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First Page
Index1
Overview of SAHNRouting in SAHN (SAHNR)
Simulation ResultsFuture Work
Current Project StatusAcknowledgements
Definition1SAHN
Definition
SAHN Definition
An alternative to
existing broadband
services for
cooperative users
using wireless
technology at an
affordable cost
Why not existing
solutions1
Dialup and high speed services (e.g. cable modems & xDSL)
• Provide mostly asymmetric bandwidth utilization
• Inadequate for file transfer, X protocol, interactive graphical programs etc
• Require costly wiring infrastructure
• Impose service charges
• Not widely available
Why not existing solutions2
Nokia RoofTop and other packet radio schemes
• Mostly centrally controlled
• Provide inadequate QoS
• Not optimized for Ad-Hoc networks
SAHN Motivation
• Commercial broadband solutions are:
– Expensive
– Not universally available
– Provide restricted service
• Commercial service restrictions:
– Asymmetric traffic characteristics
– Poor QoS management
– Only supports Internet protocols
– Limited security, management and accounting support
Motivation
• Provide services not offered by commercial service providers
• Bypass expensive infrastructure for broadband
• Provide symmetric bandwidth
• WLAN in inadequate wiring infrastructure
• Bypass ongoing service charges for Telcos independent traffic
Motivation2
• Feature QoS
• Security throughout all layers
• Utilizing link states (e.g. available bandwidth, link stability, latency, jitter and security) to select suitable routes
• Avoid selfish routing strategy
• Proper resource access control and management
SAHN
Definition
• Ideal for cooperative nodes. E.g. spread over a suburban area, connecting houses and business
• Topology is quasi static
• Uses wireless technology
• Multi-hop QoS routing
• Decentralized
• Symmetric broadband, multi Mbits/sec bandwidth
• Security
SAHN Definitio2
• No charges for SAHN traffic
• SAHN services
run alongside
TCP/IP• Conceived by
Ronald Pose & Carlo Kopp
Application
Presentation
Session
Transport
Network
Data Link
Physical
TCP/UDP
IP
Application
Presentation
Session
Transport
Network
Data Link
Physical
TCP/UDP
IP
SAHN
e.g. IEEE 802.11 variants
e.g. IEEE 802.11 variants
AUDIO
VEDIO
OTHER
Who should be using
• Home office and professionals requiring broadband connection to organisation’s systems
• Internetworking of businesses with their offices spread through a suburb, campus buildings etc
• People living around their campus can access the university’s network via SAHN without expensive commercial Telecom services
Users2
• Cooperative users can communicate and share a speedy Internet connection with each other via SAHN
• Houses linked with video clubs can download video streams on demand
• Groups with online gaming interests
Standalone SAHN
• Appears to host like a cable modem
• Functionally more like a
RF LAN repeater
• Embedded
microprocessor
protocol engine
implements all SAHN protocols and manages and configures the system
• Each SAHN node has at least 2 wireless links
• Capable of achieveing link rate throughput
SAHN Issue1
• Investigating wireless technology
• An appropriate routing solution
• A robust node authetication scheme
• Appropriate security models for various layers
• Integrating SAHN specific hardware and software solutions at minimum cost
• A suitable business model for exploiting the SAHN concept
Design Issues2
• Investigating wireless technology
• An appropriate routing solution
• A robust node authetication scheme
• Appropriate security models for various layers
• Integrating SAHN specific hardware and software solutions at minimum cost
• A suitable business model for exploiting the SAHN concept
References1
• R. Pose and C. Kopp. Bypassing the Home
Computing Bottleneck: The Suburban Area
Network. 3rd Australasian Comp. Architecture
Conf. (ACAC). February, 1998. pp.87-100.• A. Bickerstaffe, E. Makalic and S. Garic. CS
honours theses. Monash University.
