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rfc:rfc3753

Network Working Group J. Manner, Ed. Request for Comments: 3753 M. Kojo, Ed. Category: Informational June 2004

                    Mobility Related Terminology

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 (2004).

Abstract

 There is a need for common definitions of terminology in the work to
 be done around IP mobility.  This document defines terms for mobility
 related terminology.  The document originated out of work done in the
 Seamoby Working Group but has broader applicability for terminology
 used in IETF-wide discourse on technology for mobility and IP
 networks.  Other working groups dealing with mobility may want to
 take advantage of this terminology.

Table of Contents

 1.  Introduction. . . . . . . . . . . . . . . . . . . . . . . . .   2
 2.  General Terms . . . . . . . . . . . . . . . . . . . . . . . .   2
 3.  Mobile Access Networks and Mobile Networks. . . . . . . . . .  10
 4.  Handover Terminology. . . . . . . . . . . . . . . . . . . . .  15
     4.1.  Scope of Handover . . . . . . . . . . . . . . . . . . .  16
     4.2.  Handover Control. . . . . . . . . . . . . . . . . . . .  17
     4.3.  Simultaneous connectivity to Access Routers . . . . . .  19
     4.4.  Performance and Functional Aspects. . . . . . . . . . .  19
     4.5.  Micro Diversity, Macro Diversity, and IP Diversity. . .  21
     4.6.  Paging, and Mobile Node States and Modes. . . . . . . .  22
     4.7.  Context Transfer. . . . . . . . . . . . . . . . . . . .  24
     4.8.  Candidate Access Router Discovery . . . . . . . . . . .  24
     4.9.  Types of Mobility . . . . . . . . . . . . . . . . . . .  25
 5.  Specific Terminology for Mobile Ad-Hoc Networking . . . . . .  26
 6.  Security-related Terminology. . . . . . . . . . . . . . . . .  27
 7.  Security Considerations . . . . . . . . . . . . . . . . . . .  28
 8.  Contributors. . . . . . . . . . . . . . . . . . . . . . . . .  28
 9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  29
 10. Informative References. . . . . . . . . . . . . . . . . . . .  29

Manner & Kojo Informational [Page 1] RFC 3753 Mobility Related Terminology June 2004

 11. Appendix A - Index of Terms . . . . . . . . . . . . . . . . .  31
 12. Authors' Addresses. . . . . . . . . . . . . . . . . . . . . .  35
 13. Full Copyright Statement. . . . . . . . . . . . . . . . . . .  36

1. Introduction

 This document presents terminology to be used for documents and
 discussions within the Seamoby Working Group.  Other mobility related
 working groups could take advantage of this terminology, in order to
 create a common terminology for the area of mobility in IP networks.
 Some terms and their definitions that are not directly related to the
 IP world are included for the purpose of harmonizing the terminology.
 For example, 'Access Point' and 'base station' refer to the same
 component, from the point of view of IP, but 'Access Router' has a
 very different meaning.  The presented terminology may also, it is
 hoped, be adequate to cover mobile ad-hoc networks.
 The proposed terminology is not meant to assert any new terminology.
 Rather the authors would welcome discussion on more exact definitions
 as well as missing or unnecessary terms.  This work is a
 collaborative enterprise between people from many different
 engineering backgrounds and so already presents a first step in
 harmonizing the terminology.
 The terminology in this document is divided into several sections.
 First, there is a list of terms for general use and mobile access
 networks followed by terms related to handovers, and finally some
 terms used within the MANET and NEMO working groups.

2. General Terms

 Bandwidth
    The total width of the frequency band available to or used by a
    communications channel.  Usually measured in Hertz (Hz).  The
    bandwidth of a channel limits the available channel capacity.
 Bandwidth utilization
    The actual rate of information transfer achieved over a link,
    expressed as a percentage of the theoretical maximum channel
    capacity on that link, according to Shannon's Law.

Manner & Kojo Informational [Page 2] RFC 3753 Mobility Related Terminology June 2004

 Beacon
    A control message broadcast by a node (especially, a base station)
    informing all the other nodes in its neighborhood of the
    continuing presence of the broadcasting node, possibly along with
    additional status or configuration information.
 Binding Update (BU)
    A message indicating a mobile node's current mobility binding, and
    in particular its care-of address.
 Care-of-Address (CoA)
    An IP address associated with a mobile node while visiting a
    foreign link; the subnet prefix of this IP address is a foreign
    subnet prefix.  A packet addressed to the mobile node which
    arrives at the mobile node's home network when the mobile node is
    away from home and has registered a Care-of Address will be
    forwarded to that address by the Home Agent in the home network.
 Channel
    A subdivision of the physical medium allowing possibly shared
    independent uses of the medium.  Channels may be made available by
    subdividing the medium into distinct time slots, or distinct
    spectral bands, or decorrelated coding sequences.
 Channel access protocol
    A protocol for mediating access to, and possibly allocation of,
    the various channels available within the physical communications
    medium.  Nodes participating in the channel access protocol agree
    to communicate only when they have uncontested access to one of
    the channels, so that there will be no interference.
 Channel capacity
    The total capacity of a link to carry information (typically bits)
    per unit time.  With a given bandwidth, the theoretical maximum
    channel capacity is given by Shannon's Law.  The actual channel
    capacity of a channel is determined by the channel bandwidth, the
    coding system used, and the signal to noise ratio.

Manner & Kojo Informational [Page 3] RFC 3753 Mobility Related Terminology June 2004

 Control message
    Information passed between two or more network nodes for
    maintaining protocol state, which may be unrelated to any specific
    application.
 Distance vector
    A characteristic of some routing protocols in which, for each
    desired destination, a node maintains information about the
    distance to that destination, and a vector (next hop) towards that
    destination.
 Fairness
    A property of channel access protocols whereby a medium is made
    fairly available to all eligible nodes on the link.  Fairness does
    not strictly imply equality, especially in cases where nodes are
    given link access according to unequal priority or classification.
 Flooding
    The process of delivering data or control messages to every node
    within the network under consideration.
 Foreign subnet prefix
    A bit string that consists of some number of initial bits of an IP
    address which identifies a node's foreign link within the Internet
    topology.
 Forwarding node
    A node which performs the function of forwarding datagrams from
    one of its neighbors to another.
 Home Address (HoA)
    An IP address assigned to a mobile node, used as the permanent
    address of the mobile node.  This address is within the mobile
    node's home link.  Standard IP routing mechanisms will deliver
    packets destined for a mobile node's home address to its home link
    [9].

