A Hybrid QoS Routing Strategy for Suburban AdHoc Networks

1
A Hybrid QoS Routing Strategy for Suburban
Ad-Hoc Networks

• Muhammad Mahmudul Islam
• Ronald Pose
• Carlo Kopp
• School of Computer Science Software Engineering
• Monash University

2
Outline

• Introduction
• Overview of SAHN
• Routing in SAHN (SAHNR)
• Simulation Results
• Future Work
• Acknowledgements

3
Introduction (1/4)

• How to Connect to University's Network from Home
• Commercial Wired Services
• Direct Dial-up Services
• Internet Services
• Dial-up
• Broadband (cable modems, xDSL etc)
• Ad-Hoc Wireless Networks
• Single Hop Solutions
• 802.11b
• Multi Hop Solutions
• Nokia Roof-Top
• SAHN
• MIT Roofnet

4
Introduction (2/4)

• Limitations of commercial services
• Impose service charges
• Require costly wiring infrastructure
• Not widely available
• Provide mostly asymmetric bandwidth utilization
• Inadequate for file transfer, X protocol,
  interactive graphical programs etc

5
Introduction (3/4)

• Limitations of single hop ad-hoc networks
• Must have direct connectivity to all nodes
• Longer distances
• may be covered
• with higher
• transmission energy
• Interference may increase as connectivity
  increases
• Overall network throughput may decrease

6
Introduction (4/4)

• Limitations of Nokia RoofTop
• A central admninistrator has control over the
  whole network through RMS to
• Assign addresses to each node
• Change subscribers setting
• Unable to detect rogue/non-cooperating nodes
• Authetication scheme using 16 bit key

7
SAHN (1/2)

• Provides 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 Telco
  independent traffic
• Features multi-hop QoS routing
• 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 to avoid
  congestion
• Proper resource access control and management

8
SAHN (2/2)

• Ideal for cooperative nodes. E.g. spread over a
  suburban area, connecting houses and business
• Topology is quasi static
• Uses wireless technology
• Symmetric broadband, multi Mbps bandwidth
• No charges for SAHN traffic
• SAHN services
• run alongside
• TCP/IP
• Conceived by
• Ronald Pose
• Carlo Kopp in 1997

9
A Standard SAHN Node

• Appears to host like a cable modem
• Functionally more like a
• RF LAN repeater
• Embedded
• microprocessor
• protocol engine
• that implements all
• SAHN protocols, manages
• and configures the system
• Each SAHN node has at least 2 wireless links
• Capable of achieveing link rate throughput

10
References

• 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
• MIT Roofnet. http//www.pdos.lcs.mit.edu/roofnet/

11
Design Challenges for SAHN Routing (1/2)

• 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
• Resource management
• Requires higher level protocols to efficiently
  handle limited resources

12
Design Challenges for SAHN Routing (2/2)

• Ad-Hoc wireless networks should
• handle node/link failures
• find routes on demand
• route packets with required QoS
• detect non-cooperating nodes
• Requires an efficient on-demand routing solution

13
Possible Routing Solutions for SAHN (1/3)
14
Possible Routing Solutions for SAHN (2/3)

• Dynamic source routing (DSR)
• On demand
• Uses 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
• Cannot detect non-cooperating nodes

15
Possible Routing Solutions for SAHN (3/3)

• Ad Hoc on demand distance vector (AODV) routing
• 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
• Cannot detect non-cooperating nodes

16
Why Customized Routing for SAHN (1/2)

• Existing ad-hoc routing 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
• Handling non-cooperating nodes

17
Why Customized Routing for SAHN (2/2)

• Mobile IP (IPv6)
• Uses proactive routing technique ideal for
  centralized networks
• Whole network is flooded with link state
  information
• Assumes direct link (single hop) between
  home/foreign agent and each host
• Cannot not handle non-cooperating nodes

18
Properties of SAHN Routing Protocol (1/2)

• Uses source routing for route discovery
• Maintains routes dynamically
• similar to DSR
• e.g. gratuitous Route replies, salvaging
  data/error packets etc

19
Properties of SAHN Routing Protocol (2/2)

• 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 with least
  network overhead
• Node authentication
• Encryption of packet information
• Handling non-cooperative nodes

20
Focus of this Paper

• Modified DSR to
• decrease network overhead by
• excluding source route in every data packet
• avoid selfish/uncoordinated routing strategy by
• choosing least congested paths
• feature network level security by
• encryption of packet information
• QoS parameters for SAHNR
• Available bandwidth (bypass congested paths)
• Network level encryption for each session

21
Phases of SAHNR

• Route Discovery
• On demand
• Data Transmission
• On demand
• Route Maintenance
• Periodically and on demand

• Node Authentication
• Exchange of keys
• are done in these phases

22
Network Level Security at a Glance

• RREQ packets contain
• Public key
• ACKRREQ packets contain
• Public key
• Shared key
• Identification signature
• 1 2 are encrypted with down stream nodes
  public key
• Initial DATA packet for a session contains
• Shared key
• Identification signature
• 1 2 are encrypted with upstream nodes
  public key

from downstream nodes
from upstream nodes
from downstream nodes
23
Neighbour Discovery Security (1/8)

• Requires RREQ, ACKRREQ, RREP ACKRREP packets
• Authentication and negotiation of shared key for
  encrytion/decryption of data packet is performed

