draft-ietf-seamoby-mobility-terminology-05.txt   draft-ietf-seamoby-mobility-terminology-06.txt 
Internet Engineering Task Force J. Manner (ed.) INTERNET-DRAFT J. Manner, Editor
Internet-Draft M. Kojo (ed.) draft-ietf-seamoby-mobility-terminology-06.txt M. Kojo, Editor
Expires: May, 2004 University of Helsinki Category: Informational February, 2004
November, 2003 Expires: August, 2004
Mobility Related Terminology Mobility Related Terminology
<draft-ietf-seamoby-mobility-terminology-05.txt>
Status of this Memo Status of this Memo
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all provisions of Section 10 of RFC2026. Internet-Drafts are working all provisions of Section 10 of RFC2026.
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Abstract Abstract
There is a need for common definitions of terminology in the work to There is a need for common definitions of terminology in the work to
be done around IP mobility. This memo defines terms for mobility be done around IP mobility. This document defines terms for mobility
related terminology. It is intended as a living document for use by related terminology. The document originated out of work done in the
the Seamoby Working Group in Seamoby drafts and in WG discussions, Seamoby Working Group but has broader applicability for terminology
but not limited in scope to the terms needed by the Seamoby Working used in IETF-wide discourse on technology for mobility and IP
Group. Other working groups dealing with mobility may take advantage networks. Other working groups dealing with mobility may want to take
of this terminology. advantage of this terminology.
Table of Contents Table of Contents
1 Introduction ................................................. 2 1 Introduction ................................................. 2
2 General Terms ................................................ 3 2 General Terms ................................................ 3
3 Mobile Access Networks and Mobile Networks ................... 8 3 Mobile Access Networks and Mobile Networks ................... 9
4 Handover Terminology ......................................... 13 4 Handover Terminology ......................................... 13
4.1 Scope of Handover .......................................... 14 4.1 Scope of Handover .......................................... 14
4.2 Handover Control ........................................... 15 4.2 Handover Control ........................................... 15
4.3 Simultaneous connectivity to Access Routers ................ 17 4.3 Simultaneous connectivity to Access Routers ................ 17
4.4 Performance and Functional Aspects ......................... 17 4.4 Performance and Functional Aspects ......................... 17
4.5 Micro Diversity, Macro Diversity, and IP Diversity ......... 18 4.5 Micro Diversity, Macro Diversity, and IP Diversity ......... 18
4.6 Paging, and Mobile Node States and Modes ................... 19 4.6 Paging, and Mobile Node States and Modes ................... 19
4.7 Context Transfer ........................................... 21 4.7 Context Transfer ........................................... 21
4.8 Candidate Access Router Discovery .......................... 21 4.8 Candidate Access Router Discovery .......................... 21
4.9 Types of Mobility .......................................... 22 4.9 Types of Mobility .......................................... 22
5 Specific Terminology for Mobile Ad-Hoc Networking ............ 23 5 Specific Terminology for Mobile Ad-Hoc Networking ............ 23
6 Security-related Terminology ................................. 24 6 Security-related Terminology ................................. 24
7 Security Considerations ...................................... 25 7 Security Considerations ...................................... 25
8 Contributors ................................................. 25 8 Contributors ................................................. 25
9 Change log ................................................... 26 9 Acknowledgments .............................................. 25
10 Acknowledgement ............................................. 26 10 Informative References ...................................... 26
11 Informative References ...................................... 27 11 Authors' Addresses .......................................... 27
12 Authors' Addresses .......................................... 28 12 Appendix A - Index of Terms ................................. 29
13 Appendix A - Examples ....................................... 30
14 Appendix B - Index of Terms ................................. 33
1. Introduction 1. Introduction
This document presents terminology to be used for documents and This document presents terminology to be used for documents and
discussions within the Seamoby Working Group. Other mobility related discussions within the Seamoby Working Group. Other mobility related
working groups could take advantage of this terminology, in order to working groups could take advantage of this terminology, in order to
create a common terminology for the area of mobility in IP networks. create a common terminology for the area of mobility in IP networks.
These groups would include MIP, MANET, ROHC and NEMO. These groups would include MIP, MANET, ROHC and NEMO.
Some terms and their definitions that are not directly related to the Some terms and their definitions that are not directly related to the
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The terminology in this draft is divided into several sections. The terminology in this draft is divided into several sections.
First, there is a list of terms for general use and mobile access First, there is a list of terms for general use and mobile access
networks followed by terms related to handovers, and finally some networks followed by terms related to handovers, and finally some
terms used within the MANET and NEMO working group. terms used within the MANET and NEMO working group.
2. General Terms 2. General Terms
Bandwidth Bandwidth
The total capacity of a link to carry information (typically The total width of the frequency band available to or used by a
bits) per unit time. communications channel. Usually measured in Hertz (Hz). The
bandwidth of a channel limits the available channel capacity.
Bandwidth utilization Bandwidth utilization
The actual rate of information transfer achieved over a link, The actual rate of information transfer achieved over a link,
expressed as a percent of the available bandwidth on that link. expressed as a percentage of the theoretical maximum channel
capacity on that link, according to Shannon's Law.
Beacon Beacon
A control message broadcast by a node (especially, a base A control message broadcast by a node (especially, a base
station) informing all the other nodes in its neighborhood of the station) informing all the other nodes in its neighborhood of the
continuing presence of the broadcasting node, possibly along with continuing presence of the broadcasting node, possibly along with
additional status or configuration information. additional status or configuration information.
Binding Update (BU) Binding Update (BU)
A message indicating a mobile node's current mobility binding, A message indicating a mobile node's current mobility binding,
and in particular its care-of address. and in particular its care-of address.
Care-of-Address (CoA) Care-of-Address (CoA)
An IP address associated with a mobile node while visiting a An IP address associated with a mobile node while visiting a
foreign link; the subnet prefix of this IP address is a foreign foreign link; the subnet prefix of this IP address is a foreign
subnet prefix. Among the multiple care-of addresses that a subnet prefix. A packet addressed to the mobile node which
mobile node may have at any given time (e.g., with different arrives at the mobile node's home network when the mobile node is
subnet prefixes), the one registered with the mobile node's home away from home and has registered a Care-of Address will be
agent is called its "primary" care-of address [11]. forwarded to that address by the Home Agent in the home network.
Channel Channel
A subdivision of the physical medium allowing possibly shared A subdivision of the physical medium allowing possibly shared
independent uses of the medium. Channels may be made available independent uses of the medium. Channels may be made available
by subdividing the medium into distinct time slots, or distinct by subdividing the medium into distinct time slots, or distinct
spectral bands, or decorrelated coding sequences. spectral bands, or decorrelated coding sequences.
Channel access protocol Channel access protocol
A protocol for mediating access to, and possibly allocation of, A protocol for mediating access to, and possibly allocation of,
the various channels available within the physical communications the various channels available within the physical communications
medium. Nodes participating in the channel access protocol agree medium. Nodes participating in the channel access protocol agree
to communicate only when they have uncontested access to one of to communicate only when they have uncontested access to one of
the channels, so that there will be no interference. 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.
Control message Control message
Information passed between two or more network nodes for Information passed between two or more network nodes for
maintaining protocol state, which may be unrelated to any maintaining protocol state, which may be unrelated to any
specific application. specific application.
Distance vector Distance vector
A style of routing protocol in which, for each desired A characteristic of some routing protocols in which, for each
destination, a node maintains information about the distance to desired destination, a node maintains information about the
that destination, and a vector (next hop) towards that distance to that destination, and a vector (next hop) towards
destination. that destination.
Fairness Fairness
A property of channel access protocols whereby a medium is made A property of channel access protocols whereby a medium is made
fairly available to all eligible nodes on the link. Fairness fairly available to all eligible nodes on the link. Fairness
does not strictly imply equality, especially in cases where nodes does not strictly imply equality, especially in cases where nodes
are given link access according to unequal priority or are given link access according to unequal priority or
classification. classification.
Flooding Flooding
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one of its neighbors to another. one of its neighbors to another.
Home Address (HoA) Home Address (HoA)
An IP address assigned to a mobile node, used as the permanent An IP address assigned to a mobile node, used as the permanent
address of the mobile node. This address is within the mobile address of the mobile node. This address is within the mobile
node's home link. Standard IP routing mechanisms will deliver node's home link. Standard IP routing mechanisms will deliver
packets destined for a mobile node's home address to its home packets destined for a mobile node's home address to its home
link [11]. link [11].
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 Home subnet prefix
A bit string that consists of some number of initial bits of an A bit string that consists of some number of initial bits of an
IP address which identifies a node's home link within the IP address which identifies a node's home link within the
Internet topology (i.e. the IP subnet prefix corresponding to the Internet topology (i.e. the IP subnet prefix corresponding to the
mobile node's home address, as defined in [11]). mobile node's home address, as defined in [11]).
Interface Interface
A node's attachment to a link. A node's point of attachment to a link.
IP access address IP access address
An IP address (often dynamically allocated) which a node uses to An IP address (often dynamically allocated) which a node uses to
designate its current point of attachment to the local network. designate its current point of attachment to the local network.
The IP access address is typically to be distinguished from the The IP access address is typically to be distinguished from the
mobile node's home address; in fact, while visiting a foreign mobile node's home address; in fact, while visiting a foreign
network the former may be considered unsuitable for use as an network the former may be considered unsuitable for use as an
end-point address by any but the most short-lived applications. end-point address by any but the most short-lived applications.
Instead, the IP access address is typically used as the care-of Instead, the IP access address is typically used as the care-of
address of the node. address of the node.
