured. Essential parameters that should be varied include:
此外，我们必须考虑网络*上下文*，其中协议的性能被测量。应改变的基本参数包括：
1) Network size--measured in the number of nodes
1) 网络大小——以节点数衡量
2) Network connectivity--the average degree of a node (i.e. the average number of neighbors of a node)
2) 网络连通性——节点的平均程度（即节点的平均邻居数）
3) Topological rate of change--the speed with which a network's topology is changing
3) 拓扑变化率——网络拓扑变化的速度
4) Link capacity--effective link speed measured in bits/second, after accounting for losses due to multiple access, coding, framing, etc.
4) 链路容量——在考虑多址、编码、帧等造成的损失后，以比特/秒为单位测量的有效链路速度。
5) Fraction of unidirectional links--how effectively does a protocol perform as a function of the presence of unidirectional links?
5) 单向链路的分数——作为单向链路存在的函数，协议的性能如何？
6) Traffic patterns--how effective is a protocol in adapting to non-uniform or bursty traffic patterns?
6) 流量模式——协议在适应非均匀或突发流量模式方面有多有效？
7) Mobility--when, and under what circumstances, is temporal and spatial topological correlation relevant to the performance of a routing protocol? In these cases, what is the most appropriate model for simulating node mobility in a MANET?
7) 移动性——时间和空间拓扑相关性在什么情况下与路由协议的性能相关？在这些情况下，在MANET中模拟节点移动性最合适的模型是什么？
8) Fraction and frequency of sleeping nodes--how does a protocol perform in the presence of sleeping and awakening nodes?
8) 休眠节点的比例和频率——协议在休眠和唤醒节点存在时如何执行？
A MANET protocol should function effectively over a wide range of networking contexts--from small, collaborative, ad hoc groups to larger mobile, multihop networks. The preceding discussion of characteristics and evaluation metrics somewhat differentiate MANETs from traditional, hardwired, multihop networks. The wireless networking environment is one of scarcity rather than abundance, wherein bandwidth is relatively limited, and energy may be as well.
MANET协议应该在广泛的网络环境中有效运行——从小型的、协作的、临时的组到大型的移动的、多跳的网络。前面对特征和评估指标的讨论在某种程度上区分了MANET与传统的硬连线多跳网络。无线网络环境是一个稀缺而非充裕的环境，其中带宽相对有限，能量也可能有限。
In summary, the networking opportunities for MANETs are intriguing and the engineering tradeoffs are many and challenging. A diverse set of performance issues requires new protocols for network control.
总而言之，移动自组网的网络机遇是诱人的，工程上的权衡是众多且具有挑战性的。一系列不同的性能问题需要新的网络控制协议。
A question which arises is "how should the *goodness* of a policy be measured?". To help answer that, we proposed here an outline of protocol evaluation issues that highlight performance metrics that can help promote meaningful comparisons and assessments of protocol performance. It should be recognized that a routing protocol tends to be well-suited for particular network contexts, and less well-suited for others. In putting forth a description of a protocol, both its *advantages* and *limitations* should be mentioned so that the appropriate networking context(s) for its usage can be identified. These attributes of a protocol can typically be expressed *qualitatively*, e.g., whether the protocol can or cannot support shortest-path routing. Qualitative descriptions of this nature permit broad classification of protocols, and form a basis for more detailed *quantitative* assessments of protocol performance. In future documents, the group may put forth candidate recommendations regarding protocol design for MANETs. The metrics and the philosophy presented within this document are expected to continue to evolve as MANET technology and related efforts mature.
由此产生的一个问题是“如何衡量政策的“优点”。为了帮助回答这个问题，我们在这里提出了一个协议评估问题的概要，突出了可以帮助促进协议性能的有意义比较和评估的性能指标。应该认识到，路由协议往往非常适合特定的网络环境，而不太适合其他网络环境。在提出协议的描述时，应提及其*优点*和*限制*，以便能够识别其使用的适当网络上下文。协议的这些属性通常可以*定性地*表示，例如，协议是否能够支持最短路径路由。这种性质的定性描述允许对协议进行广泛的分类，并形成协议性能更详细*定量*评估的基础。在未来的文件中，该小组可能会提出关于移动自组网协议设计的候选建议。随着MANET技术和相关工作的成熟，本文件中提出的指标和理念有望继续发展。
Mobile wireless networks are generally more prone to physical security threats than are fixed, hardwired networks. Existing link-level security techniques (e.g. encryption) are often applied within wireless networks to reduce these threats. Absent link-level encryption, at the network layer, the most pressing issue is one of inter-router authentication prior to the exchange of network control information. Several levels of authentication ranging from no security (always an option) and simple shared-key approaches, to full public key infrastructure-based authentication mechanisms will be explored by the group. As an adjunct to the working groups efforts, several optional authentication modes may be standardized for use in MANETs.
移动无线网络通常比固定的硬连线网络更容易受到物理安全威胁。现有的链路级安全技术（如加密）通常应用于无线网络中，以减少这些威胁。如果没有链路级加密，在网络层，最紧迫的问题是在交换网络控制信息之前进行路由器间身份验证。该小组将探讨从无安全性（始终是一个选项）和简单共享密钥方法到基于完整公钥基础设施的认证机制的多个级别的认证。作为工作组工作的一个补充，可以标准化几种可选的认证模式以用于MANET。
[1] Adamson, B., "Tactical Radio Frequency Communication Requirements for IPng", RFC 1677, August 1994.
[1] Adamson，B.，“IPng的战术射频通信要求”，RFC 16771994年8月。
Authors' Addresses
作者地址
M. Scott Corson Institute for Systems Research University of Maryland College Park, MD 20742
史葛Colson系统研究学院马里兰大学学院公园，MD 20742
Phone: (301) 405-6630 EMail: corson@isr.umd.edu
电话：（301）405-6630电子邮件：corson@isr.umd.edu
Joseph Macker Information Technology Division Naval Research Laboratory Washington, DC 20375
Joseph Macker信息技术部海军研究实验室华盛顿特区20375
Phone: (202) 767-2001 EMail: macker@itd.nrl.navy.mil
电话：（202）767-2001电子邮件：macker@itd.nrl.navy.mil
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