Network Working Group J. Kempf
Request for Comments: 3132 Sun Microsystems
Category: Informational June 2001
Network Working Group J. Kempf
Request for Comments: 3132 Sun Microsystems
Category: Informational June 2001
Dormant Mode Host Alerting ("IP Paging") Problem Statement
休眠模式主机警报（“IP分页”）问题声明
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 (2001). All Rights Reserved.
版权所有（C）互联网协会（2001年）。版权所有。
Abstract
摘要
This memo describes paging, assesses the need for IP paging, and presents a list of recommendations for Seamoby charter items regarding work on paging. The results are specifically directed toward the task undertaken by the design team, and are not meant to be the definitive word on paging for all time, nor to be binding on Seamoby or other working groups, should the situation with regard to IP mobility protocols or radio link support undergo a major change.
本备忘录描述了寻呼，评估了IP寻呼的必要性，并提供了Seamoby租船公司关于寻呼工作的建议列表。这些结果专门针对设计团队承担的任务，如果IP移动协议或无线链路支持的情况发生重大变化，则这些结果并不意味着永远是寻呼的决定性词汇，也不意味着对Seamoby或其他工作组具有约束力。
The IESG has requested that the Seamoby Working Group develop a problem statement about the need for additional protocol work to support alerting of dormant mode mobile hosts, commonly known as IP paging, for seamless IP mobility. The paging design team interpreted this as direction to examine whether location of a mobile node in power saving mode can be supported by the existing Mobile IPv4 and Mobile IPv6 protocols given existing radio link protocols.
IESG已要求Seamoby工作组制定一份问题声明，说明需要额外的协议工作来支持休眠模式移动主机（通常称为IP寻呼）的警报，以实现无缝IP移动。寻呼设计团队将此理解为一个方向，即在现有无线链路协议的情况下，检查现有移动IPv4和移动IPv6协议是否支持节能模式下移动节点的位置。
Many existing radio link protocols and mobile systems support location of and radio link establishment with mobile nodes that are in power saving mode and hence are not actively listening for delivery of IP packets all the time or are not listening on the radio channels normally associated with delivering IP traffic to mobile nodes. This alerting functionality allows mobile nodes to reduce power consumption and decreases signaling load on the network for tracking mobiles that are not actively participating in IP packet generation or reception.
许多现有的无线链路协议和移动系统支持移动节点的定位和无线链路的建立，移动节点处于省电模式，因此没有一直积极地监听IP分组的传送，或者没有监听通常与向移动节点传送IP流量相关联的无线信道。此警报功能允许移动节点降低功耗并减少网络上的信令负载，以跟踪未积极参与IP数据包生成或接收的移动设备。
When a mobile is in low power consumption mode, special steps need to be taken to locate the mobile and alert it. These steps differ depending on the radio link, but the generic name for this process is paging, a term that is commonly used in cellular telephony.
当手机处于低功耗模式时，需要采取特殊步骤定位手机并向其发出警报。这些步骤因无线链路的不同而有所不同，但此过程的通用名称是寻呼，这是蜂窝电话中常用的一个术语。
In this document, after some initial definitions and material related to more clearly explaining what paging is, we assess the need for paging in existing IP mobility protocols (namely Mobile IP [1] [2]). We then develop a list of work items for the Seamoby working group related to this need. Note that the discussion in this document and the conclusions regarding work items are directed toward existing IP mobility protocols and existing radio link protocols. Should a major change occur in radio link support or the available IP mobility protocols, such as the introduction of a micromobility protocol for IP, the issues examined in this document may need to be revisited.
在本文档中，在一些与更清楚地解释分页是什么相关的初始定义和材料之后，我们评估了现有IP移动协议（即移动IP[1][2]）中分页的必要性。然后，我们为Seamoby工作组制定一份与此需求相关的工作项目清单。请注意，本文档中的讨论和有关工作项的结论是针对现有IP移动协议和现有无线链路协议的。如果无线链路支持或可用的IP移动性协议发生重大变化，例如为IP引入微移动性协议，则可能需要重新讨论本文档中检查的问题。
The following definitions are relevant with respect to clarifying the paging functionality:
以下定义与阐明分页功能相关：
Dormant Mode - A state in which the mobile restricts its ability to receive normal IP traffic by reducing monitoring of radio channels. This allows the mobile to save power and reduces signaling load on the network.
休眠模式-移动设备通过减少对无线信道的监控来限制其接收正常IP流量的能力的状态。这允许移动设备节省电力并减少网络上的信令负载。
Time-slotted Dormant Mode - A dormant mode implementation in which the mobile alternates between periods of not listening for any radio traffic and listening for traffic. Time-slotted dormant mode implementations are typically synchronized with the network so the network can deliver traffic to the mobile during listening periods. Additionally, the mobile may be restricted to listening on specific signaling channels that, according to current practice, are not typically used to carry IP traffic.
时隙休眠模式-一种休眠模式实现，移动设备在不监听任何无线电通信和监听通信之间交替进行。时隙休眠模式实现通常与网络同步，因此网络可以在侦听期间向移动设备传送流量。另外，移动设备可被限制在特定信令信道上监听，根据当前实践，该特定信令信道通常不用于承载IP业务。
Paging - As a consequence of a mobile-bound packet destined for a mobile currently in dormant mode, signaling by the network through radio access points directed to locating the mobile and alerting it to establish a last hop connection. This messaging is in addition to simply delivering the packet to the mobile, i.e., last hop routing of packets is NOT considered to be paging.