www.csse.monash.edu.au/~rdp/SAN/. 2001• Paul Conilione, “QoS for Suburban Ad Hoc
Networks”. Honours Interim Presentation,
CSSE, Monash University, 5th June 2003
Index2
Overview of SAHNRouting in SAHN (SAHNR)
Simulation ResultsFuture Work
Current Project StatusAcknowledgements
SAHN Goals
• Wireless medium inherently vulnerable to– Eavesdropping– DoS attacks– Node masquerading
Requires security policies implemented at all levels
• Wireless technologies (e.g. 802.11) do not feature resource– Access control– Management
Requires higher level protocols
SAHN Goals
• Ad-Hoc wireless networks have to– Handle node/link failures– Find routes on demand– Route packets with QoS
Requires an efficient on-demand routing solution
Existing Routing0
• Table Driven
– Maintains multiple tables for route information
– Constant overhead for routing control packets
– e.g. DSDV, WRP, GSP, FSR, HSR
• On Demand
– Finds routes on demand– Reduced overhead of routing control packets– e.g. AODV, DSR, AOMDV, MSR, TORA,
ABR
Existing Routing1
• Hybrid– Employes both table driven and on
demand routing techniques– e.g. LANMAR
• Others
– Ensures QoS routing
– Can be any of the above three types
Existing Routing1
• Dynamic source routing (DSR) – On demand– Emplyes source routing– Can find multiple routes– Network overhead increases for carrying
source routes– No security at network layer– Does not consider QoS for route selection– Does not feature load balancing
Existing Routing1
• Ad Hoc on demand distance vector routing (AODV)– On demand– Cannot find multiple routes to a destination– No security at network layer– Does not consider QoS for route selection– No support for load balancing
Why Hybrid Approach1
Existing solutions do not feautrure one or more of the following attributes– Multiple routes to a destination– Resource Access Control– QoS– Load balancing– Security at network layer– Optimization for quasi-static networks
SAHNR1
• Keeps up-to-date neighbour information
• Employs source routing for route discovery
• Maintains routes dynamically
– Employs features of DSR.
e.g. gratuitous Route replies,
salvaging data/error packets etc.
SAHNR1
• Decreases network overhead– Excludes source route in every data packet
• Avoids selfish/uncoordinated routing strategy– Makes use of available paths having QoS– Chooses least congested paths– Balances load among available paths
• Features network level security by– Node authentication– Encryption of packet header information
SAHNR2
• Neighbour Discovery and Authentication
Periodically and on demand
• Route Discovery
On demand
• Data Transmission
On demand
• Route Maintenance
Periodically and on demand
Neighbor
Discovery1
Performed – When a node is powered up– After an idle period if needed
Main tasks are– Node authentication– Negotiation of security scheme for network layerRequires– ‘Hello’/‘Hello Reply’ packets
SAHNId
TypeLocal
SourceAddress
TotalSize
CRCLevel1
EncryptedLevel2 Payload
TransmissionTime (TT)
Sharedkey
Level 1
Level 2
Nehbourhood Discovery2
Node N wants to join SAHN
NS
G
H
FE
X
D
C
B
Nehbourhood Discovery2
N Generates aShared Key for
encryptionduring
transmittingdata to
neighbors
Encrypts level 2payload using
own Secret Key& generates
cipher text C1
Encrypts C1using SAHNPublic Key &
generatescipher text C2
Prepends C2with the
remaining`Hello'packet
Nehbourhoo
d Discovery2
HelloNS
G
H
FE
X
D
C
B
Hello
HelloHello
Hello
Node N broadcasts Hello packets and S, B, C, F, G receive them
Neighbor
Discovery3
Registers N as avalid SAHNnode. The
Shared Key issaved for future
encryption/decryption of
level 2 header ofthe sent/received
packets.
DeciphersC1 usingNode N's
Public KeyDeciphers C2 bySAHN Secret Key& generates C1
`Hello' packet?
Yes
Searches thedistributed and secured key
database for N'sPublic Key
Found
NotFound
Discardsthe invalid
packet
No
Processesfor other
packet types
Neighbor Discovery3
NS
G
H
FE
X
D
C
BReply
Reply
Reply Reply
Reply
Nodes S, B, C, F and G unicast Hello Reply packet to N
Neighbor
Discovery3
NS
G
H
FE
X
D
C
B
Now node N becomes a part of SAHN
Route Discovery1
• Performed if– Route is not present in routing table– Route has expired
• Requires
– RREQ and RREP packets
• Uses negotiated encrytion/decryption key for RREQ/RREP packet encrytion/decryption
SAHNId