Manner & Kojo Informational [Page 4] RFC 3753 Mobility Related Terminology June 2004

 Home Agent (HA)
    A router on a mobile node's home link with which the mobile node
    has registered its current care-of address.  While the mobile node
    is away from home, the home agent intercepts packets on the home
    link destined to the mobile node's home address, encapsulates
    them, and tunnels them to the mobile node's registered care-of
    address.
 Home subnet prefix
    A bit string that consists of some number of initial bits of an IP
    address which identifies a node's home link within the Internet
    topology (i.e., the IP subnet prefix corresponding to the mobile
    node's home address, as defined in [9]).
 Interface
    A node's point of attachment to a link.
 IP access address
    An IP address (often dynamically allocated) which a node uses to
    designate its current point of attachment to the local network.
    The IP access address is typically to be distinguished from the
    mobile node's home address; in fact, while visiting a foreign
    network the IP access address may be considered unsuitable for use
    as an end-point address by any but the most short-lived
    applications.  Instead, the IP access address is typically used as
    the care-of address of the node.
 Link
    A communication facility or physical medium that can sustain data
    communications between multiple network nodes, such as an Ethernet
    (simple or bridged).  A link is the layer immediately below IP.
    In a layered network stack model, the Link Layer (Layer 2) is
    normally below the Network (IP) Layer (Layer 3), and above the
    Physical Layer (Layer 1).
 Asymmetric link
    A link with transmission characteristics which are different
    depending upon the relative position or design characteristics of
    the transmitter and the receiver of data on the link.  For
    instance, the range of one transmitter may be much higher than the
    range of another transmitter on the same medium.

Manner & Kojo Informational [Page 5] RFC 3753 Mobility Related Terminology June 2004

 Link establishment
    The process of establishing a link between the mobile node and the
    local network.  This may involve allocating a channel, or other
    local wireless resources, possibly including a minimum level of
    service or bandwidth.
 Link-layer trigger (L2 Trigger)
    Information from the link layer that informs the network layer of
    the detailed events involved in handover sequencing at the link
    layer.  L2 triggers are not specific to any particular link layer,
    but rather represent generalizations of link layer information
    available from a wide variety of link layer protocols [4].
 Link state
    A characterization of some routing protocols in which every node
    within the network is expected to maintain information about every
    link within the network topology.
 Link-level acknowledgment
    A protocol strategy, typically employed over wireless media,
    requiring neighbors to acknowledge receipt of packets (typically
    unicast only) from the transmitter.  Such strategies aim to avoid
    packet loss or delay resulting from lack of, or unwanted
    characteristics of, higher level protocols.  Link-layer
    acknowledgments are often used as part of Automatic Repeat-Request
    (ARQ) algorithms for increasing link reliability.
 Local broadcast
    The delivery of data to every node within range of the
    transmitter.
 Loop-free
    A property of routing protocols whereby the path taken by a data
    packet from source to destination never traverses through the same
    intermediate node twice before arrival at the destination.

Manner & Kojo Informational [Page 6] RFC 3753 Mobility Related Terminology June 2004

 Medium Access Protocol (MAC)
    A protocol for mediating access to, and possibly allocation of,
    the physical communications medium.  Nodes participating in the
    medium access protocol can communicate only when they have
    uncontested access to the medium, so that there will be no
    interference.  When the physical medium is a radio channel, the
    MAC is the same as the Channel Access Protocol.
 Mobile network prefix
    A bit string that consists of some number of initial bits of an IP
    address which identifies the entire mobile network within the
    Internet topology.  All nodes in a mobile network necessarily have
    an address containing this prefix.
 Mobility factor
    The relative frequency of node movement, compared to the frequency
    of application initiation.
 Multipoint relay (MPR)
    A node which is selected by its one-hop neighbor to re-transmit
    all broadcast messages that it receives.  The message must be new
    and the time-to-live field of the message must be greater than
    one.  Multipoint relaying is a technique to reduce the number of
    redundant re-transmissions while diffusing a broadcast message in
    the network.
 Neighbor
    A "neighbor" is any other node to which data may be propagated
    directly over the communications medium without relying on the
    assistance of any other forwarding node.
 Neighborhood
    All the nodes which can receive data on the same link from one
    node whenever it transmits data.
 Next hop
    A neighbor which has been selected to forward packets along the
    way to a particular destination.

Manner & Kojo Informational [Page 7] RFC 3753 Mobility Related Terminology June 2004

 Payload
    The actual data within a packet, not including network protocol
    headers which were not inserted by an application.  Note that
    payloads are different between layers:  application data is the
    payload of TCP, which are the payload of IP, which three are the
    payload of link layer protocols etc.  Thus, it is important to
    identify the scope when talking about payloads.
 Prefix
    A bit string that consists of some number of initial bits of an
    address.
 Routing table
    The table where forwarding nodes keep information (including next
    hop) for various destinations.
 Route entry
    An entry for a specific destination (unicast or multicast) in the
    routing table.
 Route establishment
    The process of determining a route between a source and a
    destination.
 Route activation
    The process of putting a route into use after it has been
    determined.
 Routing proxy
    A node that routes packets by overlays, e.g., by tunneling,
    between communicating partners.  The Home Agent and Foreign Agent
    are examples of routing proxies, in that they receive packets
    destined for the mobile node and tunnel them to the current
    address of the mobile node.

Manner & Kojo Informational [Page 8] RFC 3753 Mobility Related Terminology June 2004

 Shannon's Law
    A statement defining the theoretical maximum rate at which error-
    free digits can be transmitted over a bandwidth-limited channel in
    the presence of noise.  No practical error correction coding
    system exists that can closely approach the theoretical
    performance limit given by Shannon's law.
 Signal strength
    The detectable power of the signal carrying the data bits, as seen
    by the receiver of the signal.
 Source route
    A source route from node A to node B is an ordered list of IP
    addresses, starting with the IP address of node A and ending with
    the IP address of the node B.  Between A and B, the source route
    includes an ordered list of intermediate hops between A and B, as
    well as the interface index of the interface through which the
    packet should be transmitted to reach the next hop.  The list of
    intermediate hops might not include all visited nodes, some hops
    might be omitted for a reason or another.
 Spatial re-use
    Simultaneous use of channels with identical or close physical
    characteristics, but located spatially far enough apart to avoid
    interference (i.e., co-channel interference)
 System-wide broadcast
    Same as flooding, but used in contrast to local broadcast.
 Subnet
    A subnet is a logical group of connected network nodes.  In IP
    networks, nodes in a subnet share a common network mask (in IPV4)
    or a network prefix (in IPv6).
 Topology (Network Topology)
    The interconnection structure of a network: which nodes are
    directly connected to each other, and through which links they are
    connected.  Some simple topologies have been given names, such as
    for instance 'bus topology', 'mesh topology', 'ring topology',
    'star topology' and 'tree topology'.

