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Mobile IP, and Micro Mobility
Gihwan Cho
[email protected]
Chonbuk National University, DCS Lab
1
presented by ghcho
Presentation Outline

Our talk includes



Mobile IP, and Mobile IP in IPv6
micro mobility variants
HAWAII
Cellular IP
fast handoff
proactive, anchor handoff
hierarchical handoff
paging extension
as a conclusion
Chonbuk National University, DCS Lab
2
presented by ghcho
Mobile IP

Now, let’s talk about



Mobile IP, and Mobile IP in IPv6
micro mobility variants
HAWAII
Cellular IP
fast handoff
proactive, anchor handoff
hierarchical handoff
paging extension
as a conclusion
Chonbuk National University, DCS Lab
3
presented by ghcho
Why Mobile IP ? (I)

Background





Internet explosion
increasing the mobile workforce, and mobile users
increased reliance on networked computing
prevailing the portable devices, technologies
IPv4 routing considerations




two level hierarchical address structure (network id, host id)
longest prefix (network id) matching based static routing
host id based routing may produce the scalability problem
if a host moves around, the network id should be changed!
then, the routing scheme to the MH may not applied!!
clearly, a corresponding host does not know (need not – by
network layering concept) the moving host’s current network
id
Chonbuk National University, DCS Lab
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presented by ghcho
Why Mobile IP ? (II)

So, which layer should take charge of host mobility?




applications, transport? IP? NI?
sure, IP could give to higher level protocols the abstraction that the
network address remains unchanged, therefore Mobile IP
Mobile IP allows users of portable computers to move form
one place to another and yet maintain transparent network
access through the wireless link
Initially, it does not assumed in design phase, for the host
mobility nature, so much appropriated to macro mobility

however, in the practical point of view, most moving entities have
some degree of moving pattern, that is micro mobility family
Chonbuk National University, DCS Lab
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presented by ghcho
Protocol Overview (I) [1][2]

Three steps with the protocol



agent discovery: MAs may advertise their availability for they
provide service, or a newly arrived MH may send a solicitation to
learn if any prospective agents are present
ICMP router discovery [3]
registration: when an MH is away from home, it registers its careof address with its HA
UDP control messages [1] [2]
tunneling: datagrams sent to an MH is away from home must be
tunneled to hide its home address from intervening routers
encapsulation protocol [4][5]
Chonbuk National University, DCS Lab
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presented by ghcho
Protocol Overview (II)
Mobile Node
FA (FA)
HA (HA)
Correspondent
Node
Agent Solicitation
Agent Advertisement
agent discovery
Registration Request
Registration Request
Registration Reply
registration
Registration Reply
Data sent
Data received
tunneling
Chonbuk National University, DCS Lab
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presented by ghcho
Protocol Overview (III)
Correspondent
Node
HA
location
registration
data paths (before
registration)
data paths
(sent from MN)
Internet
tunnel
Chonbuk National University, DCS Lab
Mobile Node
packet
tunneling
data paths (after
registration)
FA
agent
discovery
host moving
Mobile Node
FA
8
presented by ghcho
Triangle Routing on Mobile IP
Internet
Host
Home-based
Location
Home
Agent
Reply Path
Tunneling
FA
MH k
Host Moving

Triangle routing is undesirable :


Increased network utilization (sensitivity to network partition)
Irregularity of performance variance
Chonbuk National University, DCS Lab
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presented by ghcho
Mobile IPv4 – revised (I)



Specification that the SPI of the MN-HA authentication
extension is to be used as part of the data over which
the authentication algorithm must be computed
Specification that FA may send advertisements at a rate
faster than once per second, but must be chosen so that
the advertisements do not burden the capacity of the
local link
Specification that FAs should support reverse tunneling,
and HAs must support decapsulation of reverse tunnels
Chonbuk National University, DCS Lab
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presented by ghcho
Mobile IPv4 – revised (II)



Changed the pre-configuration requirements for the MHs
to reflect its capability
An FA is not required to discard Registration Replies that
have a home address field that does not match any
pending Registration Request
Allowed registration to be authenticated by use of a
security association between the MH and a suitable
authentication entity acceptable to the HA

noted that HMAC-MD5 should be considered for use in place of
the “prefix+suffix” mode of MD5 as originally mandated in RFC
2002
Chonbuk National University, DCS Lab
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presented by ghcho
Mobile IPv4 – revised (III)

Clarification that an MA should only put its own
addresses into the initial list of routers in the mobility
advertisement


RFC 2002 suggests that an MA might advertise other default
routers
Specification that an MH must ignore reserved bits in
Agent Advertisement, as opposed to discarding such
advertisements

in this way, new bits can be defined later, without affecting the
ability for MHs to use the advertisements even when the newly
defined bits are not understood
Chonbuk National University, DCS Lab
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presented by ghcho
Mobile IPv4 – revised (IV)

Specification that the FA checks to make sure that the
indicated HA does not belong to any of its network
interface before relaying a Registration Request



if the check fails, and the FA is not the MH’s HA, then the FA
rejects the request with code 136
Specification that, while they are away from the home
network, MHs must not broadcast ARP packets to find
the MAC address of another internet node
Specification that an FA must not use broadcast ARP for
an MHs MAC address on a foreign network

it may obtain the MAC address by copying the information from
an Agent Solicitation or a Reg. Request transmitted from an MH
Chonbuk National University, DCS Lab
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presented by ghcho
Mobile IPv4 – revised (V)




