QoS Routing in Ad Hoc Networks --Literature Survey

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QoS Routing in Ad Hoc Networks--Literature
Survey

• Presented by Li Cheng
• Supervisor Prof. Gregor v. Bochmann

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Outline

• QoS routing overview targets and challenges
• Classification of QoS routing protocols
• Typical QoS routing protocols
• Conclusion and Open Issues

Video frame without QoS Support
Video frame with QoS Support
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Features of MANET

• Mobile Ad-hoc Network
• Definition a self-configuring network of mobile
  routers (and associated hosts) connected by
  wireless linksthe union of which form an
  arbitrary topology (www.wikipedia.org)
• Features
• Dynamic and frequently changed topology
• Self-organizing
• Nodes behaving as routers
• Minimal configuration and quick deployment
• Limited resources

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Ad Hoc vs. Cellular Networks

• Multi-hop route vs. One-hop route
• In an Ad Hoc network, every nodes has to behave
  as a router
• Self-administration vs. Centralized
  Administration
• Ad hoc networks are self-creating,
  self-organizing, and self-administering

OMC
AC
BSC
BTS
PSTN
MSC
BSC
BTS
VLR
BSC
MS
Ad Hoc wireless network
BTS
Cellular wireless network
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Target of QoS Routing

• To find a feasible path between source and
  destination, which
• satisfies the QoS requirements for each admitted
  connection and
• Optimizes the use of network resources

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lt4,5gt
B
C
A
lt4,2gt
lt5,3gt
lt2,4gt
Tuple ltBW,Dgt QoS requirement BW4
lt3,4gt
E
F
lt3,3gt
D
lt2,2gt
lt4,4gt
Shortest path
G
QoS Satisfying path
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Challenges of QoS Routing in Ad Hoc Networks

• Dynamic varying network topology
• Imprecise state information
• Scare resources
• Absence of communication infrastructure
• Lack of centralized control
• Power limitations
• Heterogeneous nodes and networks
• Error-prone shared radio channel
• Hidden terminal problem
• Insecure medium
• Other layers

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Criteria of QoS Routing Classification

• Routing information update mechanism
• Proactive/table-driven QOLSR, EAR
• Reactive/On-demand QoSAODV, PLBQR, TBP
• Hybrid CEDAR
• Use of information for routing
• Information of past history QOLSR, QoSAODV, TBP
• Prediction PLBQR
• State maintenance
• Local PLBQR, CEDAR
• Global TDMA_AODV, TBP
• Routing topology
• Flat QOLSR, QoSAODV, PLBQR, TBP
• Hierarchical CEDAR
• Interaction with MAC layers
• Independent PLBQR, QoSAODV, TBP
• Dependent CEDAR, PAR
• Number of Path Discovered
• Single path QoSAODV, CEDAR, PLBQR
• Multiple paths TDMA_AODV, TBP

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Typical Routing Mechanism

• Proactive routing QOLSR
• Reactive routing QoSAODV
• Ticket-based Routing TBP
• Hierarchical Routing CEDAR
• Predictive Location-based routing PLQBR
• Power aware routing

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Proactive QoS Routing QOLSR

• Optimized Link State RoutingRFC3626
• Aiming at large and dense MANETs with lower
  mobility
• Only selected nodes as multi-point relays (MPRs)
  forwards broadcasting messages to reduce overhead
  of flooding
• MPR nodes periodically broadcast its selector
  list
• QoS extensions
• QOLSRIETF Draft Hello messages and routing
  tables are extended with parameters of maximum
  delay and minimum bandwidth, and maybe more QoS
  parameters
• Advantage ease of integration
• in Internet infrastructure
• Disadvantages Overhead to keep
• tables up to date

Black nodes MPRs
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Reactive QoS Routing QoS Enabled AODV