Manner & Kojo Informational [Page 9] RFC 3753 Mobility Related Terminology June 2004

 Triggered update
    A solicited route update transmitted by a router along a path to a
    destination.

3. Mobile Access Networks and Mobile Networks

 In order to support host mobility a set of nodes towards the network
 edge may need to have specific functions.  Such a set of nodes forms
 a mobile access network that may or may not be part of the global
 Internet.  Figure 1 presents two examples of such access network
 topologies.  The figure depicts a reference architecture which
 illustrates an IP network with components defined in this section.
 We intend to define the concept of the Access Network (AN) which may
 also support enhanced mobility.  It is possible that to support
 routing and QoS for mobile nodes, existing routing protocols (e.g.,
 Open Shortest Path First (OSPF) [14]) may not be appropriate to
 maintain forwarding information for these mobile nodes as they change
 their points of attachment to the Access Network.  These new
 functions are implemented in routers with additional capabilities.
 We can distinguish three types of Access Network components: Access
 Routers (AR) which handle the last hop to the mobile, typically over
 a wireless link; Access Network Gateways (ANG) which form the
 boundary on the fixed network side and shield the fixed network from
 the specialized routing protocols; and (optionally) other internal
 Access Network Routers which may also be needed in some cases to
 support the functions.  The Access Network consists of the equipment
 needed to support this specialized routing, i.e., AR or ANG.  AR and
 ANG may be the same physical nodes.
 In addition, we present a few basic terms on mobile networks, that
 is, mobile network, mobile router (MR), and mobile network node
 (MNN).  More terminology for discussing mobile networks can be found
 in [13].  A more thorough discussion of mobile networks can be found
 in the working group documents of the NEMO Working Group.
 Note: this reference architecture is not well suited for people
 dealing with Mobile Ad-hoc Networks (MANET).

Manner & Kojo Informational [Page 10] RFC 3753 Mobility Related Terminology June 2004

                                                                 |
                                                                 |
                   ---        ------                    -------  |
      ---  | <-->  | | -------| AR | -------------------|     |  |
      | |--[]      ---        /------          \       /| ANG |--|
      ---            AP      /                  \     / |     |  |
       MH                   /                    \   /  -------  |
 (with wireless     ___    /                    -------          |
      device)       | |----                     | ANR |          |
                    ---                         -------          |
                     AP                          /   \           |
                                                /     \ -------  |
                   ---       ------            /       \|     |  |
                   | |-------| AR |---------------------| ANG |--|
                   ---       ------                     |     |  |
                    AP                                  -------  |
                                                                 |
                        Access Network (AN) 1                    |
 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  -|
                        Access Network (AN) 2                    |
                                                                 |
                                                                 |
                   ---        ------                    -------  |
     ---  | <-->   | | -------| AR | -------------------|     |  |
     | |--[]       ---       /------                   /| ANG |--|
     ---            AP      /                         / |     |  |
      MH                   /                         /  -------  |
 (with wireless    ___    /                         /            |
     device)       | |----                         /             |
                   ---                            /              |
                    AP                           /               |
                                                /                |
     |            ---       ------         -------               |
 --- |       | <->| |-------| AR |---------| ANR |               |
 | |-|      []    ---  \    ------         -------               |
 --- |  -----|     AP   \                  /                     |
 MNN |--i MR e           \                /                      |
     |  ------    ---     \ ------       /                       |
 --- | (with      | |-------| AR |-------                        |
 | |-| wireless   ---       ------                               |
 --- |  device)    AP                                            |
 MNN                                 'i': MR ingress interface   |
                                     'e': MR egress interface    |
                                                                 |
              Figure 1: Reference Network Architecture

Manner & Kojo Informational [Page 11] RFC 3753 Mobility Related Terminology June 2004

 Mobile Node (MN)
    An IP node capable of changing its point of attachment to the
    network.  A Mobile Node may either be a Mobile Host (no forwarding
    functionality) or a Mobile Router (forwarding functionality).
 Mobile Host (MH)
    A mobile node that is an end host and not a router.  A Mobile Host
    is capable of sending and receiving packets, that is, being a
    source or destination of traffic, but not a forwarder of it.
 Fixed Node (FN)
    A node, either a host or a router, unable to change its point of
    attachment to the network and its IP address without breaking open
    sessions.
 Mobile network
    An entire network, moving as a unit, which dynamically changes its
    point of attachment to the Internet and thus its reachability in
    the topology.  The mobile network is composed of one or more IP-
    subnets and is connected to the global Internet via one or more
    Mobile Routers (MR).  The internal configuration of the mobile
    network is assumed to be relatively stable with respect to the MR.
 Mobile Router (MR)
    A router capable of changing its point of attachment to the
    network, moving from one link to another link.  The MR is capable
    of forwarding packets between two or more interfaces, and possibly
    running a dynamic routing protocol modifying the state by which it
    does packet forwarding.
    A MR acting as a gateway between an entire mobile network and the
    rest of the Internet has one or more egress interface(s)  and one
    or more ingress interface(s).  Packets forwarded upstream to the
    rest of the Internet are transmitted through one of the MR's
    egress interface; packets forwarded downstream to the mobile
    network are transmitted through one of the MR's ingress interface.
 Ingress interface
    The interface of a MR attached to a link inside the mobile
    network.