Specification that an FA’s ARP cache for the MH’s IP
address must not be allowed to expire before the MH’s
visitor list entry expires
Clarified that an HA must not make any changes to the
way it performs proxy ARP after it rejects an invalid
deregistration request
Specification that multi-homed HA must use the
registered care-of address as the source address in the
outer IP header of the encapsulated datagram
Inserted “T” bit into its proper place in the Registration
Request message format
Chonbuk National University, DCS Lab
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presented by ghcho
Micro Mobility – HAWAII [6]

Now, let’s talk about



Mobile IP, and Mobile IP in IPv6
micro mobility variants
HAWAII
Cellular IP
fast handoff
proactive, anchor handoff
hierarchical handoff
paging extension
as a conclusion
Chonbuk National University, DCS Lab
15
presented by ghcho
IP Micro Mobility – HAWAII (I)

Overview

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


Handoff Aware Wireless Access Internet Infrastructure (by Lucent)
domain-based approach for supporting mobility
approach : most user mobility is local to a domain
specialized path setup schemes
host-based routing entry
Characteristics

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reduce mobility related disruption to user application
reduce the number of mobility related updated
simplify QoS support
improved reliability with soft-state transition
provide macro mobility in conjunction with Mobile IP
include the paging concept
Chonbuk National University, DCS Lab
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presented by ghcho
IP Micro Mobility – HAWAII (II)

Mobility support for inter-HAWAII domain : Mobile IP


so, macro mobility
HAWAII protocol defines the mobility support for intraHAWAII domain, so, micro mobility




each router maintains a routing entry per moving host
then, change only the corresponding entry on host moving
as a result, in a domain, the overhead of top most router can be
distributed into the lower-level routers
host handoff may support by
a forwarding scheme
a non forwarding scheme
Chonbuk National University, DCS Lab
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presented by ghcho
IP Micro Mobility – HAWAII (III)


Use path setup message to establish and update hostbased routing entries in selective routers in the domain
-> where, how, and which routers are updates?
Forwarding scheme : optimized for TDMA network


Non forwarding scheme : optimized for CDMA network



update the forwarding entry from old BS to new BS
update the forwarding entry from new BS to old BS
Other routers has no MH’s current location
Forwarding entry must be updated in periodical, so soft
state update, to prevent its out-of-state situation

refresh message
Chonbuk National University, DCS Lab
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presented by ghcho
IP Micro Mobility – HAWAII (IV)
Chonbuk National University, DCS Lab
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presented by ghcho
IP Micro Mobility – HAWAII (V)
Chonbuk National University, DCS Lab
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presented by ghcho
Forwarding Path Setup
Chonbuk National University, DCS Lab
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presented by ghcho
Non-Forwarding Path Setup
Chonbuk National University, DCS Lab
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presented by ghcho
Paging

Network determines the exact location by paging to
deliver packets

“idle” MHs update the network less frequently than “active”MHs

network has only approximate location information for idle MHs
Chonbuk National University, DCS Lab
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presented by ghcho
Hierarchy using Domain
Chonbuk National University, DCS Lab
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presented by ghcho
Paging Design Goals

Efficiency


Scalability


push paging initiation closer to the base station
Reliability

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limit updates from the MH when idle to conserve battery power
allow paging initiation to occur at any router/base station (no
single points of failure)
Flexibility

allow for fixed, hierarchical, or user-defined paging areas
Chonbuk National University, DCS Lab
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presented by ghcho
Paging Support … HAWAII (I)
Chonbuk National University, DCS Lab
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presented by ghcho
Paging Support … HAWAII (II)
Chonbuk National University, DCS Lab
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presented by ghcho
Router Operation
Chonbuk National University, DCS Lab
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presented by ghcho
Paging with Mobile-IP

When using FAs

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
group set of FAs into multicast group
previous FA initiates paging
impact of previous FA failure
When operating without FAs

paging initiated from HA
globally visible multicast address or separate unicasts necessary

scalability is an issue

Chonbuk National University, DCS Lab
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presented by ghcho
Micro Mobility – Cellular IP [7]

Now, let’s talk about



Mobile IP, and Mobile IP in IPv6
micro mobility variants
HAWAII
Cellular IP
fast handoff
proactive, anchor handoff
hierarchical handoff
paging extension
as a conclusion
Chonbuk National University, DCS Lab
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presented by ghcho
Cellular IP (CIP)

Cellular IP is intended to:





specify a protocol that allows routing IP datagrams to an MH
provide local mobility and handoff support
minimize packet losses with the location update delay
interwork with Mobile IP to provide wide area mobility support
Design principles



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location information is stored in distributed data bases
location information referring to an MH is created and updated
by regular IP datagrams
location information is stored as soft state
location management strategy is separated between the idle MH
and the active MH
Chonbuk National University, DCS Lab
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presented by ghcho
Protocol Requirement

