Reactive Routing Protocols for Ad hoc Mobile Wireless Networks

1
Reactive Routing Protocols for Ad hoc Mobile
Wireless Networks

• Wireless Network Seminar
• Emad Felemban

2
Overview
Ad Hoc Routing Protocols
Reactive
Proactive
Demand-Driven
Table-Driven
WRP
DSDV
AODV
DSR
LMR
ABR
CGSR
SSR
TORA
Elizabeth Royer and Chai Keong Toh, A review of
Current Routing Protocols for Ah Hoc Mobile
Wireless Networks, IEEE personal Communications
April 1999
3
Proactive vs Reactive
Proactive Reactive
Route from each node to every other node in the network Routes from Source to Destination only
Routes are ready to use instantaneously Routes constructed when needed, higher connection setup delay
Periodic route-update packets Route update when necessary
Large routing tables Small or No routing tables
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On-Demand Routing Protocols
Hop-by-Hop Routing
Source Routing
ABR
DSR
AODV
LAR
LMR
RDMAR
SSA
TORA
Elizabeth Royer and Chai Keong Toh, A review of
Current Routing Protocols for Ah Hoc Mobile
Wireless Networks, IEEE personal Communications
April 1999
5
Source Routing vs Hop-by-Hop Routing
Source Routing Hop-By-Hop Routing
Data packets carry the complete addresses from source to destination Data packets carry the address of the destination and the next hop
No routing table in intermediate nodes All nodes maintain localized routing tables
Not Scalable Scalable
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General Properties

• Loop Free Routing
• Two Operation Phases
• Route Establishment
• Route Request ? RouteRequest Packet, flooded by
  the Source node
• Route Reply ? RouteReply Packet, returned to
  source node by Destination or Intermediate node
• Route Maintenance
• Route Reconstruction
• Route Deletion

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Protocols

• DSR Dynamic Source Routing
• ABR Associativity-Based Routing
• SSA Signal Stability-Based Adaptive Routing
  Algorithm
• AODV Ad Hoc On-Demand Distance Vector
• LAR Location Aided Routing Protocol
• RDMAR Relative Distance Micro-Discovery Ad Hoc
  Routing
• LMR Light-weight Mobile Routing
• TORA Temporally Ordered Routing Algorithm
• ARA Ant-colony-based Routing Algorithm

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On-Demand Routing Protocols
Hop-by-Hop Routing
Source Routing
ABR
DSR
AODV
LAR
LMR
RDMAR
SSA
TORA
Elizabeth Royer and Chai Keong Toh, A review of
Current Routing Protocols for Ah Hoc Mobile
Wireless Networks, IEEE personal Communications
April 1999
9
Dynamic Source Routing (DSR)

• Full source-route is aggregated in RouteRequest,
  and sent back in RouteReply
• Each data packet carry the full address for all
  nodes along the path
• Can store Multiple routes to destination
• Good for Small/ Low mobility networks

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DSR Route Discovery

• Source Node broadcast RouteRequest packet
• Each Intermediate node do the following steps
• If request received before ? discard
• If node ID is listed in request ? discard
• If Route to the destination is available? send
  RouteReply to the source node with full path
• Otherwise ? append node ID and rebroadcast
• When destination is reached ? return RouteReply
  with full path
• Intermediate nodes cache all paths they overhear
• Source node caches all paths received and choose
  Shortest Path

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DSR - Route Request
S-B
S-B-E
E
B
S
D
S-B-C
C
S-B
S
S-A-G-F
F
S-B-C
S
A
G
S-A-G
S-A
RouteRequest Dropped
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DSR - Route Reply
B-E-D
E-D
S-B-E-D
S-B-E-D
E
B
S-B-E-D
D
C
S
S-B-E-D
S-A-G-F-D

S-A-G-F-D
F
F-D
A
S-A-G-F-D
S-A-G-F-D
G
A-G-F-D
S-A-G-F-D
G-F-D
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DSR Route Maintenance

• Triggered when a link breaks between two nodes
  along the path from the Source to the destination
• Node who discover the break send a RouteError to
  inform the source node about the broken link
• Source Node
• erase the route from the cache, and
• Use another cached routes, Or
• Request a new Route

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DSR Route Maintenance
RouteError
E
B
RouteError
D
C
S
S-B-E-D
S-A-G-F-D