Manner & Kojo Informational [Page 12] RFC 3753 Mobility Related Terminology June 2004

 Egress interface
    The interface of a MR attached to the home link if the MR is at
    home, or attached to a foreign link if the MR is in a foreign
    network.
 Mobile Network Node (MNN)
    Any node (host or router) located within a mobile network, either
    permanently or temporarily.  A Mobile Network Node may either be a
    mobile node or a fixed node.
 Access Link (AL)
    A last-hop link between a Mobile Node and an Access Point.  That
    is, a facility or medium over which an Access Point and the Mobile
    Node can communicate at the link layer, i.e., the layer
    immediately below IP.
 Access Point (AP)
    An Access Point is a layer 2 device which is connected to one or
    more Access Routers and offers the wireless link connection to the
    Mobile Node.  Access Points are sometimes called base stations or
    access point transceivers.  An Access Point may be a separate
    entity or co-located with an Access Router.
 Radio Cell
    The geographical area within which an Access Point provides radio
    coverage, i.e., where radio communication between a Mobile Node
    and the specific Access Point is possible.
 Access Network Router (ANR)
    An IP router in the Access Network.  An Access Network Router may
    include Access Network specific functionalities, for example,
    related to mobility and/or QoS.  This is to distinguish between
    ordinary routers and routers that have Access Network-related
    special functionality.

Manner & Kojo Informational [Page 13] RFC 3753 Mobility Related Terminology June 2004

 Access Router (AR)
    An Access Network Router residing on the edge of an Access Network
    and connected to one or more Access Points.  The Access Points may
    be of different technology.  An Access Router offers IP
    connectivity to Mobile Nodes, acting as a default router to the
    Mobile Nodes it is currently serving.  The Access Router may
    include intelligence beyond a simple forwarding service offered by
    ordinary IP routers.
 Access Network Gateway (ANG)
    An Access Network Router that separates an Access Network from
    other IP networks, much in the same way as an ordinary gateway
    router.  The Access Network Gateway looks to the other IP networks
    like a standard IP router.  In a small network, an ANG may also
    offer the services of an AR, namely offer the IP connectivity to
    the mobile nodes.
 Access Network (AN)
    An IP network which includes one or more Access Network Routers.
 Administrative Domain (AD)
    A collection of networks under the same administrative control and
    grouped together for administrative purposes [5].
 Serving Access Router (SAR)
    The Access Router currently offering the connectivity to the MN.
    This is usually the point of departure for the MN as it makes its
    way towards a new Access Router (at which time the Serving Access
    Router takes the role of the Previous Access Router).  There may
    be several Serving Access Routers serving the Mobile Node at the
    same time.
 New Access Router (NAR)
    The Access Router that offers connectivity to the Mobile Node
    after a handover.

Manner & Kojo Informational [Page 14] RFC 3753 Mobility Related Terminology June 2004

 Previous Access Router (PAR)
    An Access Router that offered connectivity to the Mobile Node
    prior to a handover.  This is the Serving Access Router that will
    cease or has ceased to offer connectivity to the Mobile Node.
    Often also called Old Access Router (OAR).
 Candidate Access Router (CAR)
    An Access Router to which the Mobile Node may do a handoff.  See
    Section 4.8.

4. Handover Terminology

 These terms refer to different perspectives and approaches to
 supporting different aspects of mobility.  Distinctions can be made
 according to the scope, range overlap, performance characteristics,
 diversity characteristics, state transitions, mobility types, and
 control modes of handover techniques.
 Roaming
    An operator-based term involving formal agreements between
    operators that allows a mobile to get connectivity from a foreign
    network.  Roaming (a particular aspect of user mobility) includes,
    for example, the functionality by which users can communicate
    their identity to the local AN so that inter-AN agreements can be
    activated and service and applications in the MN's home network
    can be made available to the user locally.
 Handover
    The process by which an active MN (in the Active State, see
    section 4.6) changes its point of attachment to the network, or
    when such a change is attempted.  The access network may provide
    features to minimize the interruption to sessions in progress.
    Also called handoff.
    There are different types of handover classified according to
    different aspects involved in the handover.  Some of this
    terminology follows the description in [4].

Manner & Kojo Informational [Page 15] RFC 3753 Mobility Related Terminology June 2004

4.1. Scope of Handover

 Layer 2 handover
    A handover where the MN changes APs (or some other aspect of the
    radio channel) connected to the same AR's interface.  This type of
    handover is transparent to the routing at the IP layer (or it
    appears simply as a link layer reconfiguration without any
    mobility implications).
 Intra-AR handover
    A handover which changes the AR's network interface to the mobile.
    That is, the Serving AR remains the same but routing changes
    internal to the AR take place.
 Intra-AN handover
    A handover where the MN changes ARs inside the same AN.  Such a
    handover is not necessarily visible outside the AN.  In case the
    ANG serving the MN changes, this handover is seen outside the AN
    due to a change in the routing paths.  Note that the ANG may
    change for only some of the MN's data flows.
 Inter-AN handover
    A handover where the MN moves to a new AN.  This requires support
    for macro mobility.  Note that this would have to involve the
    assignment of a new IP access address (e.g., a new care-of
    address) to the MN.
 Intra-technology handover
    A handover between equipment of the same technology.
 Inter-technology handover
    A handover between equipment of different technologies.
 Horizontal handover
    This involves MNs moving between access points of the same type
    (in terms of coverage, data rate and mobility), such as, UMTS to
    UMTS, or WLAN to WLAN.

Manner & Kojo Informational [Page 16] RFC 3753 Mobility Related Terminology June 2004

 Vertical handover
    This involves MNs moving between access points of different type,
    such as, UMTS to WLAN.
 Note that the difference between a horizontal and vertical handover
 is vague.  For example, a handover from an AP with 802.11b WLAN link
 to an AP with 802.11g WLAN link may be considered as either a
 vertical or a horizontal handover, depending on an individual's point
 of view.
 Note also that the IP layer sees network interfaces and IP addresses,
 rather than specific technologies used by those interfaces.  Thus,
 horizontal and vertical handovers may or may not be noticed at the IP
 layer.  Usually a handover can be noticed if the IP address assigned
 to the interface changes, the network interface itself changes (which
 can also change the IP address), or there is a link outage, for
 example, when the mobile node moves out of coverage for a while.  For
 example, in a GPRS network a horizontal handover happens usually
 unnoticed by the IP layer.  Similarly, a WLAN horizontal handover may
 be noticed if the IP address of the interface changes.  On the other
 hand, vertical handovers often change the network interface and are,
 therefore, noticed on the IP layer.  Still, some specific network
 cards may be able to switch between access technologies (e.g., GPRS
 to UMTS) without changing the network interface.  Moreover, either of
 the two handovers may or may not result in changing the AR.  For
 example, an AR could control WLAN and Bluetooth access points, and
 the mobile node could do horizontal and vertical handovers under the
 same AR without changing its IP address or even the network
 interface.

