Transcript Fast Handover

General IP Based Mobility
Mechanisms
Belghoul Farouk
Christain Bonnet
Yan Moret
Introduction
Today Many Heterogeneous Radio Access Technologies
coexist
Typically They are not compatible with each others
Internet Protocol as Common network layer
4th Generation, ALL-IP wireless and Wireline network
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IP Mobility Management, definition
Goal: Continuous TCP or UDP connection even MN
moves causes IP address changes
• MN move to change its point of attachment and reminds in the
network
• MN can change its point of attachment and the network in the
same time
Mobile IP process
• Location management..??
– IP address is key that defines the Node and its location
• Handover management ( next slide)
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Mobile IPv4, a first proposal
Home Agent
Correspondent
node
Home network
Internet
3
1. Connection and foreign agent discovery
2. FA attributes CoA to MN
3. MN registers its COA with HA.
Foreign Agent
Foreign network
Access
Router
1
2
MN
Triangular routing
Control traffic load in network
No specify handover management mechanisms
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IP Handover
Important issue in mobility management
Efficient way to Manage MN roaming from
its Old Access point to the new one.
Handoff management, caused by
• signal strength deterioration
• user mobility
D : Global MN handover Delay
Physical
handover
L3 handover
Time
MN lost phy
connections with
its old AR
MN get phy
connection
With its new AR
MN process L3
Handover
(Location
update)
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Mobile IPv4, handover Steps
CN
HA
oFA
nFA
Layer2
handover
L3 new
location
détection
L3 New
location
registration
Time
MN
MIP4

MN loses the
old link
MN obtains
new Link
 MIP4
MN gets new
CoA & sends
BU to HA
Dmip = + MIP4+
MN receives BU
from HA (end of
registration)
MIP4
Tmip = TCN,HA+THA,AR+Tradio
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Mobile IPv6
Correspondent
node
Home Agent
2
3
Home network
Internet
2
1. MN Connection , CoA auto-configuration
Access
Router
2. MN registers its COA with both HA
and its CNs.
1
MN
CN Binding update avoids triangular routing.
No tunneling on MIPv6.
Address stateless auto configuration : suppression of FAs
Ipv6 : enough IP addresses available.
Long handoff delay,
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Mobile IPv6
CN
HA
oAR
nAR
Layer2
handover
L3 new
location
détection
L3 New
location
registration
Time
MN
MIP6

MN loses the
old link
MN obtains
new Link
MN auto
configure its
new CoA
 MIP4
MN finish
registration with
HA and CNs
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Fast Handover
CN
HA
oAR
nAR
MN
Layer2
Handover
//
L3 handover
MN obtains
MN loses the
new Link
old link
MN auto
configure its
new CoA & BU
Time
Reduces the
handoff delay.
Predicts L2
handover to
anticipate L3
handover
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Fast handover,
handover
5a. Packets
forwarding
bicasting
OAR
3. OAR send
PrRtAdv:
NAR Subnet @
the MN
NAR
Agent
solicitation/advertisement
2. MN initiates
6. Informs its
arrival and
start
registration
process
Fast handovers
RtSolPr
4.
FBU
7. Packets sent
to mobile
1.MN receives L2
triggers to initiate
handover
5b. MN changes AR
Reduces the handoff latency
New L3 Care-of address establishment before the L2 movement
It is based on L2 triggers ( L2 triggers: information on MN L2 connection)
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Fast handover , data transmission
CN
oAR
oAR
Time
MN
L2 triggers allows MN obtains
MN to obtain
new CoA
NAR IPv6 prefix