F
A
G
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DSR

• Promiscuous mode, intermediate nodes learns about
  routes breaks
• During network partition, if the destination is
  in different partition a backoff algorithm is
  used to prevent frequent RouteRequest broadcast

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DSR -- Concerns

• Scalability
• Large overhead in each data packet
• No Local repair of the broken link
• Stale cache information could result to
  inconsistence during route reconstruction
• Poor Performance as Mobility increases

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Associativity-Based Routing (ABR)

• Select Longer-Lived routes
• Beacon based protocol
• Defining the Location Stability between nodes
• Used as a metric instead of shortest hop
• Determined by beacon counting
• Links between nodes classified into Stable and
  Unstable link according to beacons counts

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ABR Route Discovery

• Source Node broadcast RouteRequest packet
• Each intermediate node do the following steps
• If request received before ? discard
• If node ID is listed in request ? discard
• If route to the destination is available ? send
  RouteReply
• Otherwise ? append node ID and Beacon Count and
  rebroadcast

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ABR Route Discovery

• Destination node
• Once get the first RouteRequest, it waits for
  certain period to receive multiple RouteRequests
• From multiple routes, it selects the route with
  maximum proportion of stable links
• If more than one route has the maximum proportion
  of stable links, the shortest path is selected
• Only single route is selected by the destination

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ABR - Route Request
S-B
S-B-E
E
B
S-B-E-D
S-B-C-F-D
S
D
C
S-B
S-B-C
S
S-B-C-F
F
S-B-C
S
A
G
S-A-G
RouteRequest Dropped
S-A
Unstable Link
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ABR - Route Reply
E
B
S-B-C-F-D
D
C
S
S-B-C-F-D


S-B-C-F-D
F
A
G
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ABR Route Maintenance

• Try to bypass the broken link without flooding
  the RouteRequest globally
• Downstream node, sends RouteError to the
  destination, deleting cache entries along the
  path
• Upstream node broadcasts a RouteRepair with
  limited time to live
• If failed, next upstream node broadcast
  RouteRepair
• Is successful, new route is used
• If the process traverse near source node, a new
  RouteRequest is initiated

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ABR Concerns

• Chosen path may not be shortest path
• May lead to higher delay in route repairs
• Single path selection
• High cost of periodic beaconing
• Power
• Bandwidth

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Signal Stability-based adaptive routing algorithm
(SSA)

• Derivative of ABR
• Adds Signal Strength as a prime metric
• In addition to beacon count, each node keep
  record of the signal strength of other neighbors
• Links are classified as Strong/Stable links vs
  Weak/unstable links

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SSA Route Discovery

• RouteRequests are forwarded through strong/stable
  links only
• RouteRequest received through weak/unstable links
  are dropped
• Failed RouteRequest ? flood route discovery
  without Signal strength metric
• Destination node,once get the first RouteRequest
  over stable links, it sends RouteReply

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SSA - Route Request
S-B
S-B-C-E
E
B
S
D
S-B-C-F-D
S-B-C
C
S-B
S
S-B-C-F
F
S-B-C
S
A
G
S-A-G
S-A
RouteRequest Dropped
Unstable Link
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SSA - Route Reply
E
B
D
C
S
S-B-C-F-D
S-B-C-F-D
F
A
G
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SSR Route Maintenance

• End nodes of the broken links notify source and
  destination
• Erasing cache entries along the path
• Source broadcast a new RouteRequest to find
  Stable link

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SSA Concerns

• Restrict condition on forwarding RouteRequest ?
  large setup time in case no stable links are
  found

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On-Demand Routing Protocols
Hop-by-Hop Routing
Source Routing
ABR
DSR
AODV
LAR
LMR
RDMAR
SSA
TORA
Elizabeth Royer and Chai Keong Toh, A review of
Current Routing Protocols for Ah Hoc Mobile
Wireless Networks, IEEE personal Communications
April 1999
31
Ad Hoc On-Demand Distance Vector Routing (AODV)

• Source Routing (DSR, ABR and SSA) is good for
  smaller networks due to large data packet
  overhead
• AODV
• Hop by Hop basis
• No need to include the full path in the data
  packet
• Update Neighborhood information through periodic
  beacons

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AODV Route Discovery

• Source Node broadcast RouteRequest packet
• Each intermediate node gets a RouteRequest do the
  following steps
• Establish a reverse link to node it received the
  RouteRequest from
• If request received before ? discard
• If route to destination is available and
  up-to-date ? return RouteReply using the reverse
  link
• Otherwise ? rebroadcast the RouteRequest
• Destination node respond with RouteReply using
  the reverse link