RREQ/RREP Packet Format
24
Neighbour Discovery Security (2/8)

• S wants to find route to X
• Generates public key (PbS), private key(PrS)

25
Neighbour Discovery Security (3/8)

• S broadcasts RREQS packets to its neighbours
  with PbS

26
Neighbour Discovery Security (4/8)

• B generates PbB, PrB a shared key (ShB)
• Encrypts ShB Bs identification signature with
  PbS
• Unicasts ACKRREQ with e(ShBB,PbS) PbB to S
• Rebroadcasts RREQ packets to its neighbours with
  PbB

27
Neighbour Discovery Security (5/8)

• S gets ShB Bs identification signature by
  decryption
• d(e(ShBB,PbS), PrS)
• Registers B as a valid node if its signature
  matches node identification table

28
Neighbour Discovery Security (6/8)

• H receives RREQE from E
• H has route to X

29
Neighbour Discovery Security (7/8)

• H generates a RREPH packet from RREQE RTH
• H unicasts RREPH packet to E

30
Neighbour Discovery Security (8/8)

• A RREP is forwarded according to the next node
  address
• S receives RREPs from neighbouring nodes
• S selects a suitable route based on gathered QoS
  of each route

31
Data Transmission (1/4)

• First few data packets contains full RIL
• S generates a ShS or keeps Shb
• S unicasts DATA packet with e(ShSS,PbB) to B

32
Data Transmission (2/4)

• B gets ShS Ss identification signature by
  d(e(ShSS,PbB), PrB)
• Registers S as a valid node matching its node
  identification table
• Updates RT/FT with unknown information
• Forwards data packet to the next node from RIL
  with e(ShBB,PbC)

33
Data Transmission (3/4)

• Reamining nodes registers immediate upstream
  nodes
• Update RT/FT with unknown information
• Forward data packet to the next node from RIL
  with e(Sh??,Pb?)

34
Data Transmission (4/4)

• Remaining data packets do not contain RIL
• An intermediate node
• Finds the next node from the FT with ltGlobal
  Source, Global Destinationgt
• Updates Local Source with its own address
• Updates its RT/FT

DATA Packet Format
35
Route Maintenance (1/4)

• Takes actions if
• A link fails
• A route error control (RERR) packet is received
• Data packets are recieved for unknown
  destinations
• A RT/FT entry becomes too old

RERR Packet Format
36
Route Maintenance (2/4)

• 1. If the route maintenace module senses a link
  failure
• Tries to find alternate route to destination
• Sends RERR of the broken link to its neigbours
• Deletes corresponding entries of broken links
  from its RT/FT

37
Route Maintenance (3/4)

• 2. If a node receives a RERR packet the
  route maintenance module
• Sends RERR to its neigbours
• Deletes corresponding entries from its RT/FT

38
Route Maintenance (4/4)

• 3a. If a node receives a data packet for unknown
  destination, the route maintenance module
• Tries to find a route to the destination
• 3b. If it fails, it
• Sends RERR to the source of the data packet

39
References

• 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/a
  dhoc_routing/index.html. 02/07/2000

40
Simulation Setup (1/2)

• GloMoSim (version 2.03)
• 21 static nodes in 3 sq. km physical terrain
• Standard radio model for transmission
• Propagation limit -111.0 dBm
• Two-Ray model for the propagation path loss where
• Free space path loss for direct links
• Plane earth path loss for more distant links
• Radio transmission power 15.0 dBm, antenna gain
  0.0 dB, radio reception threshold -81.0 dBm,
  sensitivity -91.0 dBm SNR 10.0 dB
• AODV, DSR and SAHNR were used as routing
  protocols
• SAHNR contaied follwoing features
• All standard features of DSR
• Network level shared key negotiation
• Accumulation of QoS info (available bandwidth)
  during route discovery
• Route selection based on bandwidth availabilty
  hop count
• Using forward table for data transmission

41
Simulation Setup (1/2)

• FTP connection. 0 (Client), 11 (Server)
• Total 8000000 pkts, 1460 bytes/ pkt, starts at
  30 sec sim time
• FTP connection. 19 (Client), 1 (Server)
• Total 11000 pkts, 1400 bytes/ pkt,
• starts at 70 sec sim time
• FTP connection. 18 (Client), 3 (Server)
• Total 9000000 pkts, 1500 bytes/pkt,
• starts at 100 sec sim time
• CBR connection. 0 (Client), 20 (Server)
• Total 13000000 pkts, 1512 bytes/pkt,
• inter-departure time 1.5 sec/pkt,
• starts at 28.8 sec sim time
• CBR connection. 17 (Client), 0 (Server)
• Total 20000000 pkt, 1024 bytes/pkt,
• inter-departure time 1.1 sec/pkt,
• starts at 15 sec sim time

42
Simulation Result (1/3)
Comparing total data received at FTP servers
using SAHNR, DSR and AODV
43
Simulation Result (2/3)
Comparing load of CTRL packets in the network
44
Simulation Result (3/3)
Comparing number of packets received with and
without source routes with SAHNR
WSR - With Source Route WOSR- Without Source Route
WSR
WOSR
45
Future works

• Integrate all QoS metrics (bandwidth, error rate,
  latency, jitter) 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, directional antennas and different
  topologies with presence of rouge nodes
• Test SAHNR in real environment

46
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 initial 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.

47
Thank You

• ?