寻呼-作为发送给当前处于休眠模式的移动设备的移动绑定数据包的结果，网络通过无线接入点发送信号，以定位移动设备并提醒其建立最后一跳连接。此消息传递是除了简单地将数据包传送到移动设备之外的，即数据包的最后一跳路由不被认为是寻呼。
Paging Area - Collection of radio access points that are signaled to locate a dormant mode mobile node. A paging area does not necessarily correspond to an IP subnet. A dormant mode mobile node may be required to signal to the network when it crosses a paging area boundary, in order that the network can maintain a rough idea of where the mobile is located.
寻呼区域-无线接入点的集合，这些无线接入点被发信号以定位休眠模式移动节点。寻呼区域不一定对应于IP子网。休眠模式移动节点可能需要在其跨越寻呼区域边界时向网络发送信号，以便网络能够大致了解移动设备的位置。
Paging Channel - A radio channel dedicated to signaling dormant mode mobiles for paging purposes. By current practice, the protocol used on a paging channel is usually dictated by the radio link protocol, although some paging protocols have provision for carrying arbitrary traffic (and thus could potentially be used to carry IP).
寻呼信道-专用于向休眠模式手机发送寻呼信号的无线信道。根据目前的实践，寻呼信道上使用的协议通常由无线链路协议决定，尽管一些寻呼协议具有承载任意通信量的规定（因此可能用于承载IP）。
Traffic Channel - The radio channel on which IP traffic to an active mobile is typically sent. This channel is used by a mobile that is actively sending and receiving IP traffic, and is not continuously active in a dormant mode mobile. For some radio link protocols, this may be the only channel available.
通信信道-通常向活动移动设备发送IP通信的无线信道。此信道由主动发送和接收IP流量的移动设备使用，并且在休眠移动模式下不连续活动。对于某些无线链路协议，这可能是唯一可用的信道。
Paging Area Registrations - Signaling from a dormant mode mobile node to the network when the mobile node crosses a paging area boundary to establish the mobile node's presence in the new paging area.
寻呼区域注册-当移动节点跨越寻呼区域边界以建立移动节点在新寻呼区域中的存在时，从休眠模式移动节点向网络发送信号。
Dormant mode is advantageous to a mobile node and the network for the following reasons:
休眠模式有利于移动节点和网络，原因如下：
- Power savings. By reducing the amount of time the mobile is required to listen to the radio interface, the drain on the mobile node's battery is reduced.
- 省电。通过减少移动设备收听无线电接口所需的时间，移动节点电池的耗电量减少。
- Reduced signaling for location tracking. By requiring the mobile to only signal when it crosses a paging area boundary rather than when it switches between radio access points, the amount of signaling for tracking the mobile is reduced because paging areas typically contain many radio access points.
- 减少了位置跟踪的信令。通过要求移动设备仅在其跨越寻呼区域边界而不是在其在无线接入点之间切换时发出信号，用于跟踪移动设备的信令量减少，因为寻呼区域通常包含许多无线接入点。
In existing radio link protocols, there is a clear distinction between those protocols that support dormant mode only and those that support dormant mode with paging. Radio link protocols that do not support paging have no paging areas, no dedicated paging channel, and no radio link protocol specifically directed towards locating a dormant mode mobile, while radio link protocols that do support paging have these features. Although generalizations always run the risk of being contradicted by specific exceptions, the following comparison of existing radio link protocol support for these two cases may be instructive.
在现有的无线链路协议中，那些只支持休眠模式的协议和那些支持带寻呼的休眠模式的协议之间存在着明显的区别。不支持寻呼的无线链路协议没有寻呼区域，没有专用的寻呼信道，也没有专门针对定位休眠模式移动设备的无线链路协议，而支持寻呼的无线链路协议具有这些功能。尽管一般化总是有被特定的例外情况所抵触的风险，下面对这两种情况下现有的无线链路协议支持进行比较可能是有指导意义的。
In radio link protocols that only support dormant mode, a dormant mode mobile node typically operates in time slotted mode and there is only one radio channel available, namely the traffic channel. The mobile node periodically wakes up, and, synchronously, the radio access point in the network with which the mobile node is associated delivers any IP packets that have arrived while the mobile node was asleep. Radio access points are required to buffer incoming packets for dormant mode mobiles; exactly how many packets and how long they are buffered are implementation dependent.
在仅支持休眠模式的无线链路协议中，休眠模式移动节点通常在时隙模式下工作，并且只有一个可用的无线信道，即业务信道。移动节点周期性地唤醒，并且，与移动节点相关联的网络中的无线电接入点同步地递送在移动节点睡眠时到达的任何IP分组。无线接入点需要为休眠模式移动设备缓冲传入的数据包；确切的数据包数量和缓冲时间取决于实现。
If the mobile node happens to move out of range of the access point with which it was associated, while it is in dormant mode, it discovers this when it awakens and reassociates with a new access point. The new access point then contacts the old access point over the wired backbone, the old access point sends any buffered packets, and the new access point delivers them to the mobile.
如果移动节点在处于休眠模式时恰好移动到与之关联的接入点的范围之外，则当其唤醒并与新接入点重新关联时，它会发现这一点。然后，新接入点通过有线主干网与旧接入点联系，旧接入点发送任何缓冲数据包，新接入点将它们发送给移动设备。
Radio link protocols with dormant mode support only are typically wireless LAN protocols in unlicensed spectrum in which the mobile node is not charged for using a traffic channel, and hence there is no need for conserving spectrum usage.