Link Link
A communication facility or physical medium that can sustain data A communication facility or physical medium that can sustain data
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network the former may be considered unsuitable for use as an network the former may be considered unsuitable for use as an
end-point address by any but the most short-lived applications. end-point address by any but the most short-lived applications.
Instead, the IP access address is typically used as the care-of Instead, the IP access address is typically used as the care-of
address of the node. address of the node.
Link Link
A communication facility or physical medium that can sustain data A communication facility or physical medium that can sustain data
communications between multiple network nodes, such as an communications between multiple network nodes, such as an
Ethernet (simple or bridged). A link is the layer immediately Ethernet (simple or bridged). A link is the layer immediately
below IP. In IP networks, a link usually connects two IP-based below IP. In a layered network stack model, the Link Layer (Layer
nodes, for example, a mobile node and an access router (see below 2) is normally below the Network (IP) Layer (Layer 3), and above
the term "access link"). the Physical Layer (Layer 1).
Asymmetric link Asymmetric link
A link with transmission characteristics which are different A link with transmission characteristics which are different
depending upon the relative position or design characteristics of depending upon the relative position or design characteristics of
the transmitter and the receiver of data on the link. For the transmitter and the receiver of data on the link. For
instance, the range of one transmitter may be much higher than instance, the range of one transmitter may be much higher than
the range of another transmitter on the same medium. the range of another transmitter on the same medium.
Link establishment Link establishment
The process of establishing a link between the mobile node and The process of establishing a link between the mobile node and
the local network. This may involve allocating a channel, or the local network. This may involve allocating a channel, or
other local wireless resources, possibly including a minimum other local wireless resources, possibly including a minimum
level of service or bandwidth. level of service or bandwidth.
Link-layer trigger (L2 Trigger) Link-layer trigger (L2 Trigger)
Information from L2 that informs L3 of the detailed events Information from the link layer that informs the network layer of
involved in handover sequencing at L2. L2 triggers are not the detailed events involved in handover sequencing at the link
specific to any particular L2, but rather represent layer. L2 triggers are not specific to any particular link layer,
generalizations of L2 information available from a wide variety but rather represent generalizations of link layer information
of L2 protocols [4]. available from a wide variety of link layer protocols [4].
Link state Link state
A style of routing protocol in which every node within the A characterization of some routing protocols in which every node
network is expected to maintain information about every link within the network is expected to maintain information about
within the network topology. every link within the network topology.
Link-level acknowledgement Link-level acknowledgment
A protocol strategy, typically employed over wireless media, A protocol strategy, typically employed over wireless media,
requiring neighbors to acknowledge receipt of packets (typically requiring neighbors to acknowledge receipt of packets (typically
unicast only) from the transmitter. Such strategies aim to avoid unicast only) from the transmitter. Such strategies aim to avoid
packet loss or delay resulting from lack of, or unwanted packet loss or delay resulting from lack of, or unwanted
characteristics of, higher level protocols. characteristics of, higher level protocols. Link-layer
acknowledgments are often used as part of Automatic Repeat-
Link-layer acknowledgements are often used as part of ARQ Request (ARQ) algorithms for increasing link reliability.
algorithms for increasing link reliability.
Local broadcast Local broadcast
The delivery of data to every node within range of the The delivery of data to every node within range of the
transmitter. transmitter.
Loop-free Loop-free
A property of routing protocols whereby the path taken by a data A property of routing protocols whereby the path taken by a data
packet from source to destination never transits the same packet from source to destination never transits the same
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medium access protocol can communicate only when they have medium access protocol can communicate only when they have
uncontested access to the medium, so that there will be no uncontested access to the medium, so that there will be no
interference. When the physical medium is a radio channel, the interference. When the physical medium is a radio channel, the
MAC is the same as the Channel Access Protocol. MAC is the same as the Channel Access Protocol.
Mobile network prefix Mobile network prefix
A bit string that consists of some number of initial bits of an A bit string that consists of some number of initial bits of an
IP address which identifies the entire mobile network within the IP address which identifies the entire mobile network within the
Internet topology. All nodes in a mobile network necessarily have Internet topology. All nodes in a mobile network necessarily have
an address named after this prefix. an address containing this prefix.
Mobility factor Mobility factor
The relative frequency of node movement, compared to the The relative frequency of node movement, compared to the
frequency of application initiation. frequency of application initiation.
Multipoint relay (MPR) Multipoint relay (MPR)
A node which is selected by its one-hop neighbor to re-transmit A node which is selected by its one-hop neighbor to re-transmit
all broadcast messages that it receives. The message must be new all broadcast messages that it receives. The message must be new
and the time-to-live field of the message must be greater than and the time-to-live field of the message must be greater than
one. Multipoint relaying is a technique to reduce the number of one. Multipoint relaying is a technique to reduce the number of
redundant re-transmissions while diffusing a broadcast message in redundant re-transmissions while diffusing a broadcast message in
the network. the network.
Neighbor Neighbor
A "neighbor" is any other node to which data may be propagated A "neighbor" is any other node to which data may be propagated
directly over the communications medium without relying the directly over the communications medium without relying on the
assistance of any other forwarding node. assistance of any other forwarding node.
Neighborhood Neighborhood
All the nodes which can receive data on the same link from one All the nodes which can receive data on the same link from one
node whenever it transmits data. node whenever it transmits data.
Next hop Next hop
A neighbor which has been selected to forward packets along the A neighbor which has been selected to forward packets along the
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payloads are different between layers: user data is the payload payloads are different between layers: user data is the payload
of TCP, which are the payload of IP, which three are 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 of link layer protocols etc. Thus, it is important to identify
the scope when talking about payloads. the scope when talking about payloads.
Prefix Prefix
A bit string that consists of some number of initial bits of an A bit string that consists of some number of initial bits of an
address. address.
Route table Routing table
The table where forwarding nodes keep information (including next The table where forwarding nodes keep information (including next
hop) for various destinations. hop) for various destinations.
Route entry Route entry
An entry for a specific destination (unicast or multicast) in the An entry for a specific destination (unicast or multicast) in the
route table. routing table.
Route establishment Route establishment
The process of determining a route between a source and a The process of determining a route between a source and a
destination. destination.
Route activation Route activation
The process of putting a route into use after it has been The process of putting a route into use after it has been
determined. determined.
Routing proxy Routing proxy
A node that routes packets by overlays, eg. by tunneling, between A node that routes packets by overlays, e.g.. by tunneling,
communicating partners. The Home Agent and Foreign Agent are between communicating partners. The Home Agent and Foreign Agent
examples of routing proxies, in that they receive packets are examples of routing proxies, in that they receive packets
destined for the mobile node and tunnel them to the current destined for the mobile node and tunnel them to the current
address of the mobile node. address of the mobile node.
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 Signal strength
The detectable power of the signal carrying the data bits, as The detectable power of the signal carrying the data bits, as
seen by the receiver of the signal. seen by the receiver of the signal.
Source route Source route
A source route from node A to node B is an ordered list of IP 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 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 the IP address of the node B. Between A and B, the source route
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System-wide broadcast System-wide broadcast
Same as flooding, but used in contrast to local broadcast. Same as flooding, but used in contrast to local broadcast.
Subnet Subnet
A subnet is a logical group of connected network nodes. In IP A subnet is a logical group of connected network nodes. In IP
networks, nodes in a subnet share a common network mask (in IPV4) networks, nodes in a subnet share a common network mask (in IPV4)
or a network prefix (in IPv6). or a network prefix (in IPv6).
Topology Topology (Network Topology)
A network can be viewed abstractly as a "graph" whose "topology" The interconnection structure of a network: which nodes are
at any point in time is defined by set of "points" connected by directly connected to each other, and through which links they
(possibly directed) "edges." are connected. Some simple topologies have been given names,
such as for instance 'bus topology', 'mesh topology', 'ring
topology', 'star topology' and 'tree topology'.
Triggered update Triggered update
An unsolicited route update transmitted by an router along a path A solicited route update transmitted by a router along a path to
to a destination. a destination.
3. Mobile Access Networks and Mobile Networks 3. Mobile Access Networks and Mobile Networks
In order to support host mobility a set of nodes towards the network 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 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 mobile access network that may or may not be part of the global
Internet. Figure 1 presents two examples of such access network Internet. Figure 1 presents two examples of such access network
topologies. The figure depicts a reference architecture which topologies. The figure depicts a reference architecture which
illustrates an IP network with components defined in this section. illustrates an IP network with components defined in this section.
We intend to define the concept of the Access Network (AN) which may We intend to define the concept of the Access Network (AN) which may
also support enhanced mobility. It is possible that to support also support enhanced mobility. It is possible that to support
routing and QoS for mobile nodes, existing routing protocols (e.g., routing and QoS for mobile nodes, existing routing protocols (e.g.,
OSPF or other standard IGPs) may not be appropriate to maintain Open Shortest Path First (OSPF) [16]) may not be appropriate to
forwarding information for these mobile nodes as they change their maintain forwarding information for these mobile nodes as they change
points of attachment to the Access Network. These new functions are their points of attachment to the Access Network. These new functions
implemented in routers with additional capability. We can distinguish are implemented in routers with additional capabilities. We can
three types of Access Network components: Access Routers (AR) which distinguish three types of Access Network components: Access Routers
handle the last hop to the mobile, typically over a wireless link; (AR) which handle the last hop to the mobile, typically over a
Access Network Gateways (ANG) which form the boundary on the fixed wireless link; Access Network Gateways (ANG) which form the boundary
network side and shield the fixed network from the specialized on the fixed network side and shield the fixed network from the
routing protocols; and (optionally) other internal Access Network specialized routing protocols; and (optionally) other internal Access
Routers which may also be needed in some cases to support the Network Routers which may also be needed in some cases to support the
protocols. The Access Network consists of the equipment needed to protocols. The Access Network consists of the equipment needed to
support this specialized routing, i.e. AR or ANG. AR and ANG may be support this specialized routing, i.e. AR or ANG. AR and ANG may be
the same physical nodes. the same physical nodes.
