Fault-Tolerant Design for Mobile IPv6 Networks Jenn-Wei Lin and Ming-Feng Yang Graduate Institute of...
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Transcript of Fault-Tolerant Design for Mobile IPv6 Networks Jenn-Wei Lin and Ming-Feng Yang Graduate Institute of...
Fault-Tolerant Design
for Mobile IPv6 Networks
Jenn-Wei Lin and Ming-Feng Yang
Graduate Institute of Applied Science and EngineeringFu Jen Catholic University
22
Outline
Introduction
The Proposed Approach
Simulation
Conclusion
References
33
Introduction
Mobile IPv6 Operation
AR AR
HA
CN
RegularIPv6 Router
RegularIPv6 Router
HomeNetwork
ForeignNetwork
Internet
Packets
MN
HA: Home Agent MN: Mobile Node CN: Correspondent Node AR: Access Router
44
Introduction
Mobile IPv6 Operation
AR AR
HA
CN
HomeNetwork
ForeignNetwork
Internet
1. Binding update
2. Binding acknowledgement
HA: Home Agent MN: Mobile Node CN: Correspondent Node AR: Access Router
RegularIPv6 Router
RegularIPv6 Router
Handoff
MN
55
Introduction
Mobile IPv6 Operation
AR AR
HA
CN
MN
HomeNetwork
ForeignNetwork
Internet
Packets
Tunnel packets
Triangle routing problem
Handoff
HA: Home Agent MN: Mobile Node CN: Correspondent Node AR: Access Router
RegularIPv6 Router
RegularIPv6 Router
66
Introduction
Mobile IPv6 Operation
AR
HA
CN
MN
HomeNetwork
Internet
1. Binding update
3. Binding acknowledgement
AR
ForeignNetwork
Handoff
HA: Home Agent MN: Mobile Node CN: Correspondent Node AR: Access Router
RegularIPv6 Router
RegularIPv6 Router
2. Cache the current location of the MN
Route optimization
4. Packets
77
Introduction
Motivation If a failure occurs in an HA
Its managing MNs (the failure-effected MNs) cannot perform
binding updates. If an CN sends a packet to the failure-effected MN but it does
not cache the binding information of this MN, the packet will b
e lost.
88
Introduction
Goal Propose an efficient approach to providing fault-tolerant
capability for Mobile IPv6 network. Can handle the lost packets at the faulty HA.
Not dependent on the TCP layer to avoid incurring long
recovery latency.
99
Introduction
Network Model
CN1
Backbone Network
MN
...
...
..
.
MN: Mobile Node AR: Access Router HA: Home Agent IR: Interconnection Router
CN2
HA1 HA3
AR1 AR3
IR1
AR4AR2
HA2 HA4
MN
IR3
IR5
IR2 IR4
Network Domain 1 Network Domain 3
Network Domain 2 Network Domain 4
..
.
Internet
CN: Correspondent Node
A wide-area mobile network → A number of network domains
HA: Provide the mobility support for its managing MNsAR: Assist the MNs to forward packets within a network domain.IR: Transmit packets from a network domain to another.
1010
Introduction
Failure Detection Detected by MN
MN performs a binding update to its serving HA, but it does not
receive a binding acknowledgement for a certain period of time.
Detected by CN If a packet to an MN is required to go through the faulty HA, the
sending CN will receive an ICMP destination unreachable
message.
1111
Outline
Introduction
The Proposed Approach
Simulation
Conclusion
References
1212
The Proposed Approach
Basic Idea Initially, each MN gets or updates its preferable external HA
s from its default HA. When an MN detects a failure in its default HA, assign a ne
w serving HA and retrieve lost packets.
Handoff
Assign a newserving HA
andretrieve lost packets
Failure detection
Failure detection
Handoff
Update the preferable
external HAs
Get the preferable
external HAsInitial
1313
Handoff
Assign a newserving HA
andretrieve lost packets
Failure detection
Failure detection
Handoff
Update the preferable
external HAs
Get the preferable
external HAsInitial
The Proposed Approach
Preferable External HAs
1414
The Proposed Approach
Preferable External HAs (Cont.) Initially, each HA stores the identities of other HAs based
on the order of their location distances with the HA. The network model of this paper is under a wide-area mobile net
work, not mobile Internet. The number of HAs, the distance relationship between an HA an
d others, and the addresses of all the HAs in the system can be
known whiling establishing the Mobile IPv6 network.
1515
The Proposed Approach
Preferable External HAs (Cont.) The preferable external HAs are the HAs located in the n
etwork domains having different distance with the locate
d network domain of the MN Each MN can get its preferable external HAs from its default HA
via the binding update message. The new located network domain of the MN can be inferred fro
m the MN’s care-of-address.
1616
MN
HA4
HA2
HA1
HA5
HA6
HA3
(3-hop distance)
(1-hop distance)
(1-hop distance)
(2-hop distance)
(1-hop distance)
Homenetwork domain
MN
HA4
(2-hop distance)
HA2
HA1
HA5
HA6
(1-hop distance)
(2-hop distance)
(1-hop distance)
HA3
(1-hop distance)
Homenetwork domain
The Proposed Approach
Preferable External HAs (Cont.)