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AODV - Route Discovery
E
B
D
C
S
F
A
G
RouteRequest
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AODV - Route Discovery
E
B
D
C
S
F
A
G
Reverse Path Setup
RouteRequest
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AODV - Route Discovery
E
B
D
C
S
F
A
G
RouteRequest Dropped
Reverse Path Setup
RouteRequest
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AODV - Route Discovery
E
B
D
C
S
F
A
G
RouteReply
Reverse Path Setup
RouteRequest
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AODV - Route Discovery
E
B
D
C
S
F
A
G
Forward Route Setup
RouteReply
Reverse Path Setup
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AODV - Route Discovery
E
B
D
C
S
F
A
G
Forward Route Setup
RouteReply
Reverse Path Setup
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AODV - Route Discovery
E
B
D
C
S
F
A
G
Forward Route Setup
RouteReply
Reverse Path Setup
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AODV Route Maintenance

• When a node detects a link failure, it sends
  special RouteReply with infinity distance
• RouteReply is propagated to source node
• Source node initiates a new RouteRequest

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AODV Route Maintenance
RouteReply
E
B
RouteReply
D
C
S
F
A
G
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AODV Concerns

• Route Reply from intermediate nodes can lead to
  inconstant routes ? Stale Cache
• Periodic beaconing cost

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Location Aided Routing (LAR)

• Reduce the routing overhead in the network
• Source node flood the request to certain area
  where it last heard from the destination
• For the first time, it uses normal flood
  mechanism? broadcast to all locations
• GPS is required

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LAR

• Expected Zone The region that may contain the
  destination based on its previous location, speed
  and time.
• Request Zone The region that RouteRequest packet
  are allowed to propagate to reach the destination

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LAR

• Two Scheme
• Flood the RouteRequest into the request zone only
  to reach the destination in the expected zone
• Stores the coordinates in the route request
  packets, the packets can only travel in the
  direction where the relative distance to the
  destination becomes smaller

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LAR

• Destination once receive RouteRequest from the
  source, it sends RouteReply with its location and
  time stamp

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Relative Distance Micro-Discovery ad hoc
routing(RDMAR)

• Reduce the routing overhead in the network
• Minimize the flooding effect by limiting route
  request to certain number of hops
• Used in Route Construction and Maintenance
• No need for GPS
• At the first time it works like normal flooding
  operation? Route discovery will have global
  effect

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Light Wight Mobile Routing (LMR)

• Destination rooted Directed Acyclic Graph ? Based
  of link reversals protocol
• Multiple route to the destination
• no need to initiate another RouteRequest unless
  all routes failed
• Less Overhead
• Good for routing in moderate mobile network

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LMR Route Discovery

• Every node is aware of its neighbors
• Once RouteRequest received by one of the
  destinstion neighbors it sends RouteReply
• As the RouteReply packet traverse back to the
  source node, DAG is constructed

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LMR - Route Request
E
B
D
C
S
F
A
G
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LMR - Route Reply
E
B
D
C
S
F
A
G

• As the RouteReply Packet traverse to the source
  the unsigned links become directed towards the
  destination
• S has many routes to D

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LMR Route Maintenance

• Triggered, when the last route to the destination
  is lost
• Node around the broken links inform its upstream
  neighbor using RouteError packet
• The packet informs the neighbors that no valid
  route exists anymore through the node to the
  destination
• If the upstream neighbor has a route to the
  destination it sends Routeply packet, the links
  adjusted

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LMR - Route Maintenance
E
B
D
C
S
F
A
G
Route Error
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LMR - Route Maintenance
E
B
D
C
S
F
A
G
Route Reply
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LMR Concerns

• Unlimited time to recover from network
  partitioning ? proposal for TORA

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Temporally Ordered Routing Algorithm (TORA)

• Like LMR based on Link Reversal Algorithms
• Solve LMR problem in case of Network partitions
  by limiting the route maintenance packets to a
  small region
• Adopt the height metrics
• Requires time synchronization

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TORA Route Discovery

• Source broadcast RouteRequest to the destination
• Destination sets it height to zero and transmit
  an RouteReply packet
• Each node along the way to the source increase
  its height by one and rebroadcasts the RouteReply
  Packet with its updated heights