Protocol requirement






a host connected to a cellular IP network must be able to send
IP datagram to hosts outside the cellular IP network
datagrams arriving to a cellular IP network should be delivered
with high probability to the destination host
datagram delivery in a cellular IP network should be take
placed without leaving the cellular IP network
an MH migrating between cellular IP network must be to use
Mobile IP for wide area mobility, that is, a host in a cellular IP
network has a home address with a care-of-address
hosts inside a cellular IP network are identified by IP
addresses, but these have no location significance
hosts outside the cellular IP network must not need any
updating or enhancement, i.e. they must remain unware of the
host’s current location inside the cellular IP network
Chonbuk National University, DCS Lab
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presented by ghcho
Hierarchical Mobility Management (I)

Global mobility with Mobile IP
Chonbuk National University, DCS Lab
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presented by ghcho
Hierarchical Mobility Management (II)

Local mobility with cellular IP


fast handoff within a mobile access network
less load in the global Internet
Chonbuk National University, DCS Lab
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presented by ghcho
Wireless Overlay Networks
Chonbuk National University, DCS Lab
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presented by ghcho
Mobile Access Network
Chonbuk National University, DCS Lab
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presented by ghcho
Protocol Overview (I)



Base stations periodically emit beacon signals to be
locate the nearest base station by MHs
All IP packets transmitted by an MH are routed from the
BS to the GW by hop-by-hop shortest path routing
regardless of the destination address
Cellular IP nodes maintain routing cache


packets transmitted by the MH create and update entries in each
node's cache, thus an cache entry maps the MH’s IP address to
the interface through which the packet entered the node
The chain of cached mappings referring to a single MH
constitutes a reverse path for downlink packets
addressed to the same MH
Chonbuk National University, DCS Lab
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presented by ghcho
Protocol Overview (II)


To prevent its mappings from timing out, an MH can
periodically transmit control packets


as the MH migrates, the chain always points to its current
location because its uplink packets create new mappings and old
mappings are automatically cleared after a soft state timeout
control packets are regular IP packets with empty payloads
MHs that are not actively transmitting or receiving data
but want to be reachable for incoming packets, let their
routing cache mappings time out but maintain paging
cache mappings


IP packets addressed to these MHs will be routed by paging
caches
paging caches have a longer timeout value than routing caches
and are not necessarily maintained in every Node
Chonbuk National University, DCS Lab
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presented by ghcho
Mobile IP vs. Cellular IP

Global mobility support vs. local fast smooth handoff
Chonbuk National University, DCS Lab
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presented by ghcho
Uplink Path : Shortest Path
Chonbuk National University, DCS Lab
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presented by ghcho
Uplink Packets Create Location
Information
Chonbuk National University, DCS Lab
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presented by ghcho
Downlink Packets (I)

Mobile IP’s centralized location management
Chonbuk National University, DCS Lab
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presented by ghcho
Downlink Packets (II)

Cellular IP’s distributed location database
Chonbuk National University, DCS Lab
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presented by ghcho
Control Packet in Uplink
if no Data or a Move Detected
Chonbuk National University, DCS Lab
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presented by ghcho
Handoff is Automatic
Chonbuk National University, DCS Lab
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presented by ghcho
Idle Host Location Management
Tradeoff
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presented by ghcho
Location Management of Idle Hosts

Paging setup



paging cache maintains in just some selected nodes
broadcast if a node has not paging (and routing) cache
paging cache is updated with a control packet, with longer
timeout and less frequently
Chonbuk National University, DCS Lab
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presented by ghcho
Paging Cache Update with a move
Chonbuk National University, DCS Lab
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presented by ghcho
Paging Route with Paging Cache
Chonbuk National University, DCS Lab
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presented by ghcho
Cellular IP MH

Each MH has two states in legal, active and idle



when the state changed from idle to active, it sends a route
update packet to the gateway
if an MH is in the active state
the MH has to send a route update packet whenever it
changes its current base station
if an MH is in the idle state
the MH has to send a paging update packet whenever it
enters a new paging area or it meets a predefined period
Chonbuk National University, DCS Lab
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presented by ghcho
Extensions to Cellular IP

During handoffs between base stations within the same
paging area, idle MHs may remain silent, as paging is
performed within the entire paging area
Chonbuk National University, DCS Lab
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presented by ghcho
Cellular IP Considerations

In Summary





Advantages






distributed location management
location information established by uplink IP packet
soft state management
location management of idle hosts is separated from active hosts
simple, self-sufficient nodes
simple mobility management : just send control packet if no data
no control messaging at handoff
soft states give built-in fault tolerance
handoff or faults do not differ from normal operation
Any problems?

Load from control packets ...
Chonbuk National University, DCS Lab
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presented by ghcho
Micro Mobility – Fast Handoff [8]

Now, let’s talk about



Mobile IP, and Mobile IP in IPv6
micro mobility variants
HAWAII
Cellular IP
fast handoff
proactive, anchor handoff
hierarchical handoff
paging extension
as a conclusion
Chonbuk National University, DCS Lab
53
presented by ghcho
Fast handoffs overviews (I)


Fast handoffs are required in mobile IPv4 in order to limit
the period of service disruption experienced by an MN
It can be usually achieved



by anticipating the movement of MN
by utilizing simultaneous bindings in order to send multiple
copies of the traffic to potential MN movement locations
Simply, it is achieved by bicasting traffic to the previous
FA and new FA while the MN moving between them

both a flat and a hierarchical mobile IPv4 model are considered
Chonbuk National University, DCS Lab
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presented by ghcho
Fast handoffs overviews (II)