仅支持休眠模式的无线链路协议通常是未经许可频谱中的无线LAN协议，其中移动节点使用业务信道不收费，因此不需要节约频谱使用。
In radio link protocols with support for paging, the radio link typically supports more than one channel. A dormant mode mobile node may operate in time slotted mode, periodically waking up to listen to the paging channel, or it may simply listen to the paging channel continuously. The important point is that the mobile does not listen to nor transmit on a traffic channel while in dormant mode.
在支持寻呼的无线链路协议中，无线链路通常支持多个信道。休眠模式移动节点可以在时隙模式下操作，周期性地唤醒以侦听寻呼信道，或者它可以仅仅连续侦听寻呼信道。重要的一点是，当处于休眠模式时，移动设备不会在通信信道上侦听或传输。
The radio access points are grouped into paging areas, and the radio link protocol supports periodic signaling between the mobile and the network only when the mobile crosses a paging area boundary, for the purpose of giving the network a rough idea of the mobile's location (paging area registrations). Some deployments of paging do not even use paging area registrations. They use heuristics to determine where the mobile is located when a packet arrives, in which case, no signaling is required while the mobile is in dormant mode.
无线电接入点被分组为寻呼区域，并且无线电链路协议仅当移动设备跨越寻呼区域边界时才支持移动设备和网络之间的周期性信令，以便使网络大致了解移动设备的位置（寻呼区域注册）。某些分页部署甚至不使用分页区域注册。他们使用启发式来确定当数据包到达时移动设备的位置，在这种情况下，当移动设备处于休眠模式时，不需要信令。
An incoming packet is directed to the paging area where the mobile last reported, or the paging area is determined by heuristics. The network performs a radio link page by sending out a signal on the paging channel. The signal may be repeated until the mobile answers or a timeout occurs. In the former case, the packet is delivered, in the latter, the mobile is assumed to be unreachable.
传入数据包被定向到移动设备上次报告的寻呼区域，或者寻呼区域由启发式算法确定。网络通过在寻呼信道上发送信号来执行无线链路寻呼。该信号可能会重复，直到手机应答或出现超时。在前一种情况下，发送分组，在后一种情况下，假设移动设备不可到达。
Radio link protocols with paging support tend to be in licensed spectrum where the network operator has an interest in reducing the amount of signaling over traffic channels. Such reduction frees traffic channel spectrum for revenue-producing use, and avoids charging the customer for signaling overhead.
具有寻呼支持的无线链路协议倾向于使用许可频谱，网络运营商希望减少业务信道上的信令量。这样的减少释放了用于创收用途的业务信道频谱，并避免了向客户收取信令开销。
In this section, we consider whether IP paging support is necessary. We first consider radio link protocols that have no support for paging. We then examine radio link protocols that have paging support. As discussed in the introduction, the focus is on whether the existing IETF mobility protocol, namely Mobile IP, requires enhancement. We also briefly discuss the relationship between paging and a potential future micromobility protocol.
在本节中，我们考虑IP寻呼支持是否是必要的。我们首先考虑不支持分页的无线链路协议。然后，我们研究具有分页支持的无线链路协议。正如导言中所讨论的，重点在于现有IETF移动性协议（即移动IP）是否需要增强。我们还简要讨论了分页和未来可能的微移动协议之间的关系。
One possible justification for IP paging is for radio links that do not support paging. The reasoning is that an IP paging protocol could allow location of a dormant mode mobile in radio networks that do not support paging in the radio protocol.
IP寻呼的一个可能理由是不支持寻呼的无线链路。原因是IP寻呼协议可以允许在无线网络中定位休眠模式移动设备，而无线网络不支持无线协议中的寻呼。
An important point to keep in mind when considering this possibility is that, for radio links that do support paging, paging is typically used to locate mobiles for which the network has a rough idea of where the mobile is located. More specifically, in order to conserve signaling between the network and the mobile and to reduce power drain on the mobile, the mobile only updates the network about its location when it crosses a paging area boundary (if even then), which is far less frequent than when it crosses a radio access point boundary. If IP paging is to be of any use to radio link protocols that do not support paging, it must also be the case that it allows the network to maintain a rough idea of where the mobile is, otherwise, the amount of signaling involved in tracking the mobile and power drain on the mobile is not reduced.
在考虑这种可能性时，需要记住的一点是，对于支持寻呼的无线链路，寻呼通常用于定位网络大致知道移动设备所在位置的移动设备。更具体地说，为了保存网络和移动设备之间的信令并减少移动设备上的功率消耗，移动设备仅在其跨越寻呼区域边界（即使如此）时更新网络关于其位置的信息，其频率远远低于其跨越无线接入点边界时的频率。如果IP寻呼对不支持寻呼的无线链路协议有任何用途，那么它还必须允许网络大致了解移动设备的位置，否则，跟踪移动设备所涉及的信令量和移动设备上的功率消耗不会减少。
However, as the description in the previous section indicates, for radio links without paging support, the network always has an *exact* idea of where the mobile is located. When the mobile moves into range of a new radio access point, it re-registers with the access point in that cell allowing the new access point to contact the old and deliver any buffered traffic. Additionally, the new access point at that time may choose to deliver a foreign agent advertisement (for Mobile IPv4) or router advertisement (for Mobile IPv6) to the mobile if the mobile node has changed subnets, so that the mobile can perform Mobile IP re-registration in order to make sure its IP routing is current. There is absolutely no ambiguity in the mobile's
然而，如前一节中的描述所示，对于不支持寻呼的无线链路，网络总是对移动设备的位置有一个“精确”的概念。当移动设备移动到新无线接入点的范围内时，它会在该小区中的接入点重新注册，从而允许新接入点与旧接入点联系并提供任何缓冲流量。此外，如果移动节点改变了子网，则此时的新接入点可以选择向移动设备发送外部代理广告（用于移动IPv4）或路由器广告（用于移动IPv6），以便移动设备可以执行移动IP重新注册以确保其IP路由是最新的。手机的功能绝对没有歧义
location as far as the network is concerned, and so the network can continue to route packets to the mobile node while the mobile is in dormant mode with assurance (modulo buffer overflows and timeouts at the radio access point) that the packets will be delivered to the mobile the next time it wakes up from dormant mode.