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TORA - Route Request
E
B
D
C
S
F
A
G
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TORA - Route Reply
Height 1
Height 2
E
B
Height 0
D
Height 3
C
S
F
Height 2
Height 1
A
G
Height 3
Height 2
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TORA Route Maintenance

• Triggered when the last link towards the
  destination is lost
• Adjust Height Level and propagate through the
  network
• Links are reversed to reflect the change
• Route Deletion is flooded to delete invalid
  routes

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Ant Colony Based Routing Protocols (ARA)

• Adopt natural example
• When ants look for food, they leave transient
  trail on the path for others to follow
• Forwarding ANT (RouteRequest) calculates a
  pheromone value at each hop
• Once destination is reached, Backward ANT
  (RouteReply) traverse back to the source
• Data packet traverse along the path increase
  pheromone value
• Pheromone value of other unused path will
  decrease until path is expired

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Comparison
Protocol Routes Route Selection Beacon
DSR Multiple Shortest Path No
ARB Single Link Stability Yes
SSA Single Signal Strength Yes
AODV Single Shortest Path, Freshness Yes
LAR Multiple Shortest Path No
RDMAR Single Shortest Path No
LMR-TORA Multiple Link reversal No
ARA Multiple Shortest Path No
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Comparison
Protocol Maintenance Special Needs Route Discovery
DSR Global, notify source Global
ARB Local, bypass broken link Global
SSA Global, notify source Global
AODV Global, notify source Global
LAR Global, notify source GPS Localized
RDMAR Global, notify source Localized
LMR-TORA Link reversal Time Sync Global
ARA Back track until route is found Global
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Further Readings
Protocols Papers

• DSR D. B. Johnson and D. A. Maltz, Dynamic
  Source Routing in Ad-Hoc Wireless Networks,
  Mobile Computing, 1996, pp. 15381.
• AODV C. Perkins and E.M. Boyer Ad Hoc On Demand
  Distance Vector (AODV) algorithm proceedings of
  the 2nd IEEE workshop on Mobile Computing Systems
  and Applications New Orleans Louisiana, February
  1999
• ABR C-K. Toh, A Novel Distributed Routing
  Protocol To Support Ad-Hoc Mobile Computing,
  Proc. 1996 IEEE 15th Annual Intl. Phoenix Conf.
  Comp. and Commun., Mar. 1996, pp. 48086.
• SSR R. Dube et al., Signal Stability based
  Adaptive Routing (SSA) for Ad-Hoc Mobile
  Networks, IEEE Pers. Commun., Feb. 1997, pp.
  3645.
• LMR M. S. Corson and A. Ephremides, A
  Distributed Routing Algorithm for Mobile Wireless
  Networks, ACM/Baltzer Wireless Networks J., vol.
  1,no. 1, Feb. 1995, pp. 6181.
• TORA V. D. Park and M. S. Corson, A Highly
  Adaptive Distributed Routing Algorithm for Mobile
  Wireless Networks, Proc. INFOCOM 97, Apr. 1997.
• RDMAR G. Aggelou, R. Tafazolli, RDMAR a
  bandwidth-efficient routing protocol for mobile
  ad hoc networks, in ACM International Workshop
  on Wireless Mobile Multimedia
• (WoWMoM), 1999, pp. 2633.
• LAR Y.-B. Ko, N.H. Vaidya, Location-aided routing
  (LAR) in mobile ad hoc networks, in Proceedings
  of the Fourth Annual ACM/IEEE International
  Conference on Mobile Computing and Networking
  (Mobicom98), Dallas, TX,1998.
• ARA M. Gunes, U. Sorges, I. Bouazizi, Arathe
  ant-colony based routing algorithm for manets,
  in ICPP workshop on Ad Hoc Networks (IWAHN
  2002), August 2002, pp. 7985.

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Further Readings
Survey Papers

• Mehran Abolhasan et al, A review of routing
  protocols for mobile ad hoc networks Ad Hoc
  Networks 2004 (1-22)
• Laura M. Feeney, A Taxonomy for Routing
  Protocols in Mobile Ad Hoc Networks, Technical
  Report
• Avinash Kasyyap et al, Survey on Unicast Routing
  in Mobile Ad Hoc Networks,2001
• E. Boyer and C. Toh, A review of current routing
  protocols for Ah Hoc Mobile Wireless Networks,
  IEEE personal Communications, April 1999.