TypeLocal
SourceAddress
TotalSize
CRCLevel1
EncryptedLevel2Header
TransmissionTime (TT)
GlobalSourceAddress
GlobalDestination
Address
RAQL. Each node'saddress & QoS values
Level 1
Level 2 SEQ HCHTL
Level 2 Data
Route
Discovery2
S wants route to X. S broadcasts RREQ packets to its neighbours
NS
G
H
FE
X
D
C
B
RREQ(S,QoSS)
RREQ(S,QoSS)
Route
Discovery2
Intermediate Nodes e.g. B does not have a route to Node X– B updates its routing table/forwarding table
with unknown information– Appends its address and QoS information
in RAQL– Broadcasts RREQ to its neighbours
Route Discovery2
NS
G
H
FE
X
D
C
B
RREQ(S,QoSS)
RAQL={(S,QoSS)}
RAQL={(S,QoSS)(B,QoSB)}
RAQL={(S,QoSS)(B,QoSB)(C,QoSC)(E,QoSE)}
Route Table::(X,QoSX):
Route Discovery3
• Intermediate node H has routes to X– H updates its routing/forwarding table with
unknown information– Appends H and QoSH with RAQL– Appends route to X and QoS information
with RAQL– Reverses RAQL– Forwards RREP to E from RAQL
• Same steps for X if it receives a RREQ
Route Discovery3
NS
G
H
FE
X
D
C
B
Route Table:::
RAQLE{(S,QoSS)(B,QoSB)(C,QoSC)(E,QoSE)}
Route Table(S,QoSS)(B,QoSB)(C,QoSC)(E,QoSE):(X,QoSX):
RAQLH{(X,QoSX)(H,QoSH)(E,QoSE)(C,QoSC)(B,QoSB)(S,QoSS)}
Route Discovery4
• Intermediate Nodes receive RREP packets– Update their routing/forwarding tables– Update QoS values of RAQL– Forward RREP
• Node S receives RREP packets– Updates its routing/forwarding table– Records routes– Selects suitable routes with acceptible
QoS to send data
Route Discovery4
NS
G
H
FE
X
D
C
B
Route Table:(B,QoSB)(C,QoSC)(E,QoSE)(H,QoSH)(X,QoSX)::
Route Table(S,QoSS)(B,QoSB)(C,QoSC)(E,QoSE):(X,QoSX):
RAQLH{(X,QoSX)(H,QoSH)(E,QoSE)(C,QoSC)(B,QoSB)(S,QoSS)}
RAQLE{(X,QoSX)(H,QoSH)(E,QoSE)(C,QoSC)(B,QoSB)(S,QoSS)}
RAQLC{(X,QoSX)(H,QoSH)(E,QoSE)(C,QoSC)(B,QoSB)(S,QoSS)}
RAQLB{(X,QoSX)(H,QoSH)(E,QoSE)(C,QoSC)(B,QoSB)(S,QoSS)}
Data Transmission1
• First few data packets contains full RAQL• An intermediate node
– Updates its routing/forwarding tables with unknown information
– Forwards data packet to the next node from RAQL
TotalSize
Data to be TransmittedCRC
Level3Level 3
SAHNId
TypeLocal
SourceAddress
TotalSize
CRCLevel1
EncryptedLevel2Header
TransmissionTime (TT)
GlobalSourceAddress
GlobalDestination
Address
Level 1
Level 2
SEQ HCHTLEncrypted Level3
Payload
EncryptedLevel 3Payload
RAQL
Data Transmission2
• Remaining data packets do not contain RAQL• An intermediate node
– Finds the next node from the forwarding table with <Global Source, Global Destination>
– Updates Local Source with its own address– Updates its routing/forwarding tables
TotalSize
Data to be TransmittedCRC
Level3Level 3
SAHNId
TypeLocal
SourceAddress
TotalSize
CRCLevel1
EncryptedLevel2Header
TransmissionTime (TT)
GlobalSourceAddress
GlobalDestination
Address
Level 1
Level 2
SEQ HCHTL Encrypted Level3 Payload
EncryptedLevel 3Payload
Route Maintenance1
Takes actions if
• A link fails
• A route error control packet is received
• Data packets are recieved for unknown destinations
• A neighbour/route/forward table entry is too oldSAHN
IdType
LocalSourceAddress
TotalSize
CRCLevel1
EncryptedLevel2Header
TransmissionTime (TT)
GlobalSourceAddress
GlobalDestination
Address
RAQL. Each node'saddress & QoS values
Level 1
Level 2 SEQ HCHTL
Level 2 Data
UnreachableNode
Address
Route Maintenance2
If the route maintenace module senses a link failure, it
• Tries to find alternate route to destination
• Sends RERR of the broken link to its neigbours
• Deletes corresponding entries of broken links from its neighbour/route/forward tables
Route Maintenance3
If a node receives a RERR packet the route maintenance module
– Sends RERR to its neigbours
– Deletes corresponding entries from its
neighbour/route/forward tables
SAHNId
TypeLocal
SourceAddress
TotalSize
CRCLevel1
EncryptedLevel2Header
TransmissionTime (TT)
GlobalSourceAddress
GlobalDestination
Address
RAQL. Each node'saddress & QoS values
Level 1
Level 2 SEQ HCHTL
Level 2 Data
UnreachableNode
Address
Route Maintenance4
If a node receives a data packet for unknown destination, the route maintenance module
– Tries to find a route to the destination
If it fails, it
– Sends RERR to the source of the data packet
Reference2
• A. Bickerstaffe, E. Makalic and S. Garic. CS
honours theses. Monash University.