In addition, we present a few basic terms on mobile networks, that In addition, we present a few basic terms on mobile networks, that
is, mobile network, mobile router (MR), and mobile network node is, mobile network, mobile router (MR), and mobile network node
(MNN). More terminology for discussing mobile networks can be found (MNN). More terminology for discussing mobile networks can be found
in [15]. A more thorough discussion on mobile networks can be found in [15]. A more thorough discussion of mobile networks can be found
in the working group documents of the NEMO Working Group. in the working group documents of the NEMO Working Group.
Note: this reference architecture is not well suited for people Note: this reference architecture is not well suited for people
dealing with MANETs. dealing with Mobile Ad-hoc Networks (MANET).
| |
|
--- ------ ------- | --- ------ ------- |
--- | <--> | | -------| AR | -------------------| | | --- | <--> | | -------| AR | -------------------| | |
| |--[] --- /------ \ /| ANG |--| | |--[] --- /------ \ /| ANG |--|
--- AP / \ / | | | --- AP / \ / | | |
MH / \ / ------- | MH / \ / ------- |
(+wireless ___ / ------- | (with wireless ___ / ------- |
device) | |---- | ANR | | device) | |---- | ANR | |
--- ------- | --- ------- |
AP / \ | AP / \ |
/ \ ------- | / \ ------- |
--- ------ / \| | | --- ------ / \| | |
| |-------| AR |---------------------| ANG |--| | |-------| AR |---------------------| ANG |--|
--- ------ | | | --- ------ | | |
AP ------- | AP ------- |
| |
Access Network (AN) 1 | Access Network (AN) 1 |
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -| - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -|
Access Network (AN) 2 | Access Network (AN) 2 |
| |
| |
--- ------ ------- | --- ------ ------- |
--- | <--> | | -------| AR | -------------------| | | --- | <--> | | -------| AR | -------------------| | |
| |--[] --- /------ /| ANG |--| | |--[] --- /------ /| ANG |--|
--- AP / / | | | --- AP / / | | |
MH / / ------- | MH / / ------- |
(+wireless ___ / / | (with wireless ___ / / |
device) | |---- / | device) | |---- / |
--- / | --- / |
AP / | AP / |
/ | / |
| ------ --- ------ ------- | | --- ------ ------- |
--- |- i MR e <->| |-------| AR |---------| ANR | | --- | | <->| |-------| AR |---------| ANR | |
| |--| ------ --- \ ------ ------- | | |-| [] --- \ ------ ------- |
--- | AP \ / | --- | -----| AP \ / |
MNN | \ / | MNN |--i MR e \ / |
| --- \ ------ / | | ------ --- \ ------ / |
--- | | |-------| AR |------- | --- | (with | |-------| AR |------- |
| |--| --- ------ | | |-| wireless --- ------ |
--- | AP | --- | device) AP |
MNN 'i': MR ingress interface | MNN 'i': MR ingress interface |
'e': MR egress interface | 'e': MR egress interface |
| |
Figure 1: Reference Network Architecture Figure 1: Reference Network Architecture
Mobile Node (MN) Mobile Node (MN)
An IP node capable of changing its point of attachment to the An IP node capable of changing its point of attachment to the
network. A Mobile Node may either be a Mobile Host (no forwarding network. A Mobile Node may either be a Mobile Host (no forwarding
functionality) or a Mobile Router (forwarding functionality). functionality) or a Mobile Router (forwarding functionality).
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Fixed Node (FN) Fixed Node (FN)
A node, either a host or a router, unable to change its point of A node, either a host or a router, unable to change its point of
attachment to the network and its IP address without breaking attachment to the network and its IP address without breaking
open sessions. open sessions.
Mobile network Mobile network
An entire network, moving as a unit, which dynamically changes An entire network, moving as a unit, which dynamically changes
its point of attachment to the Internet and thus its reachability its point of attachment to the Internet and thus its reachability
in the topology. The mobile network is composed by one or more in the topology. The mobile network is composed of one or more
IP-subnets and is connected to the global Internet via one or IP-subnets and is connected to the global Internet via one or
more Mobile Routers (MR). The internal configuration of the more Mobile Routers (MR). The internal configuration of the
mobile network is assumed to be relatively stable with respect to mobile network is assumed to be relatively stable with respect to
the MR. the MR.
Mobile Router (MR) Mobile Router (MR)
A router capable of changing its point of attachment to the A router capable of changing its point of attachment to the
network, moving from one link to another link. The MR is capable network, moving from one link to another link. The MR is capable
of forwarding packets between two or more interfaces, and of forwarding packets between two or more interfaces, and
possibly running a dynamic routing protocol modifying the state possibly running a dynamic routing protocol modifying the state
by which to do packet forwarding. by which it does packet forwarding.
A MR acting as a gateway between an entire mobile network and the 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 rest of the Internet has one or more egress interface(s) and one
or more ingress interface(s). Packets forwarded upstream to the or more ingress interface(s). Packets forwarded upstream to the
rest of the Internet are transmitted through one of the MR's rest of the Internet are transmitted through one of the MR's
egress interface; packets forwarded downstream to the mobile egress interface; packets forwarded downstream to the mobile
network are transmitted through one of the MR's ingress network are transmitted through one of the MR's ingress
interface. interface.
Ingress interface Ingress interface
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The geographical area within which an Access Point provides radio The geographical area within which an Access Point provides radio
coverage, i.e. where radio communication between a Mobile Node coverage, i.e. where radio communication between a Mobile Node
and the specific Access Point is possible. and the specific Access Point is possible.
Access Network Router (ANR) Access Network Router (ANR)
An IP router in the Access Network. An Access Network Router may An IP router in the Access Network. An Access Network Router may
include Access Network specific functionalities, for example, include Access Network specific functionalities, for example,
related to mobility and/or QoS. This is to distinguish between related to mobility and/or QoS. This is to distinguish between
ordinary routers and routers that have Access Network-related ordinary routers and routers that have Access Network-related
special functionality. special functionality. An ANR is neither an AR nor an ANG.
Access Router (AR) Access Router (AR)
An Access Network Router residing on the edge of an Access An Access Network Router residing on the edge of an Access
Network and connected to one or more Access Points. The Access Network and connected to one or more Access Points. The Access
Points may be of different technology. An Access Router offers Points may be of different technology. An Access Router offers
IP connectivity to Mobile Nodes, acting as a default router to IP connectivity to Mobile Nodes, acting as a default router to
the Mobile Nodes it is currently serving. The Access Router may the Mobile Nodes it is currently serving. The Access Router may
include intelligence beyond a simple forwarding service offered include intelligence beyond a simple forwarding service offered
by ordinary IP routers. by ordinary IP routers.
Access Network Gateway (ANG) Access Network Gateway (ANG)
An Access Network Router that separates an Access Network from An Access Network Router that separates an Access Network from
other IP networks, much in the same way as an ordinary gateway other IP networks, much in the same way as an ordinary gateway
router. The Access Network Gateway looks to the other IP networks router. The Access Network Gateway looks to the other IP networks
like a standard IP router. 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) Access Network (AN)
An IP network which includes one or more Access Network Routers. An IP network which includes one or more Access Network Routers.
Administrative Domain (AD) Administrative Domain (AD)
A collection of networks under the same administrative control A collection of networks under the same administrative control
and grouped together for administrative purposes [5]. and grouped together for administrative purposes [5].
Serving Access Router (SAR) Serving Access Router (SAR)
The Access Router currently offering the connectivity to the MN. The Access Router currently offering the connectivity to the MN.
This is usually the point of departure for the MN as it makes its This is usually the point of departure for the MN as it makes its
way towards a new Access Router (then Serving Access Router takes way towards a new Access Router (at which time the Serving Access
the role of the Old Access Router). There may be several Serving Router takes the role of the Old Access Router). There may be
Access Routers serving the Mobile Node at the same time. several Serving Access Routers serving the Mobile Node at the
same time.
Old Access Router (OAR)
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.
New Access Router (NAR) New Access Router (NAR)
The Access Router that offers connectivity to the Mobile Node The Access Router that offers connectivity to the Mobile Node
after a handover. after a handover.
Previous Access Router (PAR) Previous Access Router (PAR)
An Access Router that offered connectivity to the Mobile Node An Access Router that offered connectivity to the Mobile Node
prior to a handover. This is the Serving Access Router that will prior to a handover. This is the Serving Access Router that will
cease or has ceased to offer connectivity to the Mobile Node. cease or has ceased to offer connectivity to the Mobile Node.
Same as OAR.
Candidate Access Router (CAR) Candidate Access Router (CAR)
An Access Router to which the Mobile Node may do a handoff. An Access Router to which the Mobile Node may do a handoff.