• AODV Ad-hoc On-demand Distance Vector
  routingRFC3561
• Best effort routing protocol
• On need of a route, source node broadcasts route
  request(RREQ) packet
• Destination, or an intermediate node with valid
  route to destination, responses with a route
  reply(RREP) packet.
• QoS extensionsIETF Draft maximum delay and
  minimum bandwidth are appended in RREQ, RREP and
  routing table entry
• Disadvantages
• No resource reservation, which unable to
  guarantee QoS
• Improved with bandwidth reservation TDMA_AODV7
  
• Traversal time is only part of delay

RREQ1 (delay100)
RREQ1 (delay70)
RREQ1 (delay20)
Delay(C-gtD)50
RREP1 (delay80)
RREP1 (delay0)
RREP1 (delay50)
QAODV example Delay Requirement
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Ticket-based Probing5 Features

• Objective To find delay/bandwidth-constrained
  least-cost paths
• Source-initiated path discovery, with limited
  tickets in probe packets to decrease overhead
• Based on imprecise end-to-end state information
• QoS metrics Delay and bandwidth
• Redundancy routes for fault tolerance during path
  break
• Destination initiated Resource Reservation

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Tickets-relative Issues

• Colored tickets yellow ones for smallest delay
  paths, green ones for least cost paths
• For source node, how many tickets shall be
  issued?
• more tickets are issued for the connections with
  tighter or higher requirements
• For intermediate nodes, how to distribute and
  forward tickets?
• the link with less delay or cost gets more
  tickets
• How to dynamically maintain the multiple paths?
• the techniques of re-routing, path redundancy,
  and path repairing are used

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Disadvantages and Enhancement of TBP

• Enhanced TBP Algorithm13
• Color-based ticket Distribution
• Ticket optimization using historical probing
  results
• Disadvantages
• Based on assumption of relatively stable
  topologies
• Global state information maintenance with
  distance vector protocol incurs huge control
  overhead
• Queuing delay and processing delay of nodes are
  not taken into consideration

Ticket blocking
Color-based ticket distribution
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Hierarchical Routing CEDAR6

• Core Extraction Distributed Ad Hoc Routing
• Oriented to small and middle size networks
• Core extraction A set of nodes is
  distributivedly and dynamically selected to form
  the core, which maintains local topology and
  performs route calculations
• Link state propagation propagating bandwidth
  availability information of stable high bandwidth
  links to all core nodes, while information of
  dynamic links or low bandwidth is kept local
• QoS Route Computation
• A core path is established first from dominator
  (neighboring core node) of source to dominator of
  destination
• Using up-to-date local topology, dominator of
  source finds a path satisfying the requested QoS
  from source to furthest possible core node
• This furthest core node then becomes the source
  of next iteration.
• The above process repeats until destination is
  reached or the computation fails to find a
  feasible path.

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CEDAR routing example
G
A
Core Node Links that node B aware of

H
D
B
C
E
F
K
S
J
Node S informs dominator B
G
A
H
D
B
C
E
F
Links that node E aware of
Partial Route constructed by B
S
K
J
G
A

• Disadvantages of CEDAR
• Sub-optimal route
• Core nodes being bottleneck

H
D
B
C
E
F
S
K
J
Complete, with last 2 nodes determined by E
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Predictive Location-based QoS Routing PLBQR8

• Motivation to predict a future physical location
  based on previous location updates, which in turn
  to predict future routes
• Update protocol each node broadcasts its
  geographical update and resource information
  periodically and in case of considerable change
• Location and delay prediction
• Using similarity of triangles and
• Pythagoras theorem,
• (xp,yp) can be calculated
• End-to-end delay from S to D
• is predicted to be same as delay of latest
  update from D to S
• QoS routing
• Neighbor discovery with location-delay prediction
• Depth-first search to find candidate routes
  satisfied QoS requirements
• Geographically shortest route is chosen
• Route is contained in data packets sent by source
• Disadvantages
• No resource reservation
• Inaccuracy in delay prediction