MN loses
old link
oAR
forwards
packets to
NAR
MN connects to
the new link
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Fast handover,
Disadvantages:
Fast Handoff aims to reduce the handoff latency by using interaction
between the radio and IP layers to detect the mobile movements. This
can work only if the radio technology allows such interaction between
layers.( its not solution for heterogenous wireless network)
The packet loss during the handover is  * Thp.
The handoff process performances, depend of wireless network Radio
technologies, it can make problems when mobile node perform roaming
between heterogeneous network
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Mobile-IPv6 Soft handover,
In order to manage Efficiency mobility across heterogeneous radio access technologies
The development of Mobile devices with multiple physical or software-defined interfaces is
expected to allow users to switch between different radio accesses technologies
In the border of coverage Area, Soft handover allows to improve the low signal level in
wireless part of the network by the duplication and the merging of data in IP layer through
more than one AR asynchronously, in uplink and downlink.
IPv6 Soft handover Solution coexist with MIPv6 and can allows high level of QoS for realtime application.
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SHO main process
Registration process
Duplication Process
Merging Process
Handover process
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Mobile registration process
Each mobile is defined by one
or more Care of Address CoA.
PCoA private CoA is used
within MIPv6.
LCoA are local addresses,
used to define Mobile
multiples connections.
D&M agent associate PCoA
with LCoAs in order to
duplicate MN designated
packets.
The Mobile also duplicate
packets to send them throw
its multiples ARs to its CN.
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Duplication Process
Duplication & Merging agent intercepts all IP packets sent to the MN
Extracts destination PCoA, and uses registered corresponding MN
LCoAs to duplicate MN designated packets via different Access
Routers.
Duplicated packets have LCoAs as new destination address .
Insertion of merging and control information in all duplicated packets
with a sequence number in each packet.
Each duplicated packets had the same sequence number and same
sender IP address .
The MN does the same thing with uplink streams.
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Merging Process
Need to filter duplicated packets at MN and D&M
DIO information of received packet are saved in MCT table ( merging
control table)
MCT table located in MN and D&M, it defines for each correspondent, its
LCoA and serial numbers of expected IP packets.
At the reception of packet, If the DIO is included and source address has
an entry in MCT, and its serial number is not expected in MCT table The
packet is discard.
First received packet among duplicated packets, is routed to upper layer.
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Soft Handover Process
TLC
PCoA
LCoA1
LCoA2
System closes
First MN
connection
(MN, PCoA)
HA
D&M
Tunel 2
LCoA1
IP
radio
AR1
AR2
IP
radio
LCoA2
Merging process
deactivated
PCoA
MN
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Handover Process
interface priority choice is dynamic
the primary interface is always the
interface with the best connection
quality
The secondary interface is used to
perform the handover and avoid
signal strength degradation if
possible
Two signal strength thresholds are
defined. Handover threshold (H_SH),
is the threshold used in mobile IPv6
to initiate the handover. Primary
threshold (P_SH) is higher threshold,
it is used in soft handover to initiate
the secondary interface connection
process.
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Advantages of the approach
(uplink - downlink)
Uplink
Not covered by FHO bi-casting
Downlink
If more than one link interface
• D&M covers the low signal level period plus the handover
period.
• We have 2 chances to receive a packet
– Reduces jitter as 1st packet arrives faster and 2nd packet is
destroyed
– Divides by 2 the probability to loose a packet
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Where do we place D&M Agent?
In any conventional router located within the
data path in the IPv6 network
Preferably located at a median position along the
data communication path, between AR1 and AR2 and
CN.
Could be located in Access Routers.
Possibility to distribute the load between several D&M
Agents organized in a multilevel hierarchical
architecture (see next slide)
APs broadcast the address of their D&M agent using
RADV.
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Hierarchical topology of D&M Agents
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Simulation model
CN
Application
UDP
:emission
debit 1
mb/s
2001::fa::1
2001::fa::2
R1
Virtual
network
2001::E1
Virtual
network
D&M agent
2001::E0
2001::E2
HA
R2
R8
802.11
11Mb/s
R9
Ra
Rb
Rc
Rd
Re
Rf
100 m
Application
UDP
:reception
We Implement MobileIPv6 with Soft and fast
handover in Gemini2, a home made simulator
Radio technology: IEEE802.11b , at 11mb/s 23/29
Simulations Results, delays and jitters
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Simulations Results, throughput
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Prototype Implementation
In Linux Kernel 2.4.19 Based on MIPL 0.9.3.
Mobile with two WLAN IEEE802.11 interfaces.
Support of Basic Mipv6 handover and Soft Handover
A modified RADVD to dynamically broadcast the
presence and the address of D&M agent in the visited
network.
A support of Multiple DM agent without Hierarchical
architecture.
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Testbed
fec0:106:2700::2
Duplication & Merging
Agent (JECKEL)
fec0:106:2300::1
IPv6 Network
Correspondent Node
IPV6 subnet 5
fec0:106:2300::/64
fec0:106:2300::2
WLAN AP1
(Radio4)
fec0:106:1100::1
WLAN AP3 (MURRET)
WLAN AP2 (HECKEL)
fec0:106:1300::1
fec0:106:1200::1
IPV6 subnet 1
fec0:106:1100::/64
fec0:106:2300::4
fec0:106:2300::3
IPV6 subnet 2
fec0:106:1200::/64
IPV6 subnet 3
fec0:106:1300::/64
Mobile Terminal
2 Radio Interfaces
(Radio3)
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Testbed2
Home IPV6 subnet
fec0:106:2700::/64
fec0:106:2700::2
Duplication & Merging
Agent (JECKEL)
fec0:106:2300::1
Correspondent Node
WLAN AP2 (MURRET)
IPV6 subnet 5
fec0:106:2300::/64
IPV6 subnet 2
fec0:106:1300::/64
WLAN AP3
(Radio4)
WLAN AP1 (HECKEL)
IPV6 subnet 3
fec0:106:1100::/64
IPV6 subnet 1
fec0:106:1200::/64
Mobile Terminal
2 Radio Interfaces
(Radio3)
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Conclusion and future work
Solution to manage pure IP mobility in
heterogonous network
no handoff effects on real time application
Improves wireless connexion in overlapping region
Improves MIPv6 micro mobility (Transparency of the
MN’s mobility to CNs and HA).
Reduces the « ping-pong effect »
Cohabite this solution with QoS mechanisms..?
Introduce Checksum to reconstruct two
erroneous duplicated packets….?
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Related Publication
“Eurecom IPv6 soft handover “, ICWN 2003, International Conference on
Wireless Networks- June 23rd - 26th, 2003 - Las Vegas, USA.
“IP-based handover management over heterogeneous wireless networks “,
LCN 2003, 28th Annual IEEE Conference on Local Computer Networks,
October 20-24, 2003, Bonn, Germany.
Journal paper : “Mécanismes de handover pour les réseaux IP sans-fil’ to
appear in Technique et Sciences Informatiques, Revue des sciences et
technologies de l'information.( TSI journal) . To appear in January 2005.
“A Multilevel Hierarchical topology of DM agents for MIPv6 Soft
handover », World Wireless Congress SANFRANCISCO, USA 2004
« Performance comparison and analysis on MIPv6, fast MIPv6 bi-casting and
Eurecom IPv6 soft handover over IEEE802.11b »
IEEE VTC, MILAN 2004 .
“Performance analysis on IP- based soft handover across ALL-IP wireless
networks » IWUC, PORTO, Portugal 2004
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