4. Handover Terminology 4. Handover Terminology
These terms refer to different perspectives and approaches to These terms refer to different perspectives and approaches to
supporting different aspects of mobility. Distinctions can be made supporting different aspects of mobility. Distinctions can be made
according to the scope, range overlap, performance characteristics, according to the scope, range overlap, performance characteristics,
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Roaming Roaming
An operator-based term involving formal agreements between An operator-based term involving formal agreements between
operators that allows a mobile to get connectivity from a foreign operators that allows a mobile to get connectivity from a foreign
network. Roaming (a particular aspect of user mobility) network. Roaming (a particular aspect of user mobility)
includes, for example, the functionality by which users can includes, for example, the functionality by which users can
communicate their identity to the local AN so that inter-AN communicate their identity to the local AN so that inter-AN
agreements can be activated and service and applications in the agreements can be activated and service and applications in the
MN's home network can be made available to the user locally. MN's home network can be made available to the user locally.
Handover Handover (also known as handoff)
(also known as handoff) the process by which an active MN (in the The process by which an active MN (in the Active State, see
Active State, see section 4.6) changes its point of attachment to section 4.6) changes its point of attachment to the network, or
the network, or when such a change is attempted. The access when such a change is attempted. The access network may provide
network may provide features to minimize the interruption to features to minimize the interruption to sessions in progress.
sessions in progress.
There are different types of handover classified according to There are different types of handover classified according to
different aspects involved in the handover. Some of this different aspects involved in the handover. Some of this
terminology follows the description of [4]. terminology follows the description in [4].
4.1. Scope of Handover 4.1. Scope of Handover
Note that the definitions of horizontal and vertical handover are
different than the ones commonly used today. These definitions try to
look at the handover from the IP layer's point of view; the IP layer
works with network interfaces, rather than specific technologies used
by those interfaces.
Layer 2 handover Layer 2 handover
A handover where the MN changes APs (or some other aspect of the 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 radio channel) connected to the same AR's interface. This type of
handover is transparent to the routing at the IP layer (or it handover is transparent to the routing at the IP layer (or it
appears simply as a link layer reconfiguration without any appears simply as a link layer reconfiguration without any
mobility implications). mobility implications).
Intra-AR handover Intra-AR handover
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A handover where the MN changes ARs inside the same AN. Such a A handover where the MN changes ARs inside the same AN. Such a
handover is not necessarily visible outside the AN. In case the handover is not necessarily visible outside the AN. In case the
ANG serving the MN changes, this handover is seen outside the AN 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 due to a change in the routing paths. Note that the ANG may
change for only some of the MN's data flows. change for only some of the MN's data flows.
Inter-AN handover Inter-AN handover
A handover where the MN moves to a new AN. This requires some A handover where the MN moves to a new AN. This requires some
sort of host mobility across ANs, which typically is be provided sort of host mobility ANs, which typically is be provided by the
by the external IP core. Note that this would have to involve the external IP core. Note that this would have to involve the
assignment of a new IP access address (e.g., a new care-of assignment of a new IP access address (e.g., a new care-of
address [9]) to the MN. address [9]) to the MN.
Intra-technology handover Intra-technology handover
A handover between equipment of the same technology. A handover between equipment of the same technology.
Inter-technology handover Inter-technology handover
A handover between equipment of different technologies. A handover between equipment of different technologies.
Horizontal handover Horizontal handover
A handover in which the mobile node's network interface does not This involves MNs moving between access points of the same type
change (from the IP point of view); the MN communicates with the (in terms of coverage, data rate and mobility), such as, UMTS to
access router via the same network interface before and after the UMTS, or WLAN to WLAN.
handover. A horizontal handover is typically also an intra-
technology handover but it can be an inter-technology handover if
the MN can do a layer 2 handover between two different
technologies without changing the network interface seen by the
IP layer.
Vertical handover Vertical handover
A handover in which the mobile node's network interface to the This involves MNs moving between access points of different type,
access network changes. A vertical handover is typically an such as, UMTS to WLAN.
inter-technology handover but it may also be an intra- technology
handover if the MN has several network interfaces of the same
type. That is, after the handover, the IP layer communicates with
the access network through a different network interface.
The different handover types defined in this section and in section Note that the difference between a horizontal and vertical handover
4.1 have no direct relationship. In particular, a MN can do an is vague. For example, a handover from an AP with 802.11b WLAN link
intra-AN handover of any of the types defined above. 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 that the horizontal and vertical handovers are not tied to a Note also that the IP layer sees network interfaces and IP addresses,
change in the link layer technology. They define whether, after a rather than specific technologies used by those interfaces. Thus,
handover, the IP packet flow goes through the same (horizontal horizontal and vertical handovers may or may not be noticed at the IP
handover) or a different (vertical handover) network interface. layer. Usually a handover can be noticed if the IP address assigned
These two handovers do not define whether the AR changes as a result to the interface changes, the network interface itself changes (which
of a handover. 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 4.2. Handover Control
A handover must be one of the following two types (a): A handover must be one of the following two types (a):
Mobile-initiated handover Mobile-initiated handover
the MN is the one that makes the initial decision to initiate the The MN is the one that makes the initial decision to initiate the
handover. handover.
Network-initiated handover Network-initiated handover
the network makes the initial decision to initiate the handover. The network makes the initial decision to initiate the handover.
A handover is also one of the following two types (b): A handover is also one of the following two types (b):
Mobile-controlled handover Mobile-controlled handover
The MN has the primary control over the handover process.
the MN has the primary control over the handover process.
Network-controlled handover Network-controlled handover
the network has the primary control over the handover process. The network has the primary control over the handover process.
A handover is also either of these three types (c): 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 Mobile-assisted handover
information and measurement from the MN are used by the AR to Information and measurement from the MN are used by the AR to
decide on the execution of a handover. decide on the execution of a handover.
Network-assisted handover Network-assisted handover
a handover where the AN collects information that can be used by A handover where the AN collects information that can be used by
the MN in a handover decision. the MN in a handover decision.
Unassisted handover Unassisted handover
a handover where no assistance is provided by the MN or the AR to A handover where no assistance is provided by the MN or the AR to
each other. each other.
Note that it is possible that the MN and the AR both do Note that it is possible that the MN and the AR both do measurements
measurements and decide on the handover. and decide on the handover.
A handover is also one of the following two types (d): A handover is also one of the following two types (d):
Backward handover Push handover
a handover either initiated by the OAR, or where the MN initiates A handover either initiated by the PAR, or where the MN initiates
a handover via the OAR. a handover via the PAR.
Forward handover Pull handover
a handover either initiated by the NAR, or where the MN initiates A handover either initiated by the NAR, or where the MN initiates
a handover via the NAR. a handover via the NAR.
The handover is also either proactive or reactive (e): The handover is also either proactive or reactive (e):
Planned handover Planned handover
a proactive (expected) handover where some signalling can be done A proactive (expected) handover where some signaling can be done
in advance of the MN getting connected to the new AR, e.g. in advance of the MN getting connected to the new AR, e.g.
building a temporary tunnel from the old AR to the new AR. building a temporary tunnel from the previous AR to the new AR.
Unplanned handover Unplanned handover
a reactive (unexpected) handover, where no signalling is done in A reactive (unexpected) handover where no signaling is done in
advance of the MN's move of the OAR to the new AR. advance of the MN's move of the previous AR to the new AR.
The five handover types (a-e) are mostly independent, and every The five handover types (a-e) are mostly independent, and every
handover should be classiable according to each of these types. handover should be classifiable according to each of these types.
4.3. Simultaneous connectivity to Access Routers 4.3. Simultaneous connectivity to Access Routers
Make-before-break (MBB) Make-before-break (MBB)
During a MBB handover the MN can communicate simultaneously with During a MBB handover the MN makes the new connection before the
the old and new AR. This should not be confused with "soft old one is broken. Thus, the MN can communicate simultaneously
handover" which relies on macro diversity. 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) Break-before-make (BBM)
During a BBM handover the MN cannot communicate simultaneously During a BBM handover the MN breaks the old connection before the
with the old and the new AR. new connection is made. Thus the MN cannot communicate
simultaneously with the old and the new AR.
4.4. Performance and Functional Aspects 4.4. Performance and Functional Aspects
Handover latency Handover latency
Handover latency is the time difference between when a MN is last 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 OAR, until able to send and/or receive an IP packet by way of the PAR, and
when the MN is able to send and/or receive an IP packet through the time the MN is able to send and/or receive an IP packet
the NAR. Adapted from [4]. through the NAR. Adapted from [4].
Smooth handover Smooth handover
A handover that aims primarily to minimize packet loss, with no A handover that aims primarily to minimize packet loss, with no
explicit concern for additional delays in packet forwarding. explicit concern for additional delays in packet forwarding.
Fast handover Fast handover
A handover that aims primarily to minimize delay, with no A handover that aims primarily to minimize handover latency, with
explicit interest in packet loss. no explicit interest in packet loss.
Seamless handover Seamless handover
A handover in which there is no change in service capability, A handover in which there is no change in service capability,
security, or quality. In practice, some degradation in service security, or quality. In practice, some degradation in service is
is to be expected. The definition of a seamless handover in the to be expected. The definition of a seamless handover in the
practical case should be that other protocols, applications, or practical case should be that other protocols, applications, or
end users do not detect any change in service capability, end users do not detect any change in service capability,
security or quality, which would have a bearing on their (normal) security or quality, which would have a bearing on their (normal)
operation. See [7] for more discussion on the topic. 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 Throughput
The amount of data from a source to a destination processed by The amount of data from a source to a destination processed by
the protocol for which throughput is to be measured for instance, the protocol for which throughput is to be measured for instance,
IP, TCP, or the MAC protocol. The throughput differs between IP, TCP, or the MAC protocol. The throughput differs between
protocol layers. protocol layers.
Goodput Goodput
The total bandwidth used, less the volume of control messages, The total bandwidth used, less the volume of control messages,
protocol overhead from the data packets, and packets dropped due protocol overhead from the data packets, and packets dropped due
to CRC errors. to CRC errors.