就网络而言的位置，因此当移动设备处于休眠模式时，网络可以继续将数据包路由到移动节点，并保证（无线接入点处的模缓冲区溢出和超时）数据包将在移动设备下次从休眠模式唤醒时交付给移动设备。
As a consequence, IP paging provides no advantages for radio link protocols in which the radio link does not have support for paging.
因此，IP寻呼对于无线链路不支持寻呼的无线链路协议没有任何优势。
In radio links that do support paging, there are two cases to consider: networks of radio links having a homogeneous radio technology and networks of radio links having heterogeneous radio technologies. We examine whether Mobile IP can support dormant mode location for both these cases.
在支持寻呼的无线链路中，有两种情况需要考虑：具有同质无线技术的无线链路网络和具有异质无线技术的无线链路网络。我们检查移动IP是否能够支持这两种情况下的休眠模式定位。
For homogeneous technology networks, the primary issue is whether signaling involved in Mobile IP is enough to provide support for locating dormant mode mobile nodes. Subnets constitute the unit of signaling for presence in IP. When a mobile node moves from one subnet to another, Mobile IP signaling is required to change the mobile's care-of address. This signaling establishes the mobile's presence in the new subnet. Paging areas constitute the unit of signaling for dormant mode mobile presence at the radio level. Paging area registrations or heuristics are used to establish a dormant mode mobile's presence in a particular paging area.
对于同构技术网络，主要问题是移动IP中涉及的信令是否足以为定位休眠模式移动节点提供支持。子网构成IP中存在的信令单元。当移动节点从一个子网移动到另一个子网时，需要移动IP信令来更改移动设备的转交地址。该信令建立移动设备在新子网中的存在。寻呼区域构成了无线电层休眠模式移动存在的信令单元。寻呼区域注册或试探法用于在特定寻呼区域建立休眠模式移动设备的存在。
If paging area registrations can always serve to trigger Mobile IP registrations, there is no need for an IP paging protocol because the network (specifically the home or hierarchical agent) will always have an up-to-date picture of where the mobile is and can always route packets to the mobile. The key determining factor with regard to whether paging area registrations can be used in this fashion is how subnets are mapped into paging areas. If it is always possible to map the two such that a paging area registration can serve as a transport for a Mobile IP registration, or some other technique (such as network assisted handoff [3] [4]) can be used to transfer the Mobile IP registration, then no IP paging protocol is needed.
如果寻呼区域注册始终可以触发移动IP注册，则不需要IP寻呼协议，因为网络（特别是家庭或分层代理）将始终具有移动设备所在位置的最新图片，并且始终可以将数据包路由到移动设备。关于是否可以以这种方式使用分页区域注册的关键决定因素是如何将子网映射到分页区域。如果始终可以映射这两者，使得寻呼区域注册可以用作移动IP注册的传输，或者可以使用某些其他技术（例如网络辅助切换[3][4]）来传输移动IP注册，则不需要IP寻呼协议。
In general, the mapping between paging areas and subnets can be arbitrary, but we consider initially a smooth subset relationship, in which paging areas are subsets of subnets or vice versa. Network topologies in which one subnet is split between two or more paging areas are therefore eliminated. The restriction is arbitrary, but by
通常，寻呼区域和子网之间的映射可以是任意的，但是我们最初考虑平滑子集关系，其中寻呼区域是子网的子集，反之亦然。因此，消除了一个子网在两个或多个寻呼区域之间分割的网络拓扑。这一限制是任意的，但有其局限性
starting here, we can discover whether additional work is needed. We also consider a case where paging area registrations in the radio layer protocol are always done. This is also optimistic.
从这里开始，我们可以发现是否需要额外的工作。我们还考虑了在无线层协议中寻呼区域注册的情况。这也是乐观的。
There are three cases:
有三种情况：
1) The topological boundaries of the paging area and subnet are identical.
1) 分页区域和子网的拓扑边界相同。
2) Multiple paging areas are part of the same subnet.
2) 多个分页区域是同一子网的一部分。
3) Multiple subnets are part of the same paging area.
3) 多个子网是同一寻呼区域的一部分。
Each case is considered in the following subsections.
