Transcript Ad-hoc networking -

NATO
Consultation, Command and
Control Agency
Ad-hoc Networking: Infrastructure-free
Communications for Military Operations
Michael Winkler, Marco Bartolozzi
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Outline of Presentation
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Motivation for Ad-hoc Networking
Main Concepts
Military Requirements
Security Issues
 Simulation versus Emulation
 The NC3A Prototype Network
 Set-up
 Measurements & Results
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(M. Winkler)
(M. Bartolozzi)
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Motivation for Ad-hoc Networking
 NATO Network Enabled Capability Feasibility Study:
“To guarantee the necessary service availability,
connectivity and agility, the networking and information
infrastructure (NII) should exploit the functionality of
mobile ad-hoc networks (MANET).”
 NATO C3 Technical Architecture:
“Ad-hoc networking is of increasing interest for a
diverse set of applications on the battlefield, including
distributed sensor and munitions networks and flexible
and rapidly deployed HQ wireless LANs.”
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Main Ideas of Ad-hoc Networking (1)
 Multi-hopping
 Communication nodes are relaying traffic for each other
 Normally based on wireless transmissions
 Special-purpose routing, possibly geocast routing
 Extension of coverage due to additional nodes
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Main Ideas of Ad-hoc Networking (2)
 Distributed network operations
 No centralized instance
 Network self-organization
 Self-healing properties
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Main Ideas of Ad-hoc Networking (3)
 Infrastructure-free information exchange
 Communication is possible where communication devices
exist
 No need to install any infrastructure
 Thus achieving overall
 High flexibility
 High adaptability
 Support for static as well as mobile users
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Specific Military Requirements
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Rapid deployment capability
Absence of a single point of failure
Self-healing properties
Encryption capability for classified data transfer
Node authentication
Secure routing
Ideally predictable Quality of Service
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Types of Ad-hoc Networks
 Mesh Networks
 With many
interconnection
points with fixed
infrastructure
 Here hybrid
architecture
using WiMAX
& WLAN
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Types of Ad-hoc Networks
 ... besides Mesh Networks:
 Sensor Networks
 Connecting many sensors
 Power conservation critical
 Very limited computing power and memory size
 Mobile Ad-hoc Networks (MANETs)
 Wireless
 Supporting mobile users
 Stand-alone or as extension of fixed infrastructure
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MANET for Civil Military Cooperation
 Example: Disaster recovery
 Supporting NGOs
 Extending the coverage
Reach-back
to strategic network
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NGO: Non-governmental organization
MANET: Mobile Ad-hoc Network 10
MANET for Civil Military Cooperation
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Example: Disaster recovery
Supporting NGOs
malicious
Extending the coverage
user
Need for security measures
Reach-back
to strategic network
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NGO: Non-governmental organization
MANET: Mobile Ad-hoc Network 11
Security Issues
 Confidentiality and integrity of data can be ensured by
the use of IP encryption devices
 Protection of the network availability also important
 Possible attacks:
 Jamming
 Routing disruption, e.g. by flooding with routing messages
 Traffic forwarding attacks, e.g. by setting-up black hole
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Securing Routing Protocols
 Main approach: Add digital signature field to the routed
packets
 Proposals for secure routing algorithms exist,
e.g. secure OLSR and secure AODV
 However
 Key distribution and key updates demanding
 Increased management traffic
 Problematic to include unknown nodes
 Need for further evaluation and practical experience
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Directions for Further Research
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Pervasive resilience & security
Efficient routing algorithms
Multi-casting and geo-casting
Real-time services & end-to-end QoS
Enhanced scalability
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Ad-hoc Networking Experimentation
 Experimentation on ad-hoc networking has been so far
driven by the need to:
Evaluate and compare different ad-hoc routing
protocols