The anticipation of the MN’s movement is achieved


Fast handoffs coupled to the layer 2



by tight coupling with layer 2 functionality which is dependent on
the type of access technology used
limit the total handoff delay to the time needed to perform the
layer 2 handoff
allow MN to initiate fast handoff through the previous FA without
having direct access to the new FA
Fast handoffs may be applied to Mobile IP

by performing registrations with the HA using simultaneous
bindings
Chonbuk National University, DCS Lab
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presented by ghcho
Simultaneous bindings (I)

Simultaneous bindings in MIPv4




may be achieved by setting the ‘S’ bit in the Mobile IP
Registration Request message sent by the MN
cause the receiving agents(HA, GFA, regional FA, previous FA)
to add a new binding for the MN without removing any which are
existing
are likely to be useful when an MN using at least one wireless
network interface moves within wireless transmission range of
more than one FA
cause the HA to send multiple copies of data packets towards
multiple FAs which may be in the same region or domain
Chonbuk National University, DCS Lab
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presented by ghcho
Simultaneous bindings (II)
HA
CN
Internet
old FA
: bicasting
MN
new FA
Chonbuk National University, DCS Lab
MN
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presented by ghcho
Flat and Hierarchical MIPv4 model

A flat and a hierarchical (with GFA) MIPv4 model
Internet
HA
Internet
HA
GFA
CN
FA3
FA1
FA2
FA2
AP2
FA1
AP1
AP2
MN
Chonbuk National University, DCS Lab
CN
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AP3
AP1
MN
presented by ghcho
Visited
Domain
Flat Mobile IPv4 (FMIPv4) (I)

The wireless layer 2 technology allows the MN to be
connected to multiple wireless access points
simultaneously



the MN may solicit advertisements from FAs before completing
handoffs
The layer 2 handoff does not finished until the MN’s
registration with the new FA which produces a
simultaneous binding at the HA
Fast handoff requires the MN


to receive new agent advertisements through the old AP
to perform a registration with the new FA through the old AP
Chonbuk National University, DCS Lab
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presented by ghcho
FMIPv4 (II)

Initiating fast handoffs through the old FA



inter-FA solicitation
piggy backing advertisements on layer 2 messaging
Inter-FA solicitation


this solution assumes that the FA with which the MN is currently
registered is aware of the IP address of the new FA
once the current FA is aware of the address of the new FA
the current FA will send the new FA an agent solicitation
message
the new FA will reply to the current FA by sending it an agent
advertisement, then the current FA will send the agent
advertisement to the MN
MN will send a registration request to the new FA through old
AP served by the current FA
Chonbuk National University, DCS Lab
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presented by ghcho
FMIPv4 (III)

Inter-FA solicitation :
4. Agent
advertisement
MN
3. Agent
advertisement
AP
current FA
1. Agent
Solicitation
2. Agent
advertisement
5. Registration
Request
6. Registration
Request
7. Registration
Request
new FA
Chonbuk National University, DCS Lab
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presented by ghcho
FMIPv4 (III)

Inter-FA solicitation :
GFA
Internet
HA
8. Registration
request
1. Agent solicitation
old FA
2. Agent advertisement
new FA
6. Registration request
3. Agent
advertisement
old AP
7. Registration
request
5. Registration
request
new AP
4. Agent
advertisement
Chonbuk National University, DCS Lab
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MN
presented by ghcho
FMIPv4 (IV)

Piggy-backing advertisements on layer 2 messaging




it is assumed that when an layer 2 handoff is initiated, old AP and
new AP perform layer 2 messaging procedures to negotiate
handoff
since the MN is not attached to new AP yet
new FA is unaware of the IP address of the MN and cannot
send an advertisement to it
it is necessary for the layer 2 procedures to interwork with MIP
once an layer 2 handoff is initiated, such that old AP and new AP
are in communication, it is possible for new AP to solicit an
advertisement from new FA and transfer it to old AP
when the advertisement is received by the MN, the MN can
perform a registration directed to new FA even though the MN has
no data-connection to new AP yet
Chonbuk National University, DCS Lab
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presented by ghcho
FMIPv4 (V)

Piggy-backing advertisements on layer 2 messaging :
GFA
Internet
HA
7. Request
registration
old FA
2. Reply advertisement
3. Reply
advertisement
old AP
6. Request registration
5. Request
registration
new FA
1. Request
advertisement
new AP
4. Reply
advertisement
MN
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presented by ghcho
Hierarchical Mobile IPv4 (HMIPv4) (I)

HMIPv4 allows a MN to perform registrations locally with
a Gateway FA(GFA) in order to reduce the number of
signaling messages to the home network




it achieves a reduction in the signaling delay when a MN moves
between FAs within a domain
MN may be attached directly to any FA within the hierarchy and
moves between FAs
there may be multiple paths between MN and GFA
Triangle routing between nodes within the hierarchical
domain is eliminated by direct routing through regional
FAs or reduced by routing through the GFA
Chonbuk National University, DCS Lab
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presented by ghcho
HMIPv4 (II)