以下小节将考虑每种情况。
In the case where radio paging areas map one to one onto IP subnets (and hence Mobile IPv4 foreign agents or IPv6 access routers), it is possible to use radio link paging together with Mobile IP handoff techniques for the network to track the mobile's location. If the paging area update protocol supports sending arbitrary packet data over the paging channel, the access router or foreign agent can send a router advertisement or foreign agent advertisement to the mobile as part of the signal that the mobile has entered the new paging area, and the mobile can send a Mobile IP registration as part of the paging area update. For other cases, enhancements to Mobile IP network-assisted handoff techniques can allow the network to track the mobile as it moves from paging area (== subnet) to paging area. Other uses of the Mobile IP registration protocol are also possible depending on the level of paging support for packet data. As a consequence, the home or hierarchical agent has complete knowledge of routes to the mobile and can route packets to the foreign agent or access router. Radio layer paging may be needed at the foreign agent or access router in order to re-establish a traffic channel with the mobile, but no IP paging is required.
在无线寻呼区域一对一映射到IP子网（因此移动IPv4外部代理或IPv6访问路由器）的情况下，可以将无线链路寻呼与网络的移动IP切换技术一起用于跟踪移动设备的位置。如果寻呼区域更新协议支持通过寻呼信道发送任意分组数据，则接入路由器或外部代理可以向移动设备发送路由器广告或外部代理广告，作为移动设备已进入新寻呼区域的信号的一部分，移动设备可以发送移动IP注册，作为寻呼区域更新的一部分。对于其他情况，对移动IP网络辅助切换技术的增强可以允许网络在移动设备从寻呼区域（=子网）移动到寻呼区域时跟踪移动设备。根据对分组数据的分页支持级别，移动IP注册协议的其他用途也是可能的。结果，归属或分层代理具有到移动设备的路由的完整知识，并且可以将分组路由到外部代理或接入路由器。外部代理或接入路由器可能需要无线层寻呼，以便与移动设备重新建立通信信道，但不需要IP寻呼。
The case where multiple radio paging areas map to a single IP subnet is the same as above, with the exception that the last hop Mobile IPv4 foreign agent or IPv6 access router for the subnet performs paging in multiple paging areas to locate the mobile.
多个无线寻呼区域映射到单个IP子网的情况与上述相同，但子网的最后一跳移动IPv4外部代理或IPv6访问路由器在多个寻呼区域执行寻呼以定位移动设备。
In the case where a single radio paging area maps onto multiple IP subnets, it is not possible to directly use Mobile IP handoff between last hop access routers or foreign agents to track the mobile's location as it moves, because the mobile does not signal its location when it changes subnets. Within the set of subnets that span the paging area, the mobile's movement is invisible to the L2 paging system, so a packet delivered to the mobile's last known location may result in a page that is answered in a different subnet.
在单个无线寻呼区域映射到多个IP子网的情况下，不可能在最后一跳接入路由器或外部代理之间直接使用移动IP切换来跟踪移动设备移动时的位置，因为移动设备在更改子网时不会发信号通知其位置。在跨越寻呼区域的一组子网中，二级寻呼系统看不到移动设备的移动，因此发送到移动设备最后一个已知位置的数据包可能会导致在不同子网中应答的页面。
Consider the following example. Suppose we have a network in which there are two paging areas, PA(1) and PA(2). Within each, there are many subnets. Consider a mobile that moves from PA(1) to PA(2), and enters PA(2) at subnet X. Using the paging area registration, it signals the network that it has moved, and suppose that the paging area registration contains a Mobile IP registration. The agent handling the L2 paging protocol sends the registration to the home/hierarchical agent (or perhaps it simply gets routed). The home/hierarchical agent now knows that the mobile has a CoA in subnet X, as does the mobile. After the mobile has completed the paging area registration/Mobile IP registration, it goes back to sleep.
考虑下面的例子。假设我们有一个网络，其中有两个分页区域，PA（1）和PA（2）。在每个子网中，都有许多子网。考虑从PA（1）移动到PA（2）的移动电话，并在子网X进入PA（2）。使用寻呼区域注册，它向其移动的网络发出信号，并假设寻呼区域注册包含移动IP注册。处理L2分页协议的代理将注册发送到主/分层代理（或者可能只是路由）。家庭/分层代理现在知道移动设备在子网X中有CoA，移动设备也是如此。移动设备完成寻呼区域注册/移动IP注册后，将返回睡眠状态。
But the mobile does not stop in subnet X, it keeps moving while in dormant mode, when it is doing no signaling (L2, mobile IP or other) to the network. It moves from subnet X where it originally entered the paging area clear to the other side of the paging area, in a completely different subnet, subnet Y.
但是移动设备并没有在子网X中停止，而是在休眠模式下继续移动，同时不向网络发送信号（L2、移动IP或其他）。它从最初进入寻呼区域的子网X移动到寻呼区域的另一侧，位于完全不同的子网Y中。
Suppose a packet comes into the home/hierarchical agent for this mobile. Because the home/hierarchical agent believes the mobile is in subnet X, it sends the packet to the access router or foreign agent for subnet X. The packet gets to the access router or foreign agent, and the access router or foreign agent performs a radio page for the mobile in subnet X. Since the mobile isn't in subnet X, it wakes up in subnet Y because the radio page propagates throughout the paging area. It does a mobile IP re-registration because it sees that it is in a new subnet, but the packet at the access router or foreign agent in subnet X can't get to the mobile.