Validate specific operational scenarios
Encourage progress on the technology itself
 It is generally made using two different approaches:
Simulation
Emulation
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Simulation versus Emulation
 Simulation starts from software
It is based on software routines and algorithms that
replace and resemble the behaviour of the original
hardware system
It aims at:
Achieving a very high degree of repeatability
Reducing experimentation costs
 Emulation starts from hardware
It is fully or partially made by the same hardware used
in a field deployment
It aims at obtaining a good compromise between
repeatability and accuracy
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Ad-hoc Experimentation Systems
 Simulators:
 NS-2
 Qualnet
 Glomosim
A
Emulations
real world
experiments
APE
CMU
Simulations
EWANT
ORBIT
SARNOFF
complex
 Emulated systems
 Sarnoff
 Ewant
 Orbit
 APE
 CMU
NS-2
QUALNET
GLOMOSIM
simple
R
A = Accuracy (degree of resemblance to real-world experiments)
R = Repeatability (capability to effectively repeat tests under the
same initial conditions)
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The NC3A-4F Testbed
• #4 DELL NOTEBOOKS
• LINUX FEDORA CORE 5
• Kernel 2.6.16-1.2096_FC5
• Senao WLAN PCMCIA cards NL-5354CB+ (802.11g)
• Madwifi-ng v. 0.9.4.5 Atheros driver for FC5
• Static IP addressing
Fedora
• OLSR v. 0.4.10 routing protocol from olsr.org
Feasible
4F
Flexible
Fieldable
• Applications: ping, iperf, ethereal, X-Lite softphone
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Testbed Scenarios
host8
Mesh Topology
host6
host2
host3
Chain Topology
host2
host3
host6
host8
Mesh-to-Chain
M
Changing Topology
State-Machine
C
Chain-to-Mesh
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Throughput and RTT
 Mesh topology (1 hop)
 UDP throughput: 8 Mb/s
 TCP throughput: 11 Mb/s
 Round Trip Time: 0,67 ms
 Chain topology (3 hops)
 UDP throughput: 2,5 Mb/s
 TCP throughput: 650 Kb/s
 Round Trip Time: 5,5 ms
From mesh to chain (1 to 3 hops), RTT increases 10 times,
UDP throughput reduces by 70%, TCP throughput reduces
by 90%;
→ SCALABILITY is a crucial issue for ad-hoc networking!
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Test with UDP data transfer and changing
topology
bytes
 UDP data transfer at 300
Kb/s using Iperf
 Topology is changed
from mesh to chain using
a MAC filtering script
launched from one of the
hosts
 The script uses SSH to
access other hosts and
load / unload access lists
based on MAC addresses
Iperf
UDP
secs
mesh
chain
mesh
bytes
Iperf
UDP
SSH
TCP
secs
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VoIP test with high-rate TCP and changing
topology
bytes
 VoIP phone call
established using XLite Softphone (SIP
protocol)
 TCP data transfer at
11 Mb/s using Iperf
Iperf
TCP
RTP
VoIP
secs
 Voice quality as
perceived by the
callees was very
good.
Communication on
both directions was
never interrupted
RTP
VoIP
mesh
chain
mesh
bytes
SSH
TCP
secs
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Testbed Conclusions
 The NC3A-4F testbed aimed at proving the functionality of the ad-hoc
networking technology, using commercial-of-the-shelf hardware and
software.
 UDP and TCP data transfer and Voice over IP communication have been
tested over the NC3A-4F testbed, with satisfactory results overall.
 The tests showed that an increasing number of intermediate hops brings
significant reduction in terms of overall bandwidth, affecting particularly
intensive-rate applications.
 Low/medium-rate applications such as Voice over IP showed not to be
significantly affected by multi-hopping.
 Scalability of the ad-hoc networking solution remains a crucial issue that
needs further investigation, in order to provide a consistent feedback on
how and with which constraints ad-hoc networking can be successfully
deployed in the theatre.
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Contact Information
NC3A The Hague
Visiting address:
Dr.-Ing. Michael Winkler
Oude Waalsdorperweg 61
2597 AK The Hague
Telephone +31 (0)70 3743262
[email protected]
Telephone +31 (0)70 3743000
Fax +31 (0)70 3743239
Postal address:
NATO C3 Agency
P.O. Box 174
2501 CD The Hague
The Netherlands
Dr.-Ing. Marco Bartolozzi
Telephone +31 (0)70 3743465
[email protected]
Contacting NC3A
NC3A Brussels
NC3A The Hague
Visiting address:
Visiting address:
Bâtiment Z
Avenue du Bourget 140
B-1110 Brussels
Telephone +32 (0)2 7074111
Fax +32 (0)2 7078770
Oude Waalsdorperweg 61
2597 AK The Hague
Postal address:
NATO C3 Agency
Boulevard Leopold III
B-1110 Brussels - Belgium
Postal address:
NATO C3 Agency
P.O. Box 174
2501 CD The Hague
The Netherlands
Telephone +31 (0)70 3743000
Fax +31 (0)70 3743239
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