HMIPv4 supplements with the following for Fat MIPv4




limitation of triangle routing for communication between hosts
within the administrative domain
fast handoffs within the administrative domain
considerations on regional deregistration
Regional tunnel management allows Regional
Registrations within an administrative domain in order to
avoid always having to perform registrations through HA


the GAF’s address always appears to the HA as the MN’s care of
address
some of the HA’s functionality is performed locally in the GFA
Chonbuk National University, DCS Lab
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presented by ghcho
Regional Registration (I) : HMIPv4

When MN first arrives at a visited domain, it performs a
registration with its home network
MN
Regional FA
1. Registration
Request
6. Registration
Reply
2. Registration
Request
GFA
5. Registration
Reply
3. Registration
Request
4. Registration
Reply
HA
Chonbuk National University, DCS Lab
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presented by ghcho
Regional Registration (II) : HMIPv4

The Signaling message flow for RR
MN
1. RR Request
4. RR Reply
2. RR Request
3. RR Reply
New FA
GFA
Chonbuk National University, DCS Lab
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presented by ghcho
Regional Registration (III) : HMIPv4

FA announces its presence via an agent advertisement
message



an agent advertisement message includes the corresponding
addresses in order between its own address(first) and the GFA
address(last) in the Mobility Agent Advertisement (MAA)
extension
Once the home agent has registered the GFA address
as the care of address of MN, MN may perform RR
When MN receives an agent advertisement from FA, MN
can perform a RR with this FA and GFA
Chonbuk National University, DCS Lab
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presented by ghcho
Fast Handoffs (I) : HMIPv4

When MN receives an agent advertisement with a MAA
extension, MN must



MN may add a hierarchical FA extension to registration
requests in order to identify the exact FA path


be eager to perform new bindings
be lazy in releasing existing bindings
if MN has at least one existing binding with a FA, additional
simultaneous RR performed
There are two ways that MN choices the appropriate HA
address in the RR Request


MAA extension advertises FA and GFA address only
MAA extension advertises complete order of FAs in the branch
Chonbuk National University, DCS Lab
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presented by ghcho
Fast Handoffs(II) : HMIPv4

MAA extension advertises FA and GFA address only





it is assumed that there is always a single path from the MN to
the GFA
MN always performs RR using the GFA address as HA address
and the advertising FA as care of address
as the RR request is relayed towards the GFA, each FA
receiving it will check whether it has an existing binding with the
MN and whether RR has the ‘S’ bit set to request for
simultaneous bindings
if this is true and the RR is validated by the GFA, FAs activate
the simultaneous binding upon receiving the RR Replay from the
GFA
it is not necessary to advertise to the MN all of the FA addresses
in hierarchical branch
Chonbuk National University, DCS Lab
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presented by ghcho
Fast Handoffs(III) : HMIPv4

MAA extension advertises FA and GFA address only
MN
New FA
1. Agent
2. RR Request
Advertisement
(MAA extension)
5. RR Reply
4. RR Reply
3. RR Request
GFA
Chonbuk National University, DCS Lab
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presented by ghcho
Fast Handoffs(IV) : HMIPv4

MAA extension advertises complete order of FAs in the
branch





where multiple regional FA levels, and multiple paths from the
MN to the GFA are present, it may be necessary for the MN to
identify the common route FA using the complete list of FAs in
the hierarchical branch
MN must cache MAA extensions for its active bindings
when MN receives an advertisement from new FA which has a
different MAA extension, MN will be eager to perform a new
binding
MN compares the IP address in the new MAA extension with the
ones it has cached for its active binding
a regional FA receiving RR request with it’s own address as HA
address may return a RR reply to the MN
Chonbuk National University, DCS Lab
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presented by ghcho
Fast Handoffs(V) : HMIPv4

MAA extension advertises complete order of FAs in the
branch
MN
New FA
1. Agent
2. RR Request
Advertisement
(MAA extension)
3. RR Request
7. RR Reply
6. RR Reply
4. RR Request
5. RR Reply
GFA
Chonbuk National University, DCS Lab
74
presented by ghcho
Micro Mobility - Proactive, Anchor
Handoff [9][10]

Now, let’s talk about



Mobile IP, and Mobile IP in IPv6
micro mobility variants
HAWAII
Cellular IP
fast handoff
proactive, anchor handoff
hierarchical handoff
paging extension
as a conclusion
Chonbuk National University, DCS Lab
75
presented by ghcho
Proactive Handoff (I) [10]


Proactive handoff aims to limit handoff delay to the time
needed to perform a L2 handoff
It is based on predicting the movement of MHs
anticipating new points of attachment



first, it completes L2 handoff then starts to forward data to the
MH
it allows L3 registration to proceed
finally, handoff control is driven by the network as opposed to
MH
Chonbuk National University, DCS Lab
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presented by ghcho
Proactive Handoff (II)

Movement Detection



when an FA is aware that an handoff is occurring at the linklayer, a trigger is sent to the mobile IP protocol stack
a source trigger is one that is obtained by the old FA once the
link layer detects that the MH is departing its coverage area
a target trigger is one that is obtained by the new FA once the
link layer detects that the MH is arriving in its coverage area
Chonbuk National University, DCS Lab
77
presented by ghcho
Proactive Handoff (III)