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medium constituting the link. medium constituting the link.
Hidden-terminal problem Hidden-terminal problem
The problem whereby a transmitting node can fail in its attempt The problem whereby a transmitting node can fail in its attempt
to transmit data because of destructive interference which is to transmit data because of destructive interference which is
only detectable at the receiving node, not the transmitting node. only detectable at the receiving node, not the transmitting node.
Exposed terminal problem Exposed terminal problem
The problem whereby a transmitting node prevents another node The problem whereby a transmitting node A prevents another node B
from transmitting although it could have safely transmitted to from transmitting, although node B could have safely transmitted
anyone else but that node. to anyone else but the transmitting node A.
4.5. Micro Diversity, Macro Diversity, and IP Diversity 4.5. Micro Diversity, Macro Diversity, and IP Diversity
Certain air interfaces (e.g. the Universal Mobile Telephone System Certain air interfaces (e.g. the Universal Mobile Telephone System
(UMTS) Terrestial Radio Access Network (UTRAN) running in Frequency (UMTS) Terrestrial Radio Access Network (UTRAN) running in Frequency
Division Duplex (FDD) mode) require or at least support macro Division Duplex (FDD) mode) require or at least support macro
diversity combining. Essentially, this refers to the fact that a diversity combining. Essentially, this refers to the fact that a
single MN is able to send and receive over two independent radio single MN is able to send and receive over two independent radio
channels ('diversity branches') at the same time; the information channels ('diversity branches') at the same time; the information
received over different branches is compared and that from the better received over different branches is compared and that from the better
branch passed to the upper layers. This can be used both to improve branch passed to the upper layers. This can be used both to improve
overall performance, and to provide a seamless type of handover at 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. layer 2, since a new branch can be added before the old is deleted.
See also [6]. See also [6].
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Macro diversity Macro diversity
Duplicating or combining actions taking place over multiple APs, Duplicating or combining actions taking place over multiple APs,
possibly attached to different ARs. This may require support possibly attached to different ARs. This may require support
from the network layer to move the radio frames between the base from the network layer to move the radio frames between the base
stations and a central combining point. stations and a central combining point.
IP diversity IP diversity
The splitting and combining of packets at the IP level. 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.
4.6. Paging, and Mobile Node States and Modes 4.6. Paging, and Mobile Node States and Modes
Mobile systems may employ the use of MN states in order to operate Mobile systems may employ the use of MN states in order to operate
more efficiently without degrading the performance of the system. The more efficiently without degrading the performance of the system. The
term 'mode' is also common and means the same as 'state'. term 'mode' is also common and means the same as 'state'.
A MN is always in one of the following three states: A MN is always in one of the following three states:
Active state Active state
When the AN knows the MN's SAR and the MN can send and receive IP When the AN knows the MN's SAR and the MN can send and receive IP
packets. The AL may not be active, but the radio layer is able packets. The access link may not be active, but the radio layer
to establish one without assistance from the network layer. The is able to establish one without assistance from the network
MN has an IP address assigned. layer. The MN has an IP address assigned.
Dormant state Dormant state
A state in which the mobile restricts its ability to receive A state in which the mobile restricts its ability to receive
normal IP traffic by reducing its monitoring of radio channels. 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 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 packets cannot be delivered to the MN without the AN initiating
paging. paging. Often also called Idle state.
Time-slotted dormant mode Time-slotted dormant mode
A dormant mode implementation in which the mobile alternates A dormant mode implementation in which the mobile alternates
between periods of not listening for any radio traffic and between periods of not listening for any radio traffic and
listening for traffic. Time-slotted dormant mode implementations listening for traffic. Time-slotted dormant mode implementations
are typically synchronized with the network so the network can are typically synchronized with the network so the network can
deliver traffic to the mobile during listening periods. deliver paging messages to the mobile during listening periods.
Inactive state Inactive state
the MN is in neither the Active nor Dormant State. The MN is no the MN is in neither the Active nor Dormant State. The MN is no
longer listening for any packets, not even periodically, and not longer listening for any packets, not even periodically, and not
sending packets. The MN may be in a powered off state, it may sending packets. The MN may be in a powered off state, it may
have shut down all interfaces to drastically conserve power, or 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 it may be out of range of a radio access point. The MN does not
necessarily have an IP access address from the AN. necessarily have an IP access address from the AN.
Note: in fact, as well as the MN being in one of these three states, 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 the AN also stores which state it believes the MN is in. Normally
these are consistent; the definitions above assume so. these are consistent; the definitions above assume so.
Here are some additional definitions for paging, taking into account Here are some additional definitions for paging, taking into account
the above state definitions. the above state definitions.
Paging Paging
A procedure initiated by the Access Network to move an Idle MN A procedure initiated by the Access Network to move a Dormant MN
into the Active State. As a result of paging, the MN establishes into the Active State. As a result of paging, the MN establishes
a SAR and the IP routes are set up. a SAR and the IP routes are set up.
Location updating Location updating
A procedure initiated by the MN, by which it informs the AN that A procedure initiated by the MN, by which it informs the AN that
it has moved into a new paging area. it has moved into a new paging area.
Paging area Paging area
A part of the Access Network, typically containing a number of A part of the Access Network, typically containing a number of
ARs/APs, which corresponds to some geographical area. The AN ARs/APs, which corresponds to some geographical area. The AN
keeps and updates a list of all the Idle MNs present in the area. keeps and updates a list of all the Dormant MNs present in the
If the MN is within the radio coverage of the area it will be area. If the MN is within the radio coverage of the area it will
able to receive paging messages sent within that Paging Area. be able to receive paging messages sent within that Paging Area.
Paging area registrations Paging area registrations
Signaling from a dormant mode mobile node to the network, by Signaling from a dormant mode mobile node to the network, by
which it establishes its presence in a new paging area. Paging which it establishes its presence in a new paging area. Paging
Area Registrations thus enable the network to maintain a rough Area Registrations thus enable the network to maintain a rough
idea of where the mobile is located. idea of where the mobile is located.
Paging channel Paging channel
A radio channel dedicated to signaling dormant mode mobiles for A radio channel dedicated to signaling dormant mode mobiles for
paging purposes. By current practice, the protocol used on a paging purposes. By current practice, the paging channel carries
paging channel is usually dictated by the radio link protocol, only control traffic necessary for the radio link, although some
although some paging protocols have provision for carrying paging protocols have provision for carrying arbitrary traffic
arbitrary traffic (and thus could potentially be used to carry (and thus could potentially be used to carry IP).
IP).
Traffic channel Traffic channel
The radio channel on which IP traffic to an active mobile is The radio channel on which IP traffic to an active mobile is
typically sent. This channel is used by a mobile that is typically sent. This channel is used by a mobile that is
actively sending and receiving IP traffic, and is not actively sending and receiving IP traffic, and is not
continuously active in a dormant mode mobile. For some radio continuously active in a dormant mode mobile. For some radio
link protocols, this may be the only channel available. link protocols, this may be the only channel available.
4.7. Context Transfer 4.7. Context Transfer
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usually requires a protocol exchange with the MN. An example of a usually requires a protocol exchange with the MN. An example of a
routing-related service is header compression. The service may routing-related service is header compression. The service may
also be indirectly related to routing, for example, security. also be indirectly related to routing, for example, security.
Security may not affect the forwarding decision of all Security may not affect the forwarding decision of all
intermediate routers, but a packet may be dropped if it fails a intermediate routers, but a packet may be dropped if it fails a
security check (can't be encrypted, authentication failed, etc.). security check (can't be encrypted, authentication failed, etc.).
Dropping the packet is basically a routing decision. Dropping the packet is basically a routing decision.
4.8. Candidate Access Router Discovery 4.8. Candidate Access Router Discovery
Capability of AR Capability of an AR
A characteristic of the service offered by an AR that may be of 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 interest to an MN when the AR is being considered as a handoff
candidate. candidate.
Candidate AR (CAR) Candidate AR (CAR)
An AR to which MN has a choice of performing IP-level handoff. 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 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 AP that is served by this AR, as well as the coverage of this AR
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Target AR (TAR) Target AR (TAR)
An AR with which the procedures for the MN's IP-level handoff are An AR with which the procedures for the MN's IP-level handoff are
initiated. TAR is selected after running a TAR Selection initiated. TAR is selected after running a TAR Selection
Algorithm that takes into account the capabilities of CARs, Algorithm that takes into account the capabilities of CARs,
preferences of MN and any local policies. preferences of MN and any local policies.
4.9. Types of Mobility 4.9. Types of Mobility
Different sorts of mobility management may be required of a mobile We can differentiate between host and network mobility, and various
system. We can differentiate between personal, host and network types of network mobility. Terminology related more to applications
mobility. such as the Session Initiation Protocol, such as personal mobility,
is out of scope for this document.
Personal mobility support
Provides the ability to track the user's location and provide the
user's current location to allow sessions to be initiated by and
towards the user by anyone on any other network. Personal
mobility is also concerned with enabling associated security,
billing and service subscription authorization made between
administrative domains.