4.2. Handover Control

 A handover must be one of the following two types (a):
    Mobile-initiated handover
       The MN is the one that makes the initial decision to initiate
       the handover.
    Network-initiated handover
       The network makes the initial decision to initiate the
       handover.

Manner & Kojo Informational [Page 17] RFC 3753 Mobility Related Terminology June 2004

 A handover is also one of the following two types (b):
    Mobile-controlled handover
       The MN has the primary control over the handover process.
    Network-controlled handover
       The network has the primary control over the handover process.
 A handover decision usually involves some sort of measurements about
 when and where to handover to.  Therefore, a handover is also either
 of these three types (c):
    Mobile-assisted handover
       Information and measurement from the MN are used by the AR to
       decide on the execution of a handover.
    Network-assisted handover
       A handover where the AN collects information that can be used
       by the MN in a handover decision.
    Unassisted handover
       A handover where no assistance is provided by the MN or the AR
       to each other.
 Note that it is possible that the MN and the AR both do measurements
 and decide on the handover.
 A handover is also one of the following two types (d):
    Push handover
       A handover either initiated by the PAR, or where the MN
       initiates a handover via the PAR.
    Pull handover
       A handover either initiated by the NAR, or where the MN
       initiates a handover via the NAR.

Manner & Kojo Informational [Page 18] RFC 3753 Mobility Related Terminology June 2004

 The handover is also either proactive or reactive (e):
    Planned handover
       A proactive (expected) handover where some signaling can be
       done in advance of the MN getting connected to the new AR,
       e.g., building a temporary tunnel from the previous AR to the
       new AR.
    Unplanned handover
       A reactive (unexpected) handover where no signaling is done in
       advance of the MN's move from the previous AR to the new AR.
 The five handover types (a-e) are mostly independent, and every
 handover should be classifiable according to each of these types.

4.3. Simultaneous connectivity to Access Routers

 Make-before-break (MBB)
    During a MBB handover the MN makes the new connection before the
    old one is broken.  Thus, the MN can communicate simultaneously
    with the old and new AR during the handover.  This should not be
    confused with "soft handover" which relies on macro diversity,
    described in Section 4.5.
 Break-before-make (BBM)
    During a BBM handover the MN breaks the old connection before the
    new connection is made.  Thus, the MN cannot communicate
    simultaneously with the old and the new AR.

4.4. Performance and Functional Aspects

 Handover latency
    Handover latency is the difference between the time a MN is last
    able to send and/or receive an IP packet by way of the PAR, and
    the time the MN is able to send and/or receive an IP packet
    through the NAR.  Adapted from [4].
 Smooth handover
    A handover that aims primarily to minimize packet loss, with no
    explicit concern for additional delays in packet forwarding.

Manner & Kojo Informational [Page 19] RFC 3753 Mobility Related Terminology June 2004

 Fast handover
    A handover that aims primarily to minimize handover latency, with
    no explicit interest in packet loss.
 Seamless handover
    A handover in which there is no change in service capability,
    security, or quality.  In practice, some degradation in service is
    to be expected.  The definition of a seamless handover in the
    practical case should be that other protocols, applications, or
    end users do not detect any change in service capability, security
    or quality, which would have a bearing on their (normal)
    operation.  As a consequence, what would be a seamless handover
    for one less demanding application might not be seamless for
    another more demanding application.  See [7] for more discussion
    on the topic.
 Throughput
    The amount of data from a source to a destination processed by the
    protocol for which throughput is to be measured, for instance, IP,
    TCP, or the MAC protocol.  The throughput differs between protocol
    layers.
 Goodput
    The total bandwidth used, less the volume of control messages,
    protocol overhead from the data packets, and packets dropped due
    to CRC errors.
 Pathloss
    A reduction in signal strength caused by traversing the physical
    medium constituting the link.
 Hidden-terminal problem
    The problem whereby a transmitting node can fail in its attempt to
    transmit data because of destructive interference which is only
    detectable at the receiving node, not the transmitting node.
 Exposed terminal problem
    The problem whereby a transmitting node A prevents another node B
    from transmitting, although node B could have safely transmitted
    to anyone else but the transmitting node A.

Manner & Kojo Informational [Page 20] RFC 3753 Mobility Related Terminology June 2004

4.5. Micro Diversity, Macro Diversity, and IP Diversity

 Certain air interfaces (e.g., the Universal Mobile Telephone System
 (UMTS) Terrestrial Radio Access Network (UTRAN) running in Frequency
 Division Duplex (FDD) mode)  require or at least support macro
 diversity combining.  Essentially, this refers to the fact that a
 single MN is able to send and receive over two independent radio
 channels ('diversity branches') at the same time; the information
 received over different branches is compared and that from the better
 branch passed to the upper layers.  This can be used both to improve
 overall performance, and to provide a seamless type of handover at
 layer 2, since a new branch can be added before the old is deleted.
 See also [6].
 It is necessary to differentiate between combining/diversity that
 occurs at the physical and radio link layers, where the relevant unit
 of data is the radio frame, and that which occurs at layer 3, the
 network layer, where what is considered is the IP packet itself.
 In the following definitions micro- and macro diversity refer to
 protocol layers below the network layer, and IP diversity refers to
 the network layer.
 Micro diversity
    For example, two antennas on the same transmitter send the same
    signal to a receiver over a slightly different path to overcome
    fading.
 Macro diversity
    Duplicating or combining actions taking place over multiple APs,
    possibly attached to different ARs.  This may require support from
    the network layer to move the radio frames between the base
    stations and a central combining point.
 IP diversity
    Refers to the process of duplicating IP packets and sending them
    to the receiver through more than one point of attachment.  This
    is semantically allowed by IP because it does not guarantee packet
    uniqueness, and higher level protocols are assumed to eliminate
    duplicates whenever that is important for the application.

