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diff --git a/doc/rfc/rfc3132.txt b/doc/rfc/rfc3132.txt new file mode 100644 index 0000000..ecc58f5 --- /dev/null +++ b/doc/rfc/rfc3132.txt @@ -0,0 +1,787 @@ + + + + + + +Network Working Group J. Kempf +Request for Comments: 3132 Sun Microsystems +Category: Informational June 2001 + + + Dormant Mode Host Alerting ("IP Paging") Problem Statement + +Status of this Memo + + This memo provides information for the Internet community. It does + not specify an Internet standard of any kind. Distribution of this + memo is unlimited. + +Copyright Notice + + Copyright (C) The Internet Society (2001). All Rights Reserved. + +Abstract + + 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. + +1.0 Introduction + + 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. + + 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. + + + + + +Kempf Informational [Page 1] + +RFC 3132 Dormant Mode Host Alerting Problem Statement June 2001 + + + 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. + + 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. + +2.0 Definitions + + The following definitions are relevant with respect to clarifying the + paging functionality: + + 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. + + 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. + + 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. + + 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. + + + +Kempf Informational [Page 2] + +RFC 3132 Dormant Mode Host Alerting Problem Statement June 2001 + + + 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). + + 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. + + 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. + +3.0 Discussion of Paging + + Dormant mode is advantageous to a mobile node and the network for the + following reasons: + + - 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. + + - 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. + + 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. + + + + + + + + +Kempf Informational [Page 3] + +RFC 3132 Dormant Mode Host Alerting Problem Statement June 2001 + + +3.1 Dormant Mode Support Only + + 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. + + 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. + + 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. + +3.2 Dormant Mode with Paging Support + + 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. + + 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. + + 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. + + + +Kempf Informational [Page 4] + +RFC 3132 Dormant Mode Host Alerting Problem Statement June 2001 + + + 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. + +4.0 Is IP Paging Necessary? + + 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. + +4.1 IP Paging for Dormant Mode Only Radio Links + + 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. + + 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. + + 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 + + + +Kempf Informational [Page 5] + +RFC 3132 Dormant Mode Host Alerting Problem Statement June 2001 + + + 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. + + As a consequence, IP paging provides no advantages for radio link + protocols in which the radio link does not have support for paging. + +4.2 IP Paging for Radio Links with Paging Support + + 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. + +4.2.1 Homogeneous Technology Networks + + 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. + + 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. + + 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 + + + + +Kempf Informational [Page 6] + +RFC 3132 Dormant Mode Host Alerting Problem Statement June 2001 + + + 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. + + There are three cases: + + 1) The topological boundaries of the paging area and subnet are + identical. + + 2) Multiple paging areas are part of the same subnet. + + 3) Multiple subnets are part of the same paging area. + + Each case is considered in the following subsections. + +4.2.1.1 Subnet and Paging Area Boundaries Identical + + 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. + +4.2.1.2 Multiple Paging Areas Map into One Subnet + + 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. + + + + + + + + +Kempf Informational [Page 7] + +RFC 3132 Dormant Mode Host Alerting Problem Statement June 2001 + + +4.2.1.3 Multiple Subnets Map into One Paging Area + + 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. + + 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. + + 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. + + 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. + + 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 + + + +Kempf Informational [Page 8] + +RFC 3132 Dormant Mode Host Alerting Problem Statement June 2001 + + + 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. + + 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. + +4.1.2.4 More Complex Homogeneous Network Cases + + 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. + + 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 + + + +Kempf Informational [Page 9] + +RFC 3132 Dormant Mode Host Alerting Problem Statement June 2001 + + + 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. + + 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. + +4.2.2 Heterogeneous Technology Networks + + 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. + + 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. + + + +Kempf Informational [Page 10] + +RFC 3132 Dormant Mode Host Alerting Problem Statement June 2001 + + + 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. + +4.3 Paging and Micromobility + + 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. + +5.0 What Exactly is the Problem? + + 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. + +6.0 Recommendations + + The design group recommends the following charter items for Seamboy: + + 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. + + + +Kempf Informational [Page 11] + +RFC 3132 Dormant Mode Host Alerting Problem Statement June 2001 + + + 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. + + 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. + + 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. + +7.0 Acknowledgements + + 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. + + + + + + + + + + + + + + + + + + + + + + +Kempf Informational [Page 12] + +RFC 3132 Dormant Mode Host Alerting Problem Statement June 2001 + + +8.0 References + + [1] Perkins, C., Editor, "IP Mobility Support", RFC 2002, October + 1996. + + [2] Johnson, D., and C. Perkins, "Mobility Support in IPv6", Work in + Progress. + + [3] El Malki, K. et. al., "Low Latency Handoff in Mobile IPv4", Work + in Progress. + + [4] Tsirtsis, G., Editor, "Fast Handovers for Mobile IPv6", Work in + Progress. + + [5] Perkins, C. and D. Johnson, "Route Optimization in Mobile IP", + Work in Progress. + + [6] Holma, H. and A. Toskala, "WCDMA for UMTS: Radio Access for + Third Generation Mobile Communication", John Wiley and Sons, New + York, 2000. + +9.0 Editor's Address + + James Kempf + Sun Labs California + Sun Microsystems, Inc. + 901 San Antonio Rd., UMPK15-214 + Palo Alto, CA, 94303 + USA + + Phone: +1 650 786 5890 + Fax: +1 650 786 6445 + EMail: james.kempf@sun.com + + + + + + + + + + + + + + + + + + +Kempf Informational [Page 13] + +RFC 3132 Dormant Mode Host Alerting Problem Statement June 2001 + + +10.0 Full Copyright Statement + + Copyright (C) The Internet Society (2001). All Rights Reserved. + + This document and translations of it may be copied and furnished to + others, and derivative works that comment on or otherwise explain it + or assist in its implementation may be prepared, copied, published + and distributed, in whole or in part, without restriction of any + kind, provided that the above copyright notice and this paragraph are + included on all such copies and derivative works. However, this + document itself may not be modified in any way, such as by removing + the copyright notice or references to the Internet Society or other + Internet organizations, except as needed for the purpose of + developing Internet standards in which case the procedures for + copyrights defined in the Internet Standards process must be + followed, or as required to translate it into languages other than + English. + + The limited permissions granted above are perpetual and will not be + revoked by the Internet Society or its successors or assigns. + + This document and the information contained herein is provided on an + "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING + TASK FORCE DISCLAIMS 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. + +Acknowledgement + + Funding for the RFC Editor function is currently provided by the + Internet Society. + + + + + + + + + + + + + + + + + + + +Kempf Informational [Page 14] + |