Host mobility support Host mobility support
Refers to the function of allowing a mobile node to change its Refers to the function of allowing a mobile node to change its
point of attachment to the network, without interrupting IP point of attachment to the network, without interrupting IP
packet delivery to/from that node. There may be different sub- packet delivery to/from that node. There may be different sub-
functions depending on what the current level of service is being functions depending on what the current level of service is being
provided; in particular, support for host mobility usually provided; in particular, support for host mobility usually
implies active and idle modes of operation, depending on whether implies active and dormant modes of operation, depending on
the node has any current sessions or not. Access Network whether the node has any current sessions or not. Access Network
procedures are required to keep track of the current point of procedures are required to keep track of the current point of
attachment of all the MNs or establish it at will. Accurate attachment of all the MNs or establish it at will. Accurate
location and routing procedures are required in order to maintain location and routing procedures are required in order to maintain
the integrity of the communication. Host mobility is often called the integrity of the communication. Host mobility is often
'terminal mobility'. called 'terminal mobility'.
Network mobility support Network mobility support
Refers to the function of allowing an entire network to change Refers to the function of allowing an entire network to change
its point of attachment to the Internet, and, thus, its its point of attachment to the Internet, and, thus, its
reachability in the topology, without interrupting IP packet reachability in the topology, without interrupting IP packet
delivery to/from that mobile network. delivery to/from that mobile network.
Two subcategories of mobility can be identified withing either host Two subcategories of mobility can be identified within both host
mobility and network mobility: mobility and network mobility:
Global mobility Global mobility
Same as Macro mobility. Same as Macro mobility.
Local mobility Local mobility
Same as Micro mobility. Same as Micro mobility.
skipping to change at page 23, line 15 skipping to change at page 23, line 12
MN moves between IP domains. Inter-AN handovers typically involve MN moves between IP domains. Inter-AN handovers typically involve
macro-mobility protocols. Mobile-IP can be seen as a means to macro-mobility protocols. Mobile-IP can be seen as a means to
provide macro mobility. provide macro mobility.
Micro mobility Micro mobility
Mobility over a small area. Usually this means mobility within Mobility over a small area. Usually this means mobility within
an IP domain with an emphasis on support for active mode using an IP domain with an emphasis on support for active mode using
handover, although it may include idle mode procedures also. handover, although it may include idle mode procedures also.
Micro-mobility protocols exploit the locality of movement by Micro-mobility protocols exploit the locality of movement by
confining movement related changes and signalling to the access confining movement related changes and signaling to the access
network. network.
Local mobility management Local mobility management
Local mobility management (LMM) is a generic term for protocols Local mobility management (LMM) is a generic term for protocols
dealing with IP mobility management confined within the access dealing with IP mobility management confined within the access
network. LMM messages are not routed outside the access network, network. LMM messages are not routed outside the access network,
although a handover may trigger Mobile IP messages to be sent to although a handover may trigger Mobile IP messages to be sent to
correspondent nodes and home agents. correspondent nodes and home agents.
5. Specific Terminology for Mobile Ad-Hoc Networking 5. Specific Terminology for Mobile Ad-Hoc Networking
Cluster Cluster
A group of nodes located within close physical proximity, A group of nodes located within close physical proximity,
typically all within range of one another, which can be grouped typically all within range of one another, which can be grouped
together for the purpose of limiting the production and together for the purpose of limiting the production and
propogation of routing information. propagation of routing information.
Cluster head Cluster head
A cluster head is a node (often elected in the cluster formation A cluster head is a node (often elected in the cluster formation
process) that has complete knowledge about group membership and process) that has complete knowledge about group membership and
link state information in the cluster. Each cluster should have link state information in the cluster. Each cluster should have
one and only one cluster head. one and only one cluster head.
Cluster member Cluster member
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6. Security-related Terminology 6. Security-related Terminology
This section includes terminology commonly used around mobile and This section includes terminology commonly used around mobile and
wireless networking. Only a mobility-related subset of the entire wireless networking. Only a mobility-related subset of the entire
security terminology is presented. security terminology is presented.
Authorization-enabling extension Authorization-enabling extension
An authentication which makes a (registration) message acceptable An authentication which makes a (registration) message acceptable
to the ultimate recipient of the registration message. An to the ultimate recipient of the registration message. An
authorization-enabling extension must contain an SPI [12]. authorization-enabling extension must contain an SPI (see below)
[12].
Mobility security association Mobility security association
A collection of security contexts, between a pair of nodes, which A collection of security contexts, between a pair of nodes, which
may be applied to mobility-related protocol messages exchanged may be applied to mobility-related protocol messages exchanged
between them. In Mobile IP, each context indicates an between them. In Mobile IP, each context indicates an
authentication algorithm and mode, a secret (a shared key, or authentication algorithm and mode, a secret (a shared key, or
appropriate public/private key pair), and a style of replay appropriate public/private key pair), and a style of replay
protection in use. Mobility security associations may be stored protection in use. Mobility security associations may be stored
separately from the node's IPsec Security Policy Database (SPD) separately from the node's IPsec Security Policy Database (SPD)
[12]. [12].
Registration key Registration key
A key used as the basis of a Mobility Security Association A key used in the Mobility Security Association between a mobile
between a mobile node and a foreign agent. A registration key is node and a foreign agent. A registration key is typically only
typically only used once or a very few times, and only for the used once or a very few times, and only for the purposes of
purposes of verifying a small volume of Authentication data [14]. verifying a small volume of Authentication data [14].
Security context Security context
A security context between two routers defines the manner in A security context between two nodes defines the manner in which
which two routers choose to mutually authenticate each other, and two nodes choose to mutually authenticate each other, and
indicates an authentication algorithm and mode. indicates an authentication algorithm and mode.
Security Parameter Index (SPI) Security Parameter Index (SPI)
An index identifying a security context between a pair of routers An index identifying a security context between a pair of routers
among the contexts possible in the mobility security association. among the contexts available in the mobility security
association.
Stale challenge
Any challenge that has been used by the mobile node in a
Registration Request message and processed by the Foreign Agent
by relaying or generating The Foreign Agent may not be able to
keep records for all previously used challenges [13].
Unknown challenge
Any challenge from a particular mobile node that the foreign
agent has no record of having put either into one of its recent
Agent Advertisements or into a registration reply message to that
mobile node [13].
Unused challenge
A challenge that has not been already accepted by the Foreign
Agent challenge in a corresponding Registration Reply message --
i.e., a challenge that is neither unknown nor previously used
[13].
The Mobile IPv6 specification includes more security terminology The Mobile IPv6 specification includes more security terminology
related to MIPv6 bindings [11]. related to MIPv6 bindings [11]. Terminology about the MIP
challenge/response mechanism can be found in [13].
7. Security Considerations 7. Security Considerations
This document presents only terminology. There are no security issues This document presents only terminology. There are no security issues
in this document. in this document.
8. Contributors 8. Contributors
This draft was initially based on the work of This draft was initially based on the work of
skipping to change at page 26, line 9 skipping to change at page 25, line 37
o Nikos Georganopoulos, King's College London o Nikos Georganopoulos, King's College London
o Markku Kojo and Jukka Manner, University of Helsinki, Finland. o Markku Kojo and Jukka Manner, University of Helsinki, Finland.
Since revision -02 of the document draft-manner-seamoby-terms-02.txt, Since revision -02 of the document draft-manner-seamoby-terms-02.txt,
Charles Perkins has given as input terminology related to ad-hoc Charles Perkins has given as input terminology related to ad-hoc
networks. networks.
Thierry Ernst has provided the terminology for discussing mobile Thierry Ernst has provided the terminology for discussing mobile
networks. networks.
9. Change log Henrik Levkowetz did a final check of the definitions in revision -05
and suggested a number of changes.
Changes from -04
- Removed User mobility, and related discussions elsewhere
- Added terms to Appendix B
- Capitalizing fixes
- Added "Subnet"
- Clarified "link" and gave pointer to "access link"
- Added "(HoA)" to "Home Address"
- Refined definition of Mobile Node (added MH and MR)
- Separated ingress and egress interfaces from the definition of MR
- Revised use of terms MN/MH/node/host
- minor edits
Changes from -03
- Added comments from Randy Presuhn and Thierry Ernst
Changes from -02
- Updated the terminology related to mobile networks
Changes from -01
- Added security terminology
- Miscellaneous small refinements of definitions
Changes from -00
- Added definition for Routing Proxy
- Added basic terminology about mobile networks
- Added Link-Layer Trigger from FMIPv6
- Edited the CAR terminology section
- Added definitions for MPR, CoA, BU
- Changed the definition of Home Address
- Added a mobile network into Figure 1
- Edited the Network Components section
10. Acknowledgement 9. Acknowledgments
This work has been partially performed in the framework of the IST This work has been partially performed in the framework of the IST
project IST-2000-28584 MIND, which is partly funded by the European project IST-2000-28584 MIND, which is partly funded by the European
Union. Some of the authors would like to acknowledge the help of Union. Some of the authors would like to acknowledge the help of
their colleagues in preparing this document. their colleagues in preparing this document.
Randy Presuhn did a very thorough and helpful review of the -02 Randy Presuhn did a very thorough and helpful review of the -02
version of the terminology. version of the terminology.
Some definitions of terminology have been adapted from [1], [7], [3], Some definitions of terminology have been adapted from [1], [7], [3],
[2], [4], [9], [10], [11] and [12]. [2], [4], [9], [10], [11] and [12].
11. Informative References 10. Informative References
[1] Blair, D., Tweedly, A., Thomas, M., Trostle, J. and [1] Blair, D., Tweedly, A., Thomas, M., Trostle, J. and
Ramalho, M., "Realtime Mobile IPv6 Framework", Work in Ramalho, M., "Realtime Mobile IPv6 Framework", Work in
Progress. Progress.
[2] Calhoun, P., Montenegro, G. and Perkins, C., "Mobile IP [2] Calhoun, P., Montenegro, G. and Perkins, C., "Mobile IP
Regionalized Tunnel Management", Work in Progress. Regionalized Tunnel Management", Work in Progress.