Source trigger proactive handoff
HA
Internet
GFA
4. Registration Reply
Move detect
oFA
3. Registration Request
1. Handoff Request
nFA
2. Handoff Reply
MN
MN
Chonbuk National University, DCS Lab
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presented by ghcho
Proactive Handoff (IV)

Target trigger proactive handoff
HA
Internet
GFA
4. Registration Reply
oFA
3. Registration Request
1. Handoff Request
Move detect
nFA
2. Handoff Reply
MN
MN
Chonbuk National University, DCS Lab
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presented by ghcho
Proactive Handoff (IV)

Functional components
FAAA
HAAA
DHCPv6
MN
DHCPv6
SMM
HA1
HA2
HMM
HAn
HA1
HA2
HAn
SMM : Serving Mobility Manager
HMM : Home Mobility Manager
Chonbuk National University, DCS Lab
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presented by ghcho
Proactive Handoff (V)

Proactive intradomain handoff
BU : Binding Update
BA : Binding Ack.
time
Mobile Node
nSMM
DHCPv6
oSMM
System
Handoff
Request
DHCPv6
Request
Handoff
And
Context
Trans
Request
DHCP
v6Res
Handoff
And
Context
Trans
Response
BU
System
Handoff
Response
BU
BA
BA
HAn
HMM
BU
BA
HAm
BU
CNn
Chonbuk National University, DCS Lab
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presented by ghcho
BA
Proactive Handoff (VI)
1. when the MN detects that it is moving to another new subnetwork that belongs to the same domain of the current subnetwork , it sends a System Handoff Request to the current SMM
(oSMM)
2. the oSMM sends an handoff and Context Transfer Request to
the new SMM (nSMM)
3. the nSMM allocates a new COA to the MN and returns back a
handoff and Context Transfer Response to the oSMM
4. the oSMM allocates an HA for the MN to bicast the data destined
to the MN to both old and new COA. The oSMM sends a System
Handoff Response to the MN confirming the completion of the
handoff process
5. when the MN receives the System Handoff Response from the
oSMM and establishes a L2 connectivity with the new
Chonbuk National University, DCS Lab
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presented by ghcho
Proactive Handoff (VII)

Proactive interdomain handoff
BU : Binding Update
BA : Binding Ack.
time
Mobile Node
nSMM
DHCPv6
System
Handoff
Request
DHCPv6
Req
Reg Res
DHCP
v6Res.
AAan HAndoff And
Context Trans Res
nFAAA
oFAAA
RegReq
AAan HAndoff
And Context
Trans Request
System
Handoff
Res
AAA Reg
Req
BU
AAA Reg
Res
oSMM
BU
HAk
BA
HAAA
RegReq
RegRes
HMM
HA
Chonbuk National University, DCS Lab
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presented by ghcho
BA
Proactive Handoff (VIII)
1. when the MN detects that it is moving to a new sub-network that
belongs to a different administrative domain, it sends a System
Handoff request to the old SMM(oSMM)
2. the oSMM sends a AAan HAndoff and Context Transfer Request
to the new SMM(nSMM) via the AAA infrastructure
3. the nSMM allocates new COA to the MN and returns back a AAA
infrastructure
4. the oSMM allocates an HA for the MN to bicast the data destined
to the MN to both old and new COA. The oSMM sends a System
Handoff Response to the MN confirming the completion of the
handoff process
5. when the MN receives the System Handoff Response from the
oSMM and establishes a L2 connectivity with the new subnetwork it sends a Registration Request to the nSMM
Chonbuk National University, DCS Lab
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presented by ghcho
Proactive Handoff (IX)
6. the nSMM constructs a AAA Registration Request and sends it to
the HAAA via the FAA
7. when the HAAA receives the AAA Registration Request, it
attempts to authenticate the MN. If the MN’s authentication and
authorization are affirmative, the request is forwarded to the
HMM for further processing
8. the HMM updates the user state information. It then constructs a
Registration Response message and subsequently forwards to
the MN via the HAAA and the FAAA
9. once the MN receives a successful Registration Response from
the network, it proceeds with the regular MIPv6 registration
Chonbuk National University, DCS Lab
85
presented by ghcho
Fast vs. Proactive (I)

Proactive
HA
Internet
1. L2 handoff is completed
2. then, L3 registration is started
GFA
2
oFA
nFA
Layer 3
oAP
1
nAP
Layer 2
MN
MN
Chonbuk National University, DCS Lab
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presented by ghcho
Fast vs. Proactive (I)

Fast
HA
1. L3 registration is completed,
rather than L2 handoff
2. Bi-Casting
3. it is not sure whether L2
handoff has completed
Internet
GFA
2
oFA
nFA
oAP
nAP
1
3. L2 handoff
MN
MN
Chonbuk National University, DCS Lab
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presented by ghcho
Layer 3
Layer 2
Anchor Handoff (I) [11]





Anchor handoff proposes a number of enhancements to
ease local registration and global indirect registration
An MH authenticates with its HA during global registration
and establishes a secure tunnel between the HA and FA
The FA then acts as anchor FA for future registrations
So, only a local registration is necessary after handoff
This rule holds as long as the MH moves within the same
domain between the visiting FA and the anchor FA
Chonbuk National University, DCS Lab
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presented by ghcho
Anchor Handoff (II)