Manner & Kojo Informational [Page 21] RFC 3753 Mobility Related Terminology June 2004

4.6. Paging, and Mobile Node States and Modes

 Mobile systems may employ the use of MN states in order to operate
 more efficiently without degrading the performance of the system.
 The term 'mode' is also common and means the same as 'state'.
 A MN is always in one of the following three states:
 Active state
    When the AN knows the MN's SAR and the MN can send and receive IP
    packets.  The access link may not be active, but the radio layer
    is able to establish one without assistance from the network
    layer.  The MN has an IP address assigned.
 Dormant state
    A state in which the mobile restricts its ability to receive
    normal IP traffic by reducing its monitoring of radio channels.
    The AN knows the MN's Paging Area, but the MN has no SAR and so
    packets cannot be delivered to the MN without the AN initiating
    paging.  Often also called Idle state.
    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 paging messages to the mobile during
       listening periods.
 Inactive state
    the MN is in neither the Active nor Dormant State.  The MN is no
    longer listening for any packets, not even periodically, and not
    sending packets.  The MN may be in a powered off state, it may
    have shut down all interfaces to drastically conserve power, or it
    may be out of range of a radio access point.  The MN does not
    necessarily have an IP access address from the AN.
 Note: in fact, as well as the MN being in one of these three states,
 the AN also stores which state it believes the MN is in.  Normally
 these are consistent; the definitions above assume so.
 Here are some additional definitions for paging, taking into account
 the above state definitions.

Manner & Kojo Informational [Page 22] RFC 3753 Mobility Related Terminology June 2004

 Paging
    A procedure initiated by the Access Network to move a Dormant MN
    into the Active State.  As a result of paging, the MN establishes
    a SAR and the IP routes are set up.
 Location updating
    A procedure initiated by the MN, by which it informs the AN that
    it has moved into a new paging area.
 Paging area
    A part of the Access Network, typically containing a number of
    ARs/APs, which corresponds to some geographical area.  The AN
    keeps and updates a list of all the Dormant MNs present in the
    area.  If the MN is within the radio coverage of the area it will
    be able to receive paging messages sent within that Paging Area.
 Paging area registrations
    Signaling from a dormant mode mobile node to the network, by which
    it establishes its presence in a new paging area.  Paging Area
    Registrations thus enable the network to maintain a rough idea of
    where the mobile is located.
 Paging channel
    A radio channel dedicated to signaling dormant mode mobiles for
    paging purposes.  By current practice, the paging channel carries
    only control traffic necessary for the radio link, 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.

Manner & Kojo Informational [Page 23] RFC 3753 Mobility Related Terminology June 2004

4.7. Context Transfer

 Context
    The information on the current state of a routing-related service
    required to re-establish the routing-related service on a new
    subnet without having to perform the entire protocol exchange with
    the MN from scratch.
 Feature context
    The collection of information representing the context for a given
    feature.  The full context associated with a MN is the collection
    of one or more feature contexts.
 Context transfer
    The movement of context from one router or other network entity to
    another as a means of re-establishing routing-related services on
    a new subnet or collection of subnets.
 Routing-related service
    A modification to the default routing treatment of packets to and
    from the MN.  Initially establishing routing-related services
    usually requires a protocol exchange with the MN.  An example of a
    routing-related service is header compression.  The service may
    also be indirectly related to routing, for example, security.
    Security may not affect the forwarding decision of all
    intermediate routers, but a packet may be dropped if it fails a
    security check (can't be encrypted, authentication failed, etc.).
    Dropping the packet is basically a routing decision.

4.8. Candidate Access Router Discovery

 Capability of an AR
    A characteristic of the service offered by an AR that may be of
    interest to an MN when the AR is being considered as a handoff
    candidate.
 Candidate AR (CAR)
    An AR to which MN has a choice of performing IP-level handoff.
    This means that MN has the right radio interface to connect to an
    AP that is served by this AR, as well as the coverage of this AR
    overlaps with that of the AR to which MN is currently attached.

Manner & Kojo Informational [Page 24] RFC 3753 Mobility Related Terminology June 2004

 Target AR (TAR)
    An AR with which the procedures for the MN's IP-level handoff are
    initiated.  TAR is selected after running a TAR Selection
    Algorithm that takes into account the capabilities of CARs,
    preferences of MN and any local policies.

4.9. Types of Mobility

 We can differentiate between host and network mobility, and various
 types of network mobility.  Terminology related more to applications
 such as the Session Initiation Protocol, such as personal mobility,
 is out of scope for this document.
    Host mobility support
       Refers to the function of allowing a mobile node to change its
       point of attachment to the network, without interrupting IP
       packet delivery to/from that node.  There may be different sub-
       functions depending on what the current level of service is
       being provided; in particular, support for host mobility
       usually implies active and dormant modes of operation,
       depending on whether the node has any current sessions or not.
       Access Network procedures are required to keep track of the
       current point of attachment of all the MNs or establish it at
       will.  Accurate location and routing procedures are required in
       order to maintain the integrity of the communication.  Host
       mobility is often called 'terminal mobility'.
    Network mobility support
       Refers to the function of allowing an entire network to change
       its point of attachment to the Internet, and, thus, its
       reachability in the topology, without interrupting IP packet
       delivery to/from that mobile network.
 Two subcategories of mobility can be identified within both host
 mobility and network mobility:
    Global mobility
       Same as Macro mobility.
    Local mobility
       Same as Micro mobility.

Manner & Kojo Informational [Page 25] RFC 3753 Mobility Related Terminology June 2004

    Macro mobility
       Mobility over a large area.  This includes mobility support and
       associated address registration procedures that are needed when
       a MN moves between IP domains.  Inter-AN handovers typically
       involve macro-mobility protocols.  Mobile-IP can be seen as a
       means to provide macro mobility.
    Micro mobility
       Mobility over a small area.  Usually this means mobility within
       an IP domain with an emphasis on support for active mode using
       handover, although it may include idle mode procedures also.
       Micro-mobility protocols exploit the locality of movement by
       confining movement related changes and signaling to the access
       network.
    Local mobility management
       Local mobility management (LMM) is a generic term for protocols
       dealing with IP mobility management confined within the access
       network.  LMM messages are not routed outside the access
       network, although a handover may trigger Mobile IP messages to
       be sent to correspondent nodes and home agents.

5. Specific Terminology for Mobile Ad-Hoc Networking

 Cluster
    A group of nodes located within close physical proximity,
    typically all within range of one another, which can be grouped
    together for the purpose of limiting the production and
    propagation of routing information.
 Cluster head
    A cluster head is a node (often elected in the cluster formation
    process) that has complete knowledge about group membership and
    link state information in the cluster.  Each cluster should have
    one and only one cluster head.
 Cluster member
    All nodes within a cluster except the cluster head are called
    members of that cluster.