假设一个数据包进入该移动设备的主/分层代理。因为主/分层代理认为移动设备位于子网X中，所以它将数据包发送到子网X的接入路由器或外部代理。数据包到达接入路由器或外部代理，并且接入路由器或外部代理在子网X中为移动设备执行无线寻呼。因为移动设备不在子网X中，它在子网Y中唤醒，因为无线页面在整个寻呼区域中传播。它执行移动IP重新注册，因为它看到它位于新的子网中，但子网X中的访问路由器或外部代理处的数据包无法到达移动设备。
Without any further support, the access router or foreign agent in subnet X drops the packet. The only way to get the packet to the mobile node from the access router or foreign agent is for the mobile node to send a binding update to the access router or foreign agent when it wakes up in the new subnet. Once the access router or foreign agent has the new binding, it can forward the packet. Some smooth handoff techniques depend on sending binding updates to foreign agents [5], so arranging for the mobile node to send a
在没有任何进一步支持的情况下，子网X中的访问路由器或外部代理会丢弃数据包。从接入路由器或外部代理向移动节点获取数据包的唯一方法是，移动节点在新子网中唤醒时向接入路由器或外部代理发送绑定更新。一旦接入路由器或外部代理具有新绑定，它就可以转发数据包。一些平滑切换技术依赖于向外部代理发送绑定更新[5]，因此安排移动节点发送绑定更新
binding update would be possible. In IPv6, it becomes less attractive because of the need for security on the binding update. In either case, the result would be yet more Mobile IP signaling before the packet could be delivered, increasing the amount of latency experienced by the mobile.
绑定更新是可能的。在IPv6中，由于需要绑定更新的安全性，它变得不那么吸引人。在任何一种情况下，结果都将是在分组可以被传送之前产生更多的移动IP信令，从而增加移动设备所经历的延迟量。
While it may be possible with enhancements to Mobile IP to handle the case, the enhancements would probably introduce more latency and signaling into the initial connection between the mobile and the network when the mobile awakes from dormant mode. An IP paging protocol between the home or hierarchical agent and a paging agent in the paging area would serve to reduce the amount of latency involved in delivering the initial packet. With IP paging, the arrival of the packet at the home/hierarchical agent results in an IP page to a paging agent in the last reported paging area. The paging agent performs an L2 page to the mobile. The mobile answers the page with a mobile IP registration to the home/hierarchical agent and the home/hierarchical agent sends the packet. The home/hierarchical agent and the mobile already have a security association, so there is no need to negotiate one, and buffering of the first packet and any further incoming packets prior to the mobile IP registration is handled by the home/hierarchical agent rather than a router at the edge, so the edge routers can be simpler. Finally, the home/hierarchical agent can start routing to the mobile as soon as the registration comes in.
虽然通过对移动IP的增强可以处理这种情况，但是当移动设备从休眠模式唤醒时，增强可能会在移动设备和网络之间的初始连接中引入更多的延迟和信令。归属或分层代理与寻呼区域中的寻呼代理之间的IP寻呼协议将用于减少传递初始数据包所涉及的延迟量。对于IP寻呼，数据包到达主/分层代理时，会在最后报告的寻呼区域向寻呼代理发送一个IP页面。寻呼代理向移动设备执行L2寻呼。移动设备向归属/分层代理应答具有移动IP注册的页面，并且归属/分层代理发送分组。归属/分层代理和移动设备已经具有安全关联，因此不需要协商安全关联，并且在移动IP注册之前，第一分组和任何进一步的传入分组的缓冲由归属/分层代理而不是边缘的路由器来处理，因此边缘路由器可以更简单。最后，注册一进来，归属/分层代理就可以开始路由到移动设备。
Up until now, the discussion has not identified any case where the problem of locating and delivering the first packet to a dormant mode mobile could not be handled by Mobile IP with enhancements. IP paging serves as a promising optimization in the multiple subnets to single paging area case, but in principle additional Mobile IP signaling (potentially lots in the case of IPv6 if a security association is needed) could handle the problem. However, the examples examined in the above sections are really best-case. In practice, the mapping of subnets to paging areas is likely to be far less clear cut, and the use of paging area registrations far less common than has been assumed in these cases.
到目前为止，讨论还没有发现任何情况下，通过增强的移动IP无法处理定位第一个数据包并将其传送到休眠模式移动设备的问题。在多个子网到单个寻呼区域的情况下，IP寻呼是一种很有前景的优化，但原则上，额外的移动IP信令（如果需要安全关联，在IPv6情况下可能是lots）可以处理该问题。然而，以上各节中的示例实际上是最好的例子。在实践中，子网到寻呼区域的映射可能远没有那么清晰，寻呼区域注册的使用远没有在这些情况下假设的那么普遍。
Requiring network operators to make paging areas and subnets conform to a subset relationship that would allow mobile IP signaling to do double duty as paging area updates is unrealistic. In practice, paging areas often overlap and there is often not even a clear subset relationship between paging areas themselves. Some radio protocols, such as wCDMA [6], allow different mobile terminals in the same geographical area to have different paging area identifiers. Working through each case and trying to identify whether Mobile IP needs
要求网络运营商使寻呼区域和子网符合子集关系，从而允许移动IP信令在寻呼区域更新时承担双重职责，这是不现实的。实际上，分页区域经常重叠，而且分页区域之间往往没有明确的子集关系。一些无线电协议，如wCDMA[6]，允许同一地理区域中的不同移动终端具有不同的寻呼区域标识符。处理每个案例并尝试确定移动IP是否需要
enhancement would probably result in a much more complex result than having a simple IP paging protocol that allows a home/hierarchical agent to notify an L2 agent in the paging area when a new packet comes in.