Local registration
HA
Home
Network
Internet
Tunnel
Visited
Network
FA2
FA1
MN
MN
Chonbuk National University, DCS Lab
Anchor
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presented by ghcho
Anchor Handoff (III)

Global indirect registration
HA
Home
Network
Internet
Tunnel
Visited
Network
FA2
FA1
MN
MN
Chonbuk National University, DCS Lab
Anchor
90
presented by ghcho
Micro Mobility – Hierarchical Handoff [12]

Now, let’s talk about



Mobile IP, and Mobile IP in IPv6
micro mobility variants
HAWAII
Cellular IP
fast handoff
proactive, anchor handoff
hierarchical handoff
paging extension
as a conclusion
Chonbuk National University, DCS Lab
91
presented by ghcho
Hierarchical Mobile IP (I) [13]

Background



in Mobile IP
a mobile node registers with its HA each time it changes
care-of address
if the distance between the visited network and the home
network of the mobile node is large the signaling delay for
these registration may be long
it is solution for performing registrations locally in the visited
domain : regional registrations
by registering locally the signaling delay is reduced, and this may
improve the performance of handover
Chonbuk National University, DCS Lab
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presented by ghcho
Hierarchical Mobile IP (II)

Processing


when an MN first arrives at a visited domain, it performs home
registration
during a home registration the HA registers the address of
GFA(gateway FA) as the care-of address of the MH
this care-of address will not change when the MH changes
FA under the same GFA
when changing GFA, MN must perform a home registration
Chonbuk National University, DCS Lab
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presented by ghcho
Hierarchical Mobile IP (III)

HMIP employs a hierarchy of FAs to locally handle
Mobile IP registration




MH send mobile IP registration messages to update their
respective location information
registration messages establish tunnels between neighboring
FAs along the path from the MH to a GFA
the use of tunnels makes it possible to employ the protocol in an
IP network that carries non-mobile traffic as well
typically one level of hierarchy is considered where all FAs are
connected to the GFA
in this case direct tunnels connect the GFA to FAs that are
located at access points
Chonbuk National University, DCS Lab
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presented by ghcho
Hierarchical Mobile IP (IV)
HA
Correspondent
Node
Internet
GFA
FA
IP registration message
FA
Tunnel
Route from CN to MN after
regional registration
Chonbuk National University, DCS Lab
MN
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presented by ghcho
Hierarchical Mobile IPv6 (I) [14] [15]

Background



in Mobile IPv6 there are no FAs, but there is still need to provide
a central point to assist with MIP handoffs
similar to MIPv4, Mobile IPv6 can benefit from reduce mobility
signaling with external networks by employing local hierarchical
structure
For this reason a new Mobile IPv6 node, called Mobility
Server(MS), is used
Chonbuk National University, DCS Lab
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presented by ghcho
Hierarchical Mobile IPv6 (II)

Features




as the existing hierarchical Mobile IP scheme it uses anchor
points called mobility servers(MS) to deploy two levels of
hierarchies (MS is called Mobility Anchor Point(MAP) in other
IETF draft)
it uses of new IPv6 functionalities such as a large address space
and neighbor discovery mechanisms to support flexible, scalable
and robust mobility management
supports two or more levels of hierarchy
the simplest implementation of HMIPv6 supports two levels
of hierarchy (e.g. micro-mobility protocol and Mobile IP)
each domain contains one or several MSs as the level of
hierarchy
Chonbuk National University, DCS Lab
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presented by ghcho
Hierarchical Mobile IPv6 (III)

Address allocation





if MH moves into new domain it gets two CoA
global CoA(GCoA) and local CoA(LCoA)
If it moves within a domain
it only needs to change its LCoA
The GCoA remains the same
MH register its GCoA with its HA and correspondent hosts
in contrast to HMIPv4 schemes, the GCoA is not the address of
the MS but an address belongs to the MS’s subnet
as a result, the MS can be changed dynamically without having
to change the GCoAs of the MHs currently roaming in the
domain
Chonbuk National University, DCS Lab
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presented by ghcho
Hierarchical Mobile IPv6 (IV)

Processing

packets addressed to the MH’s GCoA are routed to the domain
intercepted by the MS and encapsulated to the MH’s current
LCoA
Chonbuk National University, DCS Lab
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presented by ghcho
Hierarchical Mobile IPv6 (V)
HA
Correspondent
Node
Internet
Route before registration
MS
IPv6 router
IPv6
router
Tunnel
MN
Intercept the packets
Route from CN to MN after
regional registration
Chonbuk National University, DCS Lab
100
presented by ghcho
Micro Mobility – Paging Extension [16]

Now, let’s talk about



Mobile IP, and Mobile IP in IPv6
micro mobility variants
HAWAII
Cellular IP
fast handoff
proactive, anchor handoff
hierarchical handoff
paging extension
as a conclusion
Chonbuk National University, DCS Lab
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presented by ghcho
Paging Extensions for Mobile IP (I)