Manner & Kojo Informational [Page 26] RFC 3753 Mobility Related Terminology June 2004

 Convergence
    The process of approaching a state of equilibrium in which all
    nodes in the network agree on a consistent collection of state
    about the topology of the network, and in which no further control
    messages are needed to establish the consistency of the network
    topology.
 Convergence time
    The time which is required for a network to reach convergence
    after an event (typically, the movement of a mobile node) which
    changes the network topology.
 Laydown
    The relative physical location of the nodes within the ad hoc
    network.
 Pathloss matrix
    A matrix of coefficients describing the pathloss between any two
    nodes in an ad hoc network.  When the links are asymmetric, the
    matrix is also asymmetric.
 Scenario
    The tuple <laydown, pathloss matrix, mobility factor, traffic>
    characterizing a class of ad hoc networks.

6. Security-related Terminology

 This section includes terminology commonly used around mobile and
 wireless networking.  Only a mobility-related subset of the entire
 security terminology is presented.
    Authorization-enabling extension
       An authentication which makes a (registration) message
       acceptable to the ultimate recipient of the registration
       message.  An authorization-enabling extension must contain an
       SPI (see below) [10].
    Mobility security association
       A collection of security contexts, between a pair of nodes,
       which may be applied to mobility-related protocol messages
       exchanged between them.  In Mobile IP, each context indicates

Manner & Kojo Informational [Page 27] RFC 3753 Mobility Related Terminology June 2004

       an authentication algorithm and mode, a secret (a shared key,
       or appropriate public/private key pair), and a style of replay
       protection in use.  Mobility security associations may be
       stored separately from the node's IPsec Security Policy
       Database (SPD) [10].
    Registration key
       A key used in the Mobility Security Association between a
       mobile node and a foreign agent.  A registration key is
       typically only used once or a very few times, and only for the
       purposes of verifying a small volume of Authentication data
       [12].
    Security context
       A security context between two nodes defines the manner in
       which two nodes choose to mutually authenticate each other, and
       indicates an authentication algorithm and mode.
    Security Parameter Index (SPI)
       An index identifying a security context between a pair of
       routers among the contexts available in the mobility security
       association.
 The Mobile IPv6 specification includes more security terminology
 related to MIPv6 bindings [9].  Terminology about the MIP
 challenge/response mechanism can be found in [11].

7. Security Considerations

 This document presents only terminology.  There are no security
 issues in this document.

8. Contributors

 This document was initially based on the work of Tapio Suihko, Phil
 Eardley, Dave Wisely, Robert Hancock, Nikos Georganopoulos, Markku
 Kojo, and Jukka Manner.
 Charles Perkins has provided input terminology related to ad-hoc
 networks.
 Thierry Ernst has provided the terminology for discussing mobile
 networks.

Manner & Kojo Informational [Page 28] RFC 3753 Mobility Related Terminology June 2004

 Henrik Levkowetz did a final check of the definitions in revision -05
 and suggested a number of changes.

9. Acknowledgments

 This work has been partially performed in the framework of the IST
 project IST-2000-28584 MIND, which is partly funded by the European
 Union.  Some of the authors would like to acknowledge the help of
 their colleagues in preparing this document.
 Randy Presuhn did a very thorough and helpful review of the -02
 version of the terminology.
 Some definitions of terminology have been adapted from [1], [2], [3],
 [4], [7], [8], [9] and [10].

10. Informative References

 [1]  Blair, D., Tweedly, A., Thomas, M., Trostle, J. and M. Ramalho,
      "Realtime Mobile IPv6 Framework", Work in Progress.
 [2]  Calhoun, P., Montenegro, G. and C. Perkins, "Mobile IP
      Regionalized Tunnel Management", Work in Progress.
 [3]  Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6)
      Specification", RFC 2460, December 1998.
 [4]   Koodli, R., Ed., "Fast Handovers for Mobile IPv6", Work in
      Progress.
 [5]  Yavatkar, R., Pendarakis, D. and R. Guerin, "A Framework for
      Policy-based Admission Control", RFC 2753, January 2000.
 [6]  Kempf, J., McCann, P. and P. Roberts, "IP Mobility and the CDMA
      Radio Access Network:  Applicability Statement for Soft
      Handoff", Work in Progress.
 [7]  Kempf, J., Ed., "Problem Description:  Reasons For Performing
      Context Transfers Between Nodes in an IP Access Network", RFC
      3374, September 2002.
 [8]  Trossen, D., Krishnamurthi, G., Chaskar, H. and J. Kempf,
      "Issues in candidate access router discovery for seamless IP-
      level handoffs", Work in Progress.
 [9]  Johnson, D., Perkins, C. and J. Arkko, "Mobility Support in
      IPv6", RFC 3775, June 2004.

Manner & Kojo Informational [Page 29] RFC 3753 Mobility Related Terminology June 2004

 [10] Perkins, C., Ed., "IP Mobility Support for IPv4", RFC 3344,
      August 2002.
 [11] Perkins, C., Calhoun, P. and J. Bharatia, "Mobile IPv4
      Challenge/Response Extensions (revised)", Work in Progress.
 [12] Perkins, C. and P. Calhoun, "AAA Registration Keys for Mobile
      IP", Work in Progress.
 [13] Ernst, T. and H. Lach, "Network Mobility Support Terminology",
      Work in Progress.
 [14] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.

Manner & Kojo Informational [Page 30] RFC 3753 Mobility Related Terminology June 2004

11. Appendix A - Index of Terms

 AD ............................................................. 14
 AL ............................................................. 13
 AN ............................................................. 14
 ANG ............................................................ 14
 ANR ............................................................ 13
 AP ............................................................. 13
 AR ............................................................. 14
 Access Link .................................................... 13
 Access Network ................................................. 14
 Access Network Gateway ......................................... 14
 Access Network Router .......................................... 13
 Access Point ................................................... 13
 Access Router .................................................. 14
 Active state ................................................... 22
 Administrative Domain .......................................... 14
 Asymmetric link ................................................. 5
 Authorization-enabling extension ............................... 27
 BBM ............................................................ 19
 BU .............................................................. 3
 Bandwidth ....................................................... 2
 Bandwidth utilization ........................................... 2
 Beacon .......................................................... 3
 Binding Update .................................................. 3
 Break-before-make .............................................. 19
 CAR ............................................................ 15
 CAR ............................................................ 24
 Candidate AR ................................................... 24
 Candidate Access Router ........................................ 15
 Capability of an AR ............................................ 24
 Care-of-Address ................................................. 3
 Channel ......................................................... 3
 Channel access protocol ......................................... 3
 Channel capacity ................................................ 3
 Cluster ........................................................ 26
 Cluster head ................................................... 26
 Cluster member ................................................. 26
 CoA ............................................................. 3
 Context ........................................................ 24
 Context transfer ............................................... 24
 Control message ................................................. 4
 Convergence .................................................... 27
 Convergence time ............................................... 27
 Distance vector ................................................. 4
 Dormant state .................................................. 22
 Egress interface ............................................... 13
 Exposed terminal problem ....................................... 20

