Improving network mobility in HAP networks

First COST 297 – HAPCOS Workshop – York, UK
Improving Network Mobility
in HAP Networks
Andrej Vilhar,
Vilhar, Roman Novak
Department of Communication Systems
Jožef Stefan Institute, Ljubljana, Slovenia
26 - 27 October 2006
First COST 297 - HAPCOS Workshop - York, UK
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Outline
Issues related to network mobility (and proposed solutions)
• route optimization
• handoff efficiency
Basic concepts of multihoming
Simulation aspects
• simulation scenario, assumptions, tools, methods etc.
Performance analysis
• route path optimality
• handoff efficiency
Conclusion
26 - 27 October 2006
First COST 297 - HAPCOS Workshop - York, UK
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IP mobility: end-nodes
Mobile IPv6
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• uninterruptible service, route optimization
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First COST 297 - HAPCOS Workshop - York, UK
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IP mobility: mobile networks
Airplanes, ships, buses, trains etc.
NEMO extensions of Mobile IPv6
• uninterruptible service, no route optimization
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4
1st issue: How to
achieve optimal
route paths for
mobile networks?
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First COST 297 - HAPCOS Workshop - York, UK
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Public transport vehicles
The movement is limited to certain area and/or can be
quasi-deterministic.
This implies route optimization problem could be alleviated by
carefully selecting the HA’s location.
If single HA is not sufficient, multiple HAs can be introduced.
Possible solution for route
optimization problem.
26 - 27 October 2006
First COST 297 - HAPCOS Workshop - York, UK
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Handoff procedures
When mobile network moves in a topology a set of procedures
occur:
During the
Mobile router:
•
•
•
•
detects the movement on a link layer,
detects the movement on a network layer,
forms a new care-of-address,
informs home agent by sending binding update.
Home agent:
• confirms by sending binding acknowledgement.
26 - 27 October 2006
First COST 297 - HAPCOS Workshop - York, UK
execution of the
procedures,
packets are
being lost.
2nd issue:
How to
achieve
smoother
handoffs?
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Multiple active egress interfaces
By keeping multiple egress interfaces active, packets can
be saved from loss, even when switching between different
access networks.
Possible solution for achieving
smoother handoffs.
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First COST 297 - HAPCOS Workshop - York, UK
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Multihoming
A multihomed node is defined by [1] as a node with multiple
addresses:
• either due to multiple prefixes advertised in the access link
• or because the node has multiple interfaces.
According to such definition the mobile network with:
• multiple HAs has several home addresses
• multiple active egress interfaces has several addresses
multihomed
Besides achieving route path optimality and smoother handoffs,
multihoming offers other benefits [1]:
• Load sharing/load balancing, bi-casting, redundancy/fault-recovery.
[1] T. Ernst, N. Montavont, R. Wakikawa, E. Paik, C. Ng, K. Kuladinithi, and T. Noel. (2005,
October) Goals and benefits of multihoming. IETF Internet Draft.
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First COST 297 - HAPCOS Workshop - York, UK
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Multihoming configurations
To identify different possible multihoming configurations the
following taxonomies were suggested [2][3]:
• End-nodes:
• Mobile networks:
(iface, HoA, CoA)
(MR, HA, MNP)
To fully describe a certain NEMO configuration analyzed in our
paper, we suggest the taxonomy:
• (MR, HA, MNP, iface, CoA)
[2] N. Montavont, R. Wakikawa, T. Ernst, C. Ng, and K.
Kuladinithi. (2005, October) Analysis of multihoming in
mobile IPv6. IETF Internet Draft.
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[3] C. Ng, E. Paik, and T. Ernst. (2005, October)
Analysis of multihoming in network mobility support.
IETF Internet Draft.
First COST 297 - HAPCOS Workshop - York, UK
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HAP important configurations
(MR, HA, MNP, iface,
iface, CoA)
CoA)
(1,1,1,N,1) – multiple interfaces, but only one active CoA – very
basic,
(1,1,N,N,N) – multiple advertised prefixes – allows end-nodes being
multihomed,
(1,N,1,N,N) – multiple HAs support single MR – despite the fact
multihoming is transparent to end-nodes (single
MNP), they do benefit from it,
(N,1,1,N,N) – multiple MRs – one MR per train car
(N,1,N,N,N) – multiple MNPs – better support for train modularity
26 - 27 October 2006
First COST 297 - HAPCOS Workshop - York, UK
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Simulated configurations
(MR, HA, MNP, iface,
iface, CoA)
CoA)
Standard MIP configuration - (1,1,1,2,1):
• used as a reference.
Multihomed MIP configuration - (1,2,1,2,2):
• two CoAs in parallel,
• two HAs,
• HAHA protocol.
26 - 27 October 2006
First COST 297 - HAPCOS Workshop - York, UK
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Simulation scenario, assumptions and tools
A train traveling from western to
eastern part of Slovenia.
HAP
best choice
LOS
NLOS
UMTS,
WiMAX
full coverage
MR
Empirical LOS data (two-state
channel model) for this particular
railway track was taken into account.
OPNET Modeler simulation tool.
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First COST 297 - HAPCOS Workshop - York, UK
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Simulation topology
HA
HA
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First COST 297 - HAPCOS Workshop - York, UK
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Assessment of route path optimality
If route path is optimal:
• end-to-end delays lower higher throughput for TCP-based applications,
• resource consumption reduced backhaul link utilization is lower.