增强可能会导致比使用简单的IP分页协议更复杂的结果，该协议允许主/分层代理在新数据包进入时通知分页区域中的L2代理。
Finally, requiring operators to always turn on paging area registrations is unacceptable, and using Mobile IP registrations won't work if paging area registrations are not done. The above description is ideal with regard to signaling between the mobile node in dormant mode and the network. Anecdotal evidence indicates that most operators do not turn on paging area registrations, they use heuristics to determine where to page for the mobile. If the operator does not turn on paging area registrations, there is no way for the mobile to report its position when it changes paging area, hence no L2 vehicle for potential dormant mode use of Mobile IP.
最后，要求运营商始终打开寻呼区域注册是不可接受的，如果不进行寻呼区域注册，使用移动IP注册将不起作用。上述描述对于处于休眠模式的移动节点与网络之间的信令是理想的。传闻证据表明，大多数运营商不启用寻呼区域注册，而是使用启发式方法来确定移动设备的寻呼位置。如果运营商未打开寻呼区域注册，则移动设备在更改寻呼区域时无法报告其位置，因此没有L2车辆可用于移动IP的潜在休眠模式使用。
In a network composed of links with multiple technologies, the problems identified above become multiplied. Using Mobile IP becomes even more cumbersome, because the subnet to which the initial packet is delivered, besides not being in the same subnet on which the dormant mode mobile is located, may be on a radio network which the user would actually not prefer to use in their current location. This could happen, for example, if the mobile moved inside a building and radio coverage on one interface became weak or nonexistent, or if the user had a choice of a cheaper or higher bandwidth connection. The mobile may actually no longer be listening or reachable on the paging channel of the old network, so when the old access router or foreign agent pages on the old radio network, the mobile, which is now listening only for pages on the new network, may not answer, even though it is reachable on the new network. Arranging for pages in multiple radio networks is a possibility, but without an L3 paging protocol to abstract away from the L2 details, the details of each L2 protocol must be handled separately.
在由具有多种技术的链路组成的网络中，上述问题会成倍增加。使用移动IP变得更加麻烦，因为初始分组被传送到的子网除了不在休眠模式移动设备所在的同一子网中之外，还可能位于用户实际上不愿意在其当前位置使用的无线网络上。例如，如果移动设备在建筑物内移动，并且一个接口上的无线电覆盖变弱或不存在，或者如果用户可以选择更便宜或更高带宽的连接，则可能发生这种情况。移动设备实际上可能不再在旧网络的寻呼信道上侦听或可访问，因此，当旧的接入路由器或外部代理在旧的无线网络上寻呼时，现在只侦听新网络上的寻呼的移动设备可能不会应答，即使它在新网络上可访问。可以在多个无线网络中安排页面，但如果没有L3寻呼协议从L2细节中抽象出来，则必须单独处理每个L2协议的细节。
A paging protocol that unifies paging across multiple radio technologies therefore looks attractive. There may be commonalities in the corresponding radio paging protocols that allow a mapping to be established between the radio protocols and an abstract IP paging protocol. For example, assume we have a common paging area identifier defined at the IP layer that is mapped to each radio paging protocol by the access points. An IP paging message containing the identifier is sent to multiple access points, where the appropriate radio paging message is sent based on the particular technology implemented by the access points. The results are then returned by the radio paging responses, mapped back into IP by the access points, and delivered back to the origin of the page.
因此，将多种无线电技术中的寻呼统一起来的寻呼协议看起来很有吸引力。相应的无线寻呼协议中可能存在共同点，允许在无线协议和抽象IP寻呼协议之间建立映射。例如，假设我们在IP层定义了一个公共寻呼区域标识符，该标识符由接入点映射到每个无线寻呼协议。将包含标识符的IP寻呼消息发送到多个接入点，在这些接入点中，根据接入点实现的特定技术发送适当的无线寻呼消息。然后，结果由无线寻呼响应返回，由接入点映射回IP，并传递回页面的源。
An additional case to consider is when a single subnet consists of multiple radio access technologies. A wireless access point usually provides L2 bridge behavior to the wired link with which it is connected. If two access points with incompatible technologies and non-overlapping cells are connected to the same subnet, a mobile node with interfaces to both technologies would need paging from both technologies. If reachability can be established simply by ARP or neighbor discovery, no IP paging is needed. However, note that ARP or neighbor discovery requires that a functional traffic channel be available to the mobile, since these protocols are typically implemented for wired networks in which a single channel exists on which all IP traffic is delivered. If the mobile is currently in the sleep phase of a time-slotted dormant mode, or if it is listening to a paging channel it will fail to respond to these requests. In this case, some means of triggering a radio page from IP is necessary to find the mobile. Modifying ARP or neighbor discovery to utilize a paging channel if available is a possible, if somewhat messy, alternative, but a dedicated location protocol may be somewhat cleaner.
要考虑的另一个情况是当单个子网由多个无线电接入技术组成时。无线接入点通常向与其连接的有线链路提供L2网桥行为。如果两个具有不兼容技术和非重叠小区的接入点连接到同一子网，则具有这两种技术接口的移动节点将需要来自这两种技术的寻呼。如果仅通过ARP或邻居发现就可以建立可达性，则不需要IP寻呼。然而，请注意，ARP或邻居发现要求功能性业务信道可供移动设备使用，因为这些协议通常用于有线网络，其中存在一个信道，所有IP业务在该信道上传输。如果移动设备当前处于时隙休眠模式的休眠阶段，或者如果它正在侦听寻呼信道，它将无法响应这些请求。在这种情况下，需要一些从IP触发无线电页面的方法来查找移动设备。修改ARP或邻居发现以利用寻呼信道（如果可用的话）是一种可能的（如果有点混乱的话）替代方案，但专用位置协议可能更干净一些。
If the Seamoby Working Group decides that an IP micromobility protocol is necessary, then the above analysis is no longer complete. A micromobility protocol may require some type of paging support. The design team does not want to include any further discussion of paging and micromobility at this point, because it is not clear whether micromobility will be pursued by Seamoby and hence such discussion would be premature.