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 FN ............................................................. 12
 Fairness ........................................................ 4
 Fast handover .................................................. 20
 Feature context ................................................ 24
 Fixed Node ..................................................... 12
 Flooding ........................................................ 4
 Foreign subnet prefix ........................................... 4
 Forwarding node ................................................. 4
 Global mobility ................................................ 25
 Goodput ........................................................ 20
 HA .............................................................. 5
 Handoff ........................................................ 15
 Handover ....................................................... 15
 Handover latency ............................................... 19
 Hidden-terminal problem ........................................ 20
 HoA ............................................................. 4
 Home Address .................................................... 4
 Home Agent ...................................................... 5
 Home subnet prefix .............................................. 5
 Horizontal Handover ............................................ 16
 Host mobility support .......................................... 25
 IP access address ............................................... 5
 IP diversity ................................................... 21
 Inactive state ................................................. 22
 Ingress interface .............................................. 12
 Inter-AN handover .............................................. 16
 Inter-technology handover ...................................... 16
 Interface ....................................................... 5
 Intra-AN handover .............................................. 16
 Intra-AR handover .............................................. 16
 Intra-technology handover ...................................... 16
 L2 Trigger ...................................................... 6
 Laydown ........................................................ 27
 Layer 2 handover ............................................... 16
 Link ............................................................ 5
 Link establishment .............................................. 6
 Link state ...................................................... 6
 Link-layer trigger .............................................. 6
 Link-level acknowledgment ....................................... 6
 Local broadcast ................................................. 6
 Local mobility ................................................. 25
 Local mobility management ...................................... 26
 Location updating .............................................. 23
 Loop-free ....................................................... 6
 MAC ............................................................. 7
 MBB ............................................................ 19
 MH ............................................................. 12
 MN ............................................................. 12

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 MNN ............................................................ 13
 MPR ............................................................. 7
 MR ............................................................. 12
 Macro diversity ................................................ 21
 Macro mobility ................................................. 26
 Make-before-break .............................................. 19
 Medium Access Protocol .......................................... 7
 Micro diversity ................................................ 21
 Micro mobility ................................................. 26
 Mobile Host .................................................... 12
 Mobile Network Node ............................................ 13
 Mobile Node .................................................... 12
 Mobile Router .................................................. 12
 Mobile network ................................................. 12
 Mobile network prefix ........................................... 7
 Mobile-assisted handover ....................................... 18
 Mobile-controlled handover ..................................... 18
 Mobile-initiated handover ...................................... 17
 Mobility factor ................................................. 7
 Mobility security association .................................. 27
 Multipoint relay ................................................ 7
 NAR ............................................................ 14
 Neighbor ........................................................ 7
 Neighborhood .................................................... 7
 Network mobility support ....................................... 25
 Network-assisted handover ...................................... 18
 Network-controlled handover .................................... 18
 Network-initiated handover ..................................... 17
 New Access Router .............................................. 14
 Next hop ........................................................ 7
 PAR ............................................................ 15
 Paging ......................................................... 23
 Paging area .................................................... 23
 Paging area registrations ...................................... 23
 Paging channel ................................................. 23
 Pathloss ....................................................... 20
 Pathloss matrix ................................................ 27
 Payload ......................................................... 8
 Planned handover ............................................... 19
 Prefix .......................................................... 8
 Previous Access Router ......................................... 15
 Pull handover .................................................. 18
 Push handover .................................................. 18
 Radio Cell ..................................................... 13
 Registration key ............................................... 28
 Roaming ........................................................ 15
 Route activation ................................................ 8
 Route entry ..................................................... 8

Manner & Kojo Informational [Page 33] RFC 3753 Mobility Related Terminology June 2004

 Route establishment ............................................. 8
 Routing table ................................................... 8
 Routing proxy ................................................... 8
 Routing-related service ........................................ 24
 SAR ............................................................ 14
 SPI ............................................................ 28
 Scenario ....................................................... 27
 Seamless handover .............................................. 19
 Security Parameter Index ....................................... 28
 Security context ............................................... 28
 Serving Access Router .......................................... 14
 Shannon's Law ................................................... 9
 Signal strength ................................................. 9
 Smooth handover ................................................ 19
 Source route .................................................... 9
 Spatial re-use .................................................. 9
 Subnet .......................................................... 9
 System-wide broadcast ........................................... 9
 TAR ............................................................ 25
 Target AR ...................................................... 25
 Throughput ..................................................... 20
 Time-slotted dormant mode ...................................... 22
 Topology ........................................................ 9
 Traffic channel ................................................ 23
 Triggered update ................................................10
 Unassisted handover ............................................ 18
 Unplanned handover ............................................. 19
 Vertical handover .............................................. 17

Manner & Kojo Informational [Page 34] RFC 3753 Mobility Related Terminology June 2004

12. Authors' Addresses

 Jukka Manner
 Department of Computer Science
 University of Helsinki
 P.O. Box 26 (Teollisuuskatu 23)
 FIN-00014 HELSINKI
 Finland
 Phone: +358-9-191-44210
 Fax:   +358-9-191-44441
 EMail: jmanner@cs.helsinki.fi
 Markku Kojo
 Department of Computer Science
 University of Helsinki
 P.O. Box 26 (Teollisuuskatu 23)
 FIN-00014 HELSINKI
 Finland
 Phone: +358-9-191-44179
 Fax:   +358-9-191-44441
 EMail: kojo@cs.helsinki.fi

Manner & Kojo Informational [Page 35] RFC 3753 Mobility Related Terminology June 2004

13. Full Copyright Statement

 Copyright (C) The Internet Society (2004).  This document is subject
 to the rights, licenses and restrictions contained in BCP 78, and
 except as set forth therein, the authors retain all their rights.
 This document and the information contained herein are provided on an
 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
 REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE
 INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

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 The IETF takes no position regarding the validity or scope of any
 Intellectual Property Rights or other rights that might be claimed
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 under such rights might or might not be available; nor does it
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 Copies of IPR disclosures made to the IETF Secretariat and any
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Acknowledgement

 Funding for the RFC Editor function is currently provided by the
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