26 - 27 October 2006
First COST 297 - HAPCOS Workshop - York, UK
FTP file transfer
from CN to MN
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Assessment of route path optimality
(CN in global network)
network)
LOS
Visibility [LOS/NLOS], Backhaul link utilization [%]
Visibility [LOS/NLOS], Throughput [Mbit/s]
1.2
HAGS
1
HAHAP
0.8
0.6
0.4
0.2
NLOS
40
LOS
30
HAHAP
20
10
HAGS
0
NLOS
0
500
550
600
650
700
750
800
500
550
600
Time [s]
Throughput
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650
700
750
800
Time [s]
Backhaul link utilization
First COST 297 - HAPCOS Workshop - York, UK
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Assessment of route path optimality
(CN in HAP network)
network)
Visibility [LOS/NLOS], Backhaul link utilization [%]
Visibility [LOS/NLOS], Throughput [Mbit/s]
4.8
LOS
4
HAHAP
3.2
2.4
HAGS
1.6
0.8
NLOS
80
LOS
60
HAGS
40
20
HAHAP
0
NLOS
0
500
550
600
650
700
750
800
500
550
Time [s]
Throughput
600
650
700
750
800
Time [s]
Backhaul link utilization
Standard MIP route optimality depends on CN, HA and LOS
Multihomed MIP routes are always optimal
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First COST 297 - HAPCOS Workshop - York, UK
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Assessment of handoff efficiency
If handoff is efficient:
• less (none) packets are lost TCP-based flows are not appropriate
for assessment due to built-in back-off algorithm
Voice conversation
between CN and
MN
100 packets/s,
57 bytes/packet
in both UL and DL
26 - 27 October 2006
First COST 297 - HAPCOS Workshop - York, UK
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Assessment of handoff efficiency:
efficiency:
standard MIP vs.
vs. multihomed MIP
LOS
NLOS
HAP HA:
UL: i-face TER
DL: i-face TER
1 HA, 1 CoA
(standard
MIP)
MR
HAP
HA
L2
GS
L2
GS HA (P):
DL: i-face TER
UL: i-face TER
HAP HA:
DL: i-face TER
LOS
NLOS
2 HA, 2 CoA
(multihomed
MIP)
MR
TER
HAP
HA
L2
GS
HA
L2
GS HA (P):
DL: i-face TER
UL: i-face TER
HAP HA:
DL: i-face TER
TER
RS
RS
RA
RA
all packets lost
BU
HAP HA:
DL: i-face HAP
UL: packets lost
BA
UL: packets
discarded by
non-primary HA
GS HA (P*):
DL: i-face TER
UL: i-face TER
HAP HA (P):
DL: i-face HAP
P, BU
BA
BIU
BIA
GS HA:
DL: i-face HAP
HAP HA (P):
DL: i-face HAP
UL: i-face HAP
HAP HA:
DL: i-face HAP
UL: i-face HAP
all packets lost
MR
TER
L2
HAP
HA
GS
L2
MR
GS
HA
TER
L2
HAP
HA
GS HA:
DL: packets lost
HAP HA (P):
DL: packets lost
UL: i-face TER
L2
RS
RA
all packets lost
UL: packets
discarded by
non-primary HA
P, BU
GS HA (P):
DL: i-face TER
HAP HA (P*):
DL: packets lost
UL: i-face TER
BIU
BA
BIA
BU
MR
GS HA (P):
DL: i-face TER
HAP HA:
DL: i-face TER
UL: i-face TER
HAP HA:
DL: i-face TER
UL: packets lost
BA
HAP
HA
L2
HAP HA:
DL: i-face TER
UL: i-face TER
GS
L2
TER
RS
RA
all packets lost
BU
.
.
.
.
.
.
.
.
.
.
.
.
MR
HAP
HA
L2
.
.
.
GS
HA
L2
.
.
.
GS HA (P):
DL: i-face TER
UL: i-face TER
HAP HA:
DL: i-face TER
TER
.
.
.
.
.
.
GS HA (P):
DL: i-face TER
UL: i-face TER
HAP HA:
DL: i-face TER
.
.
.
UL: i-face TER … optimal path
UL: i-face TER … unoptimal path
(P) … primary
(P*) … old primary
26 - 27 October 2006
First COST 297 - HAPCOS Workshop - York, UK
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Assessment of handoff efficiency:
efficiency:
standard MIP vs.
vs. multihomed MIP
120
multihomed MIP
80
40
NLOS
15
Visibility [LOS/NLOS], Packet loss [packets]
Visibility [LOS/NLOS], Packet loss [packets]
standard MIP
LOS
160
standard MIP
LOS
12
9
6
3
NLOS
multihomed MIP
0
300
400
500
600
700
800
0
300
400
Time [s]
500
600
700
800
Time [s]
Packet loss on HAP interface
(LOS to NLOS transition)
Packet loss on terr. network interface
(NLOS to LOS transition)
Standard MIP: losses on both interfaces
Multihomed MIP: no loss on terr. network interface, lower loss on HAP interface
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First COST 297 - HAPCOS Workshop - York, UK
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Conclusions
Multiple HAs can improve route optimality for quasi-deterministic
movements.
• The throughput increases, the load on backhaul link is reduced.
Simultaneous usage of multiple access interfaces is beneficial in
terms of handoff efficiency.
Further challenges related to multihoming:
• Handoff anticipation, link load balancing, efficient coordination
between MRs.
Other important challenges:
• nested mobility,
• hierarchical approach to mobility provision.
26 - 27 October 2006
First COST 297 - HAPCOS Workshop - York, UK
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First COST 297 – HAPCOS Workshop – York, UK
Thank you!
andrej.v
ilhar@
@ijs.si
ndrej.vilhar
26 - 27 October 2006
First COST 297 - HAPCOS Workshop - York, UK
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