[3] Deering, S. and Hinden, R., "Internet Protocol, Version 6 [3] Deering, S. and Hinden, R., "Internet Protocol, Version 6
(IPv6) Specification". RFC 2460, December 1998. (IPv6) Specification". RFC 2460, December 1998.
skipping to change at page 28, line 6 skipping to change at page 26, line 58
[13] Perkins, C., Calhoun, P. and Bharatia, J., "Mobile [13] Perkins, C., Calhoun, P. and Bharatia, J., "Mobile
IPv4 Challenge/Response Extensions (revised)", Work in IPv4 Challenge/Response Extensions (revised)", Work in
Progress. Progress.
[14] Perkins, C. and Calhoun, P., "AAA Registration Keys for Mobile [14] Perkins, C. and Calhoun, P., "AAA Registration Keys for Mobile
IP", Work in Progress. IP", Work in Progress.
[15] Ernst, T. and Lach, H., "Network Mobility Support [15] Ernst, T. and Lach, H., "Network Mobility Support
Terminology", Work in Progress. Terminology", Work in Progress.
12. Authors' Addresses [16] Moy, J., OSPF Version 2. RFC 2328, April 1998.
Questions about this document may be directed to: 11. Authors' Addresses
Jukka Manner Jukka Manner
Department of Computer Science Department of Computer Science
University of Helsinki University of Helsinki
P.O. Box 26 (Teollisuuskatu 23) P.O. Box 26 (Teollisuuskatu 23)
FIN-00014 HELSINKI FIN-00014 HELSINKI
Finland Finland
Voice: +358-9-191-44210 Voice: +358-9-191-44210
Fax: +358-9-191-44441 Fax: +358-9-191-44441
skipping to change at page 30, line 5 skipping to change at page 29, line 5
Nikos Georganopoulos Nikos Georganopoulos
King's College London King's College London
Strand Strand
London WC2R 2LS London WC2R 2LS
United Kingdom United Kingdom
Voice: +44-20-78482889 Voice: +44-20-78482889
Fax: +44-20-78482664 Fax: +44-20-78482664
E-Mail: nikolaos.georganopoulos@kcl.ac.uk E-Mail: nikolaos.georganopoulos@kcl.ac.uk
13. Appendix A - Examples 12. Appendix A - Index of Terms
This appendix provides examples for the terminology presented.
A.1. Mobility
Host mobility is logically independent of the mobility of users,
although in real networks, at least the address management functions
are often required to initially attach the MN to the network. In
addition, if the network wishes to determine whether access is
authorized (and if so, who to charge for it), then this may be tied
to the identity of the user of the terminal.
Personal mobility support typically amounts to the maintenance and
update of some sort of address mapping database, such as a SIP server
or DNS server; it is also possible for the personal mobility support
function to take a part in forwarding control messages between end
user and correspondent rather than simply acting as a database. SIP
is a protocol for session initiation in IP networks. It includes
registration procedures which partially support personal mobility
(namely, the ability for the network to route a session towards a
user at a local IP address).
Personal mobility has been defined in [8] as "the ability of end
users to originate and receive calls and access subscribed
telecommunication services on any terminal in any location, and the
ability of the network to identify end users as they move. Personal
mobility is based on the use of a unique personal identity (i.e.,
personal number)."
Roaming, in its original (GSM) sense, is the ability of a user to
connect to the networks owned by operators other than the one having
a direct formal relationship with the user. More recently (e.g., in
data networks and UMTS) it also refers providing user-customized
services in foreign networks (e.g., QoS profiles for specific
applications).
HAWAII, Cellular IP, Regional Registration and Edge Mobility
Architecture (EMA) are examples of micro mobility schemes, with the
assumption that Mobile IP is used for macro mobility.
Public Land Mobile Networks (GSM/UMTS) typically have extensive
support for both user and host mobility. Complete sets of protocols
(both over the air and on the network side) are provided for user
mobility, including customized service provision. Handover for host
mobility is also supported, both within access networks, and also
within the GSM/UMTS core network for mobility between access networks
of the same operator.
A.2. Handovers
A hard handover is required where a MN is not able to receive or send
traffic from/to two APs simultaneously. In order to move the traffic
channel from the old to the new access point the MN abruptly changes
the frequency/timeslot/code on which it is transmitting and listening
to new values associated with a new access point. Thus, the handover
is a break-before-make handover.
A good example of hard handover is GSM where the mobile listens for
new base stations, reports back to the network the signal strength
and identity of the new base station(s) heard. When the old base
station decides that a handover is required it instructs the new base
station to set up resources and, when confirmed, instructs the mobile
to switch to a new frequency and time slot. This sort of hand over
is called hard, mobile assisted, network initiated and backward
(meaning that the old base station is responsible for handling the
change-over).
In a Time-Division Multiple Access (TDMA) system, such as GSM, the
hard hand over is delayed until the mobile has moved well within the
coverage of the new base station. If the handover threshold was set
to the point where the new base station signal exceeded the old then
there would be a very large number of handovers as the mobile moved
through the region between the cells and radio signals fluctuated,
this would create a large signalling traffic. To avoid this a large
hysteresis is set, i.e. the new base station must be (say) 10dB
stronger for handover to occur. If the same was done in Wideband
Carrier Division Multiple Access (W-CDMA) then the mobile would be
transmitting a powerful signal to the old base station and creating
interference for other users, since in CDMA everyone else's
transmissions are seen as noise, thus reducing capacity. To avoid
this soft handover is used, giving an estimated doubling in capacity.
Support for soft handover (in a single mode terminal) is
characteristic of radio interfaces which also require macro diversity
for interference limitation but the two concepts are logically
independent.
A good example of soft handover is the UTRAN FDD mode. W-CDMA is
particularly suited to soft handover because of the design of the
receivers and transmitters: typically a rake receiver will be used
to overcome the multi-path fading of the wide-band channel. Rake
receivers have a number of so-called fingers, each effectively
separate detectors, that are tuned to the same signal (e.g.
spreading code) but delayed by different times. When the delay times
are correctly adjusted and the various components properly combined
(this is micro diversity combining) the effect of multi-path fading
is removed. The rake receiver can also be used to detect signals
from different transmitters by tuning the fingers to different
spreading codes. Soft handover is used in UTRAN FDD mode to also
increase capacity.
Every handover can be seen as a context-aware Handover. In PLMNs the
context to be fulfilled is that the new AP can accommodate the new
mobile, for example, the new GSM cell can serve the incoming phone.
Lately, the notion of Context-aware Handovers has been enlarged by,
for example, QoS-aware handovers, meaning that the handover is
governed by the need to support the QoS-context of the moving mobile
in order to keep the service level assured to the user of the MN.
A.3. Diversity combining
In the case of UMTS it is radio frames that are duplicated at some
point in the network, at the serving Radio Network Controller (RNC),
and sent to a number of basestations and, possibly via other (drift)
RNCs. The combining that takes place at the serving RNC in the uplink
direction is typically based on some simple quality comparison of the
various received frames, which implies that the various copies of
these frames must contain identical upper layer information. The
serving RNC also has to do buffering data frames to take account of
the differing time of flight from each basestation to the RNC.
A.4. Miscellaneous
In a GPRS/UMTS system the Access Network Gateway node could be the
GGSN component. The ANG can provide support for mobility of hosts,
admission control, policy enforcement, and Foreign Agent
functionality [9].
When presenting a mobile network topology, APs and ARs are usually
pictured as separate components (see Figure 1). This is the case
with GSM/GPRS/UMTS presentations, for example. From the IP point of
view APs are not directly visible. An AP should only be seen from
the MN's or AR's IP layer as a link (interface) connecting MNs to the
AR.
When the mobile moves through the network, depending on the mobility
mechanism, the OAR will forward packets destined to the old MNs
address to the SAR which currently serves the MN. At the same time
the handover mechanism may be studying CARs to find the best NAR
where the MN will be handed next.