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Power-aware QoS Routing

• Objective
• to evenly distribute power consumption of each
  node
• to minimize overall transmission power for each
  connection
• to maximize the lifetime of all nodes
• Power-Aware Routing9 using power-aware metrics
  in shortest-cost routing
• Minimize cost per packet, with cost as functions
  of remaining battery power
• Minimize max node cost of the path to delay node
  failure
• Maximum battery life routing10 Conditional
  Max-Min Battery Capacity Routing (CMMBCR)
• To choose shortest path if nodes in possible
  routes have sufficient battery
• Avoiding routes going though nodes whose battery
  capacity is below threshold
• Energy Aware Routing11 selecting path
  according to its probability, which is inversely
  proportional to energy consumption, using
  sub-optimal paths to increase network
  survivability

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Conclusion

• QoS routing is key issue in provision of QoS in
  Ad Hoc networks
• Number of QoS routing approaches have been
  proposed in literature, focusing on different QoS
  metrics
• No particular protocol provides overall solution
• Some Open Issues
• QoS metric selection and cost function design
• Multi-class traffic
• Scheduling mechanism at source
• Packet prioritization for control messages
• QoS routing that allows preemption
• Integration/coordination with MAC layer
• Heterogeneous networks

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Primary References

• 1 T.Clausen, P.Jacquet, Optimized Link State
  Routing Protocol(OLSR), IETF RFC3626, Oct.2993.
• 2 H.Badis, K.Agha, Quality of Service for Ad
  hoc Optimized Link State Routing Protocol
  (QOLSR), IETF Draft, Oct.2005
• 3 C.Perkins, E. Royer and S. Das, Ad hoc
  On-Demand Distance Vector (AODV) Routing, IETF
  RFC3561, Oct.2993.
• 4 C.Perkins, E. Royer and S. Das, Quality of
  Service for Ad hoc On-Demand Distance Vector
  Routing, IETF Draft, Jul.2000.
• 5 S.Chen,K.Nahrstedt, Distributed
  Quality-of-Service Routing in Ad Hoc Network,
  IEEE Journal on Selected Areas in Commun, Aug
  1999.
• 6 R.Sivakumar, P.Sinda and V. Bharghavan,
  CEDAR A Core-Extraction Distributed Ad Hoc
  Routing Algorithm, IEEE Journal on Selected Areas
  in Commun, Aug 1999.
• 7 C.Zhu, M.Corson, QoS routing for mobile ad
  hoc networks, IEEE Infocom 2002.
• 8 S.Shah, K.Nahrstedt, Predictive
  Location-Based QoS Routing in Ad Hoc Networks,
  IEEE ICC 2002.
• 9 S. Singh, M.Woo and C.Raghavendra,
  Power-aware Routing in Mobile Ad Hoc Networks,
  MOBICOM98.
• 10 C. Toh, Maximum Battery Life Routing to
  Support Ubiquitous Mobile Computing in Wireless
  Ad Hoc Networks, IEEE commun, Magazine, Jun 2001.
• 11 R Shah, J.Rabaey, Energy Aware Routing for
  Low Energy Ad Hoc Sensor Networks, IEEE WCNC
  2002.

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Secondary References

• 12 S.Chen,K.Nahrstedt, Distributed QoS Routing
  with Imprecise State Information, IEEE ICCCN98.
• 13 L.Xiao,J.Wang and K.Nahrstedt, The Enhanced
  Ticket-based Routing Algorithm, IEEE ICC, 2002
• 14 C.Murthy, B.Manoj, Ad Hoc Wireless Networks,
  Pentice Hall, 2004
• 15 M.Ilyas, I.Mahgoub, Mobile Computing
  Handbook, Auerbach Publications, 2005
• 16 S.Chakrabarti, A.Mishra, QoS Issues in Ad
  Hoc Wireless Networks, IEEE Commun. Magzine, Feb.
  2001

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Thanks for your time
Any Questions?