Handoff
The initial preferable external HAs
HA3
HA5
HA2
HA6
HA1
The preferable external HAs after handoff
HA5
HA4
HA6
HA3
HA2
HA1
1717
Handoff
Assign a newserving HA
andretrieve lost packets
Failure detection
Failure detection
Handoff
Update the preferable
external HAs
Get the preferable
external HAsInitial
The Proposed Approach
Assign a New Serving HA
1818
The Proposed Approach
Assign a New Serving HA (Cont.)When an MN
detects a failurein its default HA
Select first (next) preferableexternal HA as new serving HA
Generate a uniqueexternal home address
Perform a binding updateto the first (next)
preferable external HA
Success
Perform a binding updatewith each communicating CN
Yes
No
In the faulty oroverloading status
Select the HA that is close tothe current location of the MN
( external home address, care-of-address)
Route optimization
1919
The Proposed Approach
Assign a New Serving HA (Cont.)
The suffix of the external home address← The MN’s MAC address
MN has aMAC address
The prefix of the external home address← The prefix of the selected external HA
The suffix of the external home address← Use the MD5 hash function to generate
Combine the prefix and the suffixof the external home address
Combine the prefix and the suffixof the external home address
unique
Yes
No
Yes
No
Generate a uniqueexternal home address
2020
Handoff
Assign a newserving HA
andretrieve lost packets
Failure detection
Failure detection
Handoff
Update the preferable
external HAs
Get the preferable
external HAsInitial
The Proposed Approach
Retrieve Lost Packets
2121
The Proposed Approach
Retrieve Lost Packets (Cont.) When an CN would like to send a packet to the failure-
effected MN but it has not the MN’s binding information
in its binding cache. The packet will be forwarded through the faulty HA, and then
lost.
2222
IR1CN1
Faulty
default HA1
Failure
MN1
2. Tracking the sending ICMP destination unreachable messages
The undeliverable packet list
Destination address
MN1
::
Source address
CN1
::
4. Storing the undeliverable packets
The undeliverable packet buffer
Destination address
MN1
::
Undeliverable packet
Packet1
::
The Proposed Approach
Retrieve Lost Packets (Cont.) Before a packet is intercepted by a HA, the packet is first
received by a corresponding IR. Therefore, CN will receive
an ICMP destination unreachable message from IR. Ask the IR to trace its sending ICMP destination unreachable
messages to form an undeliverable packet list. Ask the CN to store the undeliverable packets in its undeliverable
packet buffer .
1. Packet1
3. ICMP destination unreachable
2323
The Proposed Approach
Retrieve Lost Packets (Cont.) The recovery process of the undeliverable packets
IR1
Faulty
default HA1
Failure
IR2
New
serving HA2
CN1 CN2 CN3
MN 1.a. Binding update
1.b. Binding update
3. Binding error and
Undeliverable packet recovery
2.a. Binding acknowledgement
2.b. Finding the undeliverable packet destined to the MN
4. Solicited binding update
5. Updating the binding information of the MN and finding the undeliverable
packets destined to the MN
6. Re-sending theprevious undeliverable
packet destined to the MN
2424
Outline
Introduction
The Proposed Approach
Simulation
Conclusion
References
2525
Simulation
Overhead of Tolerating Faulty HA The information about preferable external HAs is attache
d on the binding acknowledgement message. The overhead of the extended binding acknowledgement
message :
The number of attached external HAsis based on the required fault-tolerant capability of the proposed approach.
Allowing 9 HAs to simultaneously fail in the system.
2626
0
0.2
0.4
0.6
0.8
1
0 5 10 20
Number of failure-effected MNs
Tota
l bin
ding
upd
ate
late
ncy
(se
cond
s) Redundancy-basedapproachProposed approach
Simulation
Overhead of Tolerating Faulty HA (Cont.) Each failure-effected MN can select its preferable external
HA as the new serving HA after its default HA fails. The binding update latency for failure-effected MNs :
The preferable external HA is close to the current location of the failure-effected MN.
The failure-effected MNs can simultaneously perform binding updates to different new serving HAs.
2727
Simulation
Overhead of Lost Packet Recovery The undeliverable packets will be retrieved when a
failure-effected MN performs a binding update. The space overheads are mainly determined by the binding
update interval. The space overhead introduced by the lost packet recovery :
0.00.51.01.52.02.53.0
2 4 6 8 10
Binding update interval (seconds)
Size
s of
the
unde
liver
able
pack
et li
st (K
byte
s)
The undeliverable packet list The undeliverable packet buffer
0102030405060
2 4 6 8 10
Binding update interval (seconds)Si
zes of
the
unde
liver
able
pack
et b
uffer
(Kby
tes)
2828
Outline
Introduction
The Proposed Approach
Simulation
Conclusion
References
2929
Conclusion
An Efficient Approach to Tolerating the HA Failure i
n a Mobile IPv6 Network System. Consider how to recover from the lost packets at the fault
y HA. The simulation results show that the incurred overhead is
very small. If The probability that many HAs simultaneously fail is small The binding update interval is not too long,
3030
References
3131
References
3232
Thank you for your listening.