14. Appendix B - Index of Terms
Access Link (AL) ............................................... 12 AD ............................................................. 13
Access Network (AN) ............................................ 13 AL ............................................................. 12
Access Network Gateway (ANG) ................................... 12 AN ............................................................. 13
Access Network Router (ANR) .................................... 12 ANG ............................................................ 12
Access Point (AP) .............................................. 12 ANR ............................................................ 12
Access Router (AR) ............................................. 12 AP ............................................................. 12
AR ............................................................. 12
Access Link .................................................... 12
Access Network ................................................. 13
Access Network Gateway ......................................... 12
Access Network Router .......................................... 12
Access Point ................................................... 12
Access Router .................................................. 12
Active state ................................................... 19 Active state ................................................... 19
Administrative Domain (AD) ..................................... 13 Administrative Domain .......................................... 13
Asymmetric link ................................................. 5 Asymmetric link ................................................. 5
Authorization-enabling extension ............................... 24 Authorization-enabling extension ............................... 24
Backward handover .............................................. 16 BBM ............................................................ 17
BU .............................................................. 3
Bandwidth ....................................................... 3 Bandwidth ....................................................... 3
Bandwidth utilization ........................................... 3 Bandwidth utilization ........................................... 3
Beacon .......................................................... 3 Beacon .......................................................... 3
Binding Update (BU) ............................................. 3 Binding Update .................................................. 3
Break-before-make (BBM) ........................................ 17 Break-before-make .............................................. 17
Candidate AR (CAR) ............................................. 21 CAR ............................................................ 13
Candidate Access Router (CAR) .................................. 13 CAR ............................................................ 21
Capability of AR ............................................... 21 Candidate AR ................................................... 21
Care-of-Address (CoA) ........................................... 3 Candidate Access Router ........................................ 13
Capability of an AR ............................................ 21
Care-of-Address ................................................. 3
Channel ......................................................... 3 Channel ......................................................... 3
Channel access protocol ......................................... 3 Channel access protocol ......................................... 3
Channel capacity ................................................ 3
Cluster ........................................................ 23 Cluster ........................................................ 23
Cluster head ................................................... 23 Cluster head ................................................... 23
Cluster member ................................................. 23 Cluster member ................................................. 23
CoA ............................................................. 3
Context ........................................................ 21 Context ........................................................ 21
Context transfer ............................................... 21 Context transfer ............................................... 21
Control message ................................................. 3 Control message ................................................. 4
Convergence .................................................... 23 Convergence .................................................... 23
Convergence time ............................................... 24 Convergence time ............................................... 23
Distance vector ................................................. 4 Distance vector ................................................. 4
Dormant state .................................................. 19 Dormant state .................................................. 19
Egress interface ............................................... 11 Egress interface ............................................... 11
Exposed terminal problem ....................................... 18 Exposed terminal problem ....................................... 18
FN ............................................................. 11
Fairness ........................................................ 4 Fairness ........................................................ 4
Fast handover .................................................. 17 Fast handover .................................................. 17
Feature context ................................................ 21 Feature context ................................................ 21
Fixed Node (FN) ................................................ 11 Fixed Node ..................................................... 11
Flooding ........................................................ 4 Flooding ........................................................ 4
Foreign subnet prefix ........................................... 4 Foreign subnet prefix ........................................... 4
Forward handover ............................................... 16
Forwarding node ................................................. 4 Forwarding node ................................................. 4
Global mobility ................................................ 22 Global mobility ................................................ 22
Goodput ........................................................ 18 Goodput ........................................................ 18
HA .............................................................. 4
Handoff ........................................................ 14
Handover ....................................................... 14 Handover ....................................................... 14
Handover latency ............................................... 17 Handover latency ............................................... 17
Hidden-terminal problem ........................................ 18 Hidden-terminal problem ........................................ 18
Home Address (HoA) .............................................. 4 HoA ............................................................. 4
Home subnet prefix .............................................. 4 Home Address .................................................... 4
Home Agent ...................................................... 4
Home subnet prefix .............................................. 5
Horizontal Handover ............................................ 15 Horizontal Handover ............................................ 15
Host mobility support .......................................... 22 Host mobility support .......................................... 22
IP access address ............................................... 4 IP access address ............................................... 5
IP diversity ................................................... 19 IP diversity ................................................... 19
Inactive state ................................................. 19 Inactive state ................................................. 19
Ingress interface .............................................. 11 Ingress interface .............................................. 11
Inter-AN handover .............................................. 14 Inter-AN handover .............................................. 14
Interface ....................................................... 4 Inter-technology handover ...................................... 14
Inter-technology handover ...................................... 15 Interface ....................................................... 5
Intra-AN handover .............................................. 14 Intra-AN handover .............................................. 14
Intra-AR handover .............................................. 14 Intra-AR handover .............................................. 14
Intra-technology handover ...................................... 15 Intra-technology handover ...................................... 14
L2 Trigger ...................................................... 5
Laydown ........................................................ 24 Laydown ........................................................ 24
Layer 2 handover ............................................... 14 Layer 2 handover ............................................... 14
Link ............................................................ 5 Link ............................................................ 5
Link establishment .............................................. 5 Link establishment .............................................. 5
Link state ...................................................... 5 Link state ...................................................... 6
Link-layer trigger (L2 Trigger) ................................. 5 Link-layer trigger .............................................. 5
Link-level acknowledgement ...................................... 5 Link-level acknowledgment ....................................... 6
Local broadcast ................................................. 6 Local broadcast ................................................. 6
Local mobility ................................................. 22 Local mobility ................................................. 22
Local mobility management ...................................... 23 Local mobility management ...................................... 23
Location updating .............................................. 20 Location updating .............................................. 20
Loop-free ....................................................... 6 Loop-free ....................................................... 6
MAC ............................................................. 6
MBB ............................................................ 17
MH ............................................................. 11
MN ............................................................. 11
MNN ............................................................ 12
MPR ............................................................. 7
MR ............................................................. 11
Macro diversity ................................................ 19 Macro diversity ................................................ 19
Macro mobility ................................................. 22 Macro mobility ................................................. 22
Make-before-break (MBB) ........................................ 17 Make-before-break .............................................. 17
Medium Access Protocol (MAC) .................................... 6 Medium Access Protocol .......................................... 6
Micro diversity ................................................ 18 Micro diversity ................................................ 18
Micro mobility ................................................. 23 Micro mobility ................................................. 23
Mobile Host (MH) ............................................... 11 Mobile Host .................................................... 11
Mobile Network Node (MNN) ...................................... 12 Mobile Network Node ............................................ 12
Mobile Node (MN) ............................................... 11 Mobile Node .................................................... 11
Mobile Router (MR) ............................................. 11 Mobile Router .................................................. 11
Mobile network ................................................. 11 Mobile network ................................................. 11
Mobile network prefix ........................................... 6 Mobile network prefix ........................................... 6
Mobile-assisted handover ....................................... 16 Mobile-assisted handover ....................................... 16
Mobile-controlled handover ..................................... 16 Mobile-controlled handover ..................................... 15
Mobile-initiated handover ...................................... 15 Mobile-initiated handover ...................................... 15
Mobility factor ................................................. 6 Mobility factor ................................................. 6
Mobility security association .................................. 24 Mobility security association .................................. 24
Multipoint relay (MPR) .......................................... 6 Multipoint relay ................................................ 7
Neighbor ........................................................ 6 NAR ............................................................ 13
Neighborhood .................................................... 6 Neighbor ........................................................ 7
Neighborhood .................................................... 7
Network mobility support ....................................... 22 Network mobility support ....................................... 22
Network-assisted handover ...................................... 16 Network-assisted handover ...................................... 16
Network-controlled handover .................................... 16 Network-controlled handover .................................... 15
Network-initiated handover ..................................... 15 Network-initiated handover ..................................... 15
New Access Router (NAR) ........................................ 13 New Access Router .............................................. 13
Next hop ........................................................ 7 Next hop ........................................................ 7
Old Access Router (OAR) ........................................ 13 PAR ............................................................ 13
Paging ......................................................... 20 Paging ......................................................... 20
Paging area .................................................... 20 Paging area .................................................... 20
Paging area registrations ...................................... 20 Paging area registrations ...................................... 20
Paging channel ................................................. 20 Paging channel ................................................. 20
Pathloss ....................................................... 18 Pathloss ....................................................... 18
Pathloss matrix ................................................ 24 Pathloss matrix ................................................ 24
Payload ......................................................... 7 Payload ......................................................... 7
Personal mobility support ...................................... 22
Planned handover ............................................... 16 Planned handover ............................................... 16
Prefix .......................................................... 7 Prefix .......................................................... 7
Previous Access Router (PAR) ................................... 13 Previous Access Router ......................................... 13
Pull handover .................................................. 16
Push handover .................................................. 16
Radio Cell ..................................................... 12 Radio Cell ..................................................... 12
Registration key ............................................... 24 Registration key ............................................... 24
Roaming ........................................................ 13 Roaming ........................................................ 13
Route activation ................................................ 7 Route activation ................................................ 8
Route entry ..................................................... 7 Route entry ..................................................... 7
Route establishment ............................................. 7 Route establishment ............................................. 7
Route table ..................................................... 7 Route table ..................................................... 7
Routing proxy ................................................... 7 Routing proxy ................................................... 8
Routing-related service ........................................ 21 Routing-related service ........................................ 21
SAR ............................................................ 13
SPI ............................................................ 25
Scenario ....................................................... 24 Scenario ....................................................... 24
Seamless handover .............................................. 17 Seamless handover .............................................. 17
Security Parameter Index (SPI) ................................. 25 Security Parameter Index ....................................... 25
Security context ............................................... 25 Security context ............................................... 24
Serving Access Router (SAR) .................................... 13 Serving Access Router .......................................... 13
Signal strength ................................................. 7 Shannon's Law ................................................... 8
Signal strength ................................................. 8
Smooth handover ................................................ 17 Smooth handover ................................................ 17
Source route .................................................... 8 Source route .................................................... 8
Spatial re-use .................................................. 8 Spatial re-use .................................................. 8
Stale challenge ................................................ 25
Subnet .......................................................... 8 Subnet .......................................................... 8
System-wide broadcast ........................................... 8 System-wide broadcast ........................................... 8
Target AR (TAR) ................................................ 21 TAR ............................................................ 21
Target AR ...................................................... 21
Throughput ..................................................... 17 Throughput ..................................................... 17
Time-slotted dormant mode ...................................... 19 Time-slotted dormant mode ...................................... 19
Topology ........................................................ 8 Topology ........................................................ 9
Traffic channel ................................................ 20 Traffic channel ................................................ 20
Triggered update ................................................ 8 Triggered update ................................................ 9
Unassisted handover ............................................ 16 Unassisted handover ............................................ 16
Unknown challenge .............................................. 25
Unplanned handover ............................................. 16 Unplanned handover ............................................. 16
Unused challenge ............................................... 25
Vertical Handover .............................................. 15 Vertical Handover .............................................. 15
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the copyright notice or references to the Internet Society or other the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of Internet organizations, except as needed for the purpose of
 End of changes. 

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