如果Seamoby工作组决定需要IP微移动协议，则上述分析不再完整。微移动协议可能需要某种类型的分页支持。此时，设计团队不想进一步讨论寻呼和微移动，因为目前尚不清楚Seamoby是否会追求微移动，因此此类讨论为时过早。
While the above analysis has identified situations in which location of a mobile in dormant mode may require some action at the IP layer, it is important keep in mind what the problem is. The problem to be solved is the location of a mobile node because it has moved while in dormant mode. IP paging is one solution to the problem, there may be others.
虽然上述分析已经确定了在休眠模式下移动设备的定位可能需要在IP层采取一些措施的情况，但重要的是要记住问题所在。要解决的问题是移动节点的位置，因为它在休眠模式下移动。IP寻呼是解决这个问题的一种方法，可能还有其他方法。
The design group recommends the following charter items for Seamboy:
设计小组为Seamboy推荐以下特许项目：
1) Since the design group has identified several network deployment scenarios where existing Mobile IP technology cannot find a mobile in dormant mode, protocol work is necessary to define a way for the network to find a mobile that is currently in dormant mode.
1) 由于设计小组已经确定了几个网络部署场景，其中现有的移动IP技术无法找到处于休眠模式的移动设备，因此需要进行协议工作，以确定网络找到当前处于休眠模式的移动设备的方法。
2) The work defined above should be pursued in a way that is maximally consistent with Mobile IP and other existing IETF protocols. The work should also generate recommendations about how to achieve the best match between existing radio paging protocols and IP.
2) 上述工作应以与移动IP和其他现有IETF协议最大程度一致的方式进行。这项工作还应该产生关于如何在现有无线寻呼协议和IP之间实现最佳匹配的建议。
3) If the Seamoby working group decides to pursue a micromobility protocol that requires paging, the Seamoby group should undertake the design of a new paging protocol within the context of that work.
3) 如果Seamoby工作组决定采用需要寻呼的微移动协议，Seamoby工作组应在该工作范围内设计新的寻呼协议。
4) There is some evidence that cellular operators' deployments of paging are highly variable, and may, in fact, be suboptimal in many cases with respect to supporting IP. The Seamoby working group should write a BCP which explains how to perform IP subnet to paging area mapping and which techniques to use when, so network designers in wireless networks have a guide when they are setting up their networks.
4) 有一些证据表明，蜂窝网络运营商的寻呼部署是高度可变的，事实上，在许多情况下，在支持IP方面可能是次优的。Seamoby工作组应编写一份BCP，解释如何执行IP子网到寻呼区域的映射以及何时使用哪些技术，以便无线网络中的网络设计师在设置网络时提供指导。
The editor would like to thank the Seamoby paging design team for helping formulate the first draft of the document. Jari Malinen contributed text to Section 4.2. Hesham Soliman, Karim El-Malki, and Behcet Sarikaya contributed critical commentary on the first draft, which was important in sharpening the reasoning about what can and can't be expected in the absence of radio layer paging support and how Mobile IP might be used to support dormant mode location.
编辑要感谢Seamoby页面设计团队帮助制定了该文件的初稿。Jari Malinen为第4.2节提供了文本。Hesham Soliman、Karim El-Malki和Behcet Sarikaya对初稿做出了批评性评论，这对于阐明在没有无线层寻呼支持的情况下可以预期什么和不可以预期什么以及如何使用移动IP支持休眠模式定位具有重要意义。
[1] Perkins, C., Editor, "IP Mobility Support", RFC 2002, October 1996.
[1] Perkins，C.，编辑，“IP移动支持”，RFC 2002，1996年10月。
[2] Johnson, D., and C. Perkins, "Mobility Support in IPv6", Work in Progress.
[2] Johnson，D.和C.Perkins，“IPv6中的移动支持”，正在进行中。
[3] El Malki, K. et. al., "Low Latency Handoff in Mobile IPv4", Work in Progress.
[3] El Malki，K.等人，“移动IPv4中的低延迟切换”，正在进行中。
[4] Tsirtsis, G., Editor, "Fast Handovers for Mobile IPv6", Work in Progress.
[4] Tsirtsis，G.，编辑，“移动IPv6的快速切换”，正在进行中。
[5] Perkins, C. and D. Johnson, "Route Optimization in Mobile IP", Work in Progress.
[5] Perkins，C.和D.Johnson，“移动IP中的路由优化”，正在进行中。
[6] Holma, H. and A. Toskala, "WCDMA for UMTS: Radio Access for Third Generation Mobile Communication", John Wiley and Sons, New York, 2000.
[6] Holma，H.和A.Toskala，“UMTS的WCDMA：第三代移动通信的无线电接入”，John Wiley和Sons，纽约，2000年。
James Kempf Sun Labs California Sun Microsystems, Inc. 901 San Antonio Rd., UMPK15-214 Palo Alto, CA, 94303 USA
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Acknowledgement
确认
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