www.csse.monash.edu.au/~rdp/SAN/. 2001• P. Misra. Routing Protocols for Ad Hoc Mobile
Networks. www.cis.ohio-state.edu/~jain/cis788-99/adhoc_routing/index.html. 02/07/2000
Index2
Overview of SAHNRouting in SAHN (SAHNR)
Simulation ResultsFuture Work
Current Project StatusAcknowledgements
Simulation Setup
110
1 2 3 4 5
6 7 8 9 10
13 14 15
12 17
16
• Node 0 sends node 11 8000 items of 1460 bytes each between simulated times 30 sec to 10 hr through FTP. • Node 11 sends node 0 11000 items of 1400 bytes each between simulated times 70 sec to 10 hr through FTP. • Node 12 sends node 13 9000 items of 1500 bytes each between simulated times 100 sec to 10 hr through FTP. • Node 0 sends node 11 13000 items of 512 bytes each between simulated times 15 sec to 10 hr. The inter
departure time for
each item is 3.1 sec.• Node 11 sends node 0 20000 items of 1024 bytes
each between
simulated times
28.8 sec to 10 hr.
The inter departure
time for each
item is 1.5 sec.
02000000400000060000008000000
100000001200000014000000
0 500 1000 1500 2000Simulation time (second)
No
of b
ytes
re
ceiv
ed
SAHNRDSRAODV
Simulation Result1
session duration for SAHNR
session duration for DSR
session duration for AODV
Comparing data reception rates at FTP server 11 at normal condition
Simulation Result
2
0
20000004000000
6000000
8000000
1000000012000000
14000000
0 500 1000 1500 2000
Simulation time (second)
No
of b
ytes
re
ceiv
ed
SAHNRDSRAODV
session duration for SAHNR
session duration for DSR
session duration for AODV
Comparing data reception rates at FTP server 11 when a node periodically switches off and on
Simulation Result3
Comparing load of CTRL packets in the network at normal condition
0
2000
4000
6000
8000
10000
12000
14000
0 1000 2000 3000 4000 5000
Simulation time (second)
No
of C
TR
L pa
ckte
s tr
ansm
itted
SAHNRDSRAODV
Simulation Result4
Comparing load of CTRL packets in the network when a node periodically switches off and on
0
5000
10000
15000
20000
0 1000 2000 3000 4000 5000
Simulation time (second)
No
of C
TR
L pa
cket
s tr
ansm
itted
SAHNRDSRAODV
Index4
Overview of SAHNRouting in SAHN (SAHNR)
Simulation ResultsFuture Work
Current Project StatusAcknowledgements
Future works
• Integrate all QoS metrics (bandwidth
reservation, error rate, latency) for routing• Incorporate security schemes i.e. node
authentication, encryption/decryption• Define a feasible network size & packet length• Detect non-cooperative nodes• Perform more simulations with varied network
sizes, different topologies with presence of
rouge nodes• Test SAHNR in real environment
Index5
Overview of SAHNRouting in SAHN (SAHNR)
Simulation ResultsFuture Work
Current Project StatusAcknowledgements
Current status
• Eliminated the use of Hello & Hello Reply
cycles for node authentication• Incorporated authentication scheme with route
discovery cycle• Performed more simulations with different
network topology
Current status2
Three more papers in press to be published• Routing In Suburban Ad-Hoc Networks
The 2003 International Conference on Computer Science and its Applications (ICCSA’03)
• A Hybrid QoS Routing Strategy for Suburban Ad-Hoc NetworksThe 11th IEEE International Conference on Networks (ICON’03)
• A Router Architecture To Achieve Link Rate Throughput In Suburban Ad-Hoc NetworksThe Eighth Asia-Pacific Computer Systems Architecture Conference (ACSAC’03)
Index6
Overview of SAHNRouting in SAHN (SAHNR)
Simulation ResultsFuture Work
Current Project StatusAcknowledgements
Acknowledgements
Initial definition of the SAHN architecture was carried out by Adrian Bickerstaffe, Enes
Makalic and Slavisa Garic in their computer science honours projects in 2001 at Monash
University. They also implemented the testbed. The current project builds on their excellent
work.
Part of presentation was partly done with Paul Conilione, using exclusively the abilities given to him by his Chinese Buddhist Taoist Master,
Shifu Chow Yuk Nen