P-MIP


is designed to reduce signaling load in the core Internet and
power consumption of MHs
The state of MH


active mode : operate in exactly the same manner as in Mobile IP
when an MH changes its point of attachment, it registers with
a new FA
idle mode : register to HA after receiving paging request
in contrast, MH do not register when they move in a same
paging area
it is forced to register only when it moves to a new paging area
Chonbuk National University, DCS Lab
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presented by ghcho
Paging Extensions for Mobile IP (II)
1. HA forward data packets to registered FA(rFA)
2. rFA checks MH’s information on record
if it has, rFA checks that MH supports paging or not
if it supports, rFA checks the MH’s state
3. If MH is in active mode, rFA decapsulates and forwards packets to the MH
4. If MH is in idle mode, rFA sends a paging request message to its own access
network and other FAs in the paging area
5. When MH receives a paging request, it registers through the current FA to its
HA
6. After receiving a registration request MH sends a paging reply back to its rFA
through its current FA to inform the register FA of its current location
7. When rFA receives a paging reply, it forwards any buffered packets to the MH
Chonbuk National University, DCS Lab
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presented by ghcho
Paging Extensions for Mobile IP (III)
HA
Data packets
Paging request message
1
Internet
2
4
FA
rFA
3
FA
MN
MN
Paging area
MN
Chonbuk National University, DCS Lab
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presented by ghcho
Paging Extensions for Mobile IP (IV)
HA
Registration message
Paging reply message
Orphan data packets
Internet
6
7
FA
rFA
FA
MN
MN
5
Paging area
MN
Chonbuk National University, DCS Lab
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presented by ghcho
As a Conclusion : Micro Mobility (I)

Mobile IP WG is in the process of consolidating all
contributions with the idea of having one standard



its filtering strategy is to eliminate any proposals that did not
support tunneling and Mobile IP messaging
initially 4 proposals has been considered, then 2 proposals,
proactive and fast handoff were left in discussion
at a moment, the WG is in the process of discussing the pos and
cons of these 2 proposals
Chonbuk National University, DCS Lab
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presented by ghcho
As a Conclusion : Micro Mobility (II)

Similarities of the proactive handoff and fast handoff



aim to limit delay to the time needed to perform a L2 handoff
make use of predicting the movements of MHs to anticipate new
points of attachments
Differences of the proactive handoff and fast handoff


the former first completes L2 handoff, then starts to forward data to
the MH, and finally, allows L3 registration to proceed : handoff
control is driven by the network
the later anticipates the movements of an MH allowing the MH to
register with the new FA or GFA prior to L2 connectivity being
established : handoff is initiated by MH
Chonbuk National University, DCS Lab
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presented by ghcho
As a Conclusion : Micro Mobility (III)

Considerations




what is the minimal coupling between the L3 and L2 to facilitate
fast handoff?
is the predicting new access points in advance assumption
reasonable?
MH initiated or network initiated?
The process of consolidating these two proposals has
recently resulted in a single proposal for fast and low
latency handoff for Mobile IPv4, as well as Mobile IPv6
Chonbuk National University, DCS Lab
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presented by ghcho
Reference (I)
[1] C. Perkins, “IP Mobility Support,” IETF RFC 2002, Oct. 1996.
[2] C. Perkins, “IP Mobility Support for IPv4, revised,” IETF Draft, draft-ietfmobileip-rfc2002-bis-03.txt, Sep. 2000.
[3] S. Deering, “ICMP Router Discovery Messages,” IETF RFC 1256, Sep.
1991.
[4] C. Perkins, “IP Encapsulation within IP,” IETF RFC 2003, Oct. 1996.
[5] C. Perkins, “Minimal Encapsulation within IP,” IETF RFC 2004, Oct. 1996.
[6] R. Ramjee, et. al., “HAWAII : a domain-based approach for supporting
mobility in wide-area wireless networks,” Proc. IEEE International
Conference on Network Protocols, pp.283-292, 1999.
[7] A.Campbell, et. al., “Cellular IP,” IETF Draft, draft-ietf-mobileip-cellularip-00.txt, Dec.
1999.
[8] K. Malki, H. Soliman, “Fast Handoffs in Mobile IPv4,” IETF Draft, draft-elmalkimobileip-fast-handoffs-03.txt, Sep. 2000.
Chonbuk National University, DCS Lab
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presented by ghcho
Reference (II)
[9] G. Tsirtsis, “Fast handovers for Mobile IPv6,” IETF Draft, draft-ietf-mobileip-fastmipv6-01.txt, Apr. 2001
[10] P. Calhoun, et. al., “FA Assisted Hand-off,” IETF Draft, draft-calhoun-mobileipproactive-fa-01.txt, Jun.2000.
[11] G. Dommety, “Local and Indirect Registration for Anchoring Handoffs,” IETF Draft,
draft-dommety-mobileip-anchor-handoff-01.txt, Dec. 2000.
[12] E. Gustafsson, et. al., “Mobile IP Regional Registration,” IETF Draft, draft-ietfmobileip-reg-tunnel-02.txt, Mar. 2000.
[13] C. Castelluccia, L. Bellier, “Hierarchical Mobile IPv6,” IETF Draft, draft-castellucciamobileip-hmipv6-00.txt, Jul. 2000.
[15] H. Soliman, et. al., “Hierarchical MIPv6 mobility management,” IETF Draft, draft-ietfmobiliip-hmipv6-03.txt, Feb. 2001.
[16] X. Zhang, et. al., “P-MIP : Minimal Paging Extensions for Mobile IP,” IETF Draft,
draft-zhang–pmip-00.txt, Jul. 2000.
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presented by ghcho