GeoCast

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GeoCast thesis report

• By Chiang Jui-Hao

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Preface

• GeoCast
• Thesis report
• Simulation progress

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GeoCast - Geographic Addressing and Routing
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GeoCast

• Widely using GPS
• Direction giving
• Navigation, etc
• New routing and addressing method
• In the past logical addressing
• Now physical addressing (geographical
  addressing)
• New services and functionalities
• Come from location services

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Possible new services and functionalities

• Geographic messaging
• Sending a message to a specific sub area
• Ex sending emergency message to everyone who is
  currently in a specific building
• Geographic advertising and Geographic services
• Server (fixed or mobile) providing services
• Advertising only to the neighboring area
• Pervasive computing?

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Possible new services and functionalities (cont.)

• Who is around service
• Finding out who is currently in a specific region
• To support these services
• Changes from IP level to application level
• Sending message not only to a single host, but
  any arbitrary polygon

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Addressing Model

• 2-dimensional GPS positioning provides
• ltlatitude, longitudegt
• longitude -180(west) 180(east)
• latitude -90(south) 90(north)
• lt40.48640, -74.44513gt ? town of New Brunswick,
  New Jersey, U.S.A.
• 8 bytes address
• Precision to surface of earth is 0.1 mile

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Using a Geographic Destination Address

• Geographic destination
• Point
• Circle (center point, radius)
• Polygon (point(1), point(2), , point(n-1),
  point(n), point(1))

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Routing geographically

• 3 methods for achieving geographically-routed
  messages
• Geographically-aware router
• Multicast solution
• Domain Name Service solution
• Chose geographically-aware router solution
• Multicast is not stable now
• Use polygonal geographic destination address

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Routing geographically (cont.)

• Implementing it in application level
• Use IP tunnels
• Transport data from these router through areas
  which do not support geographic routing

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Components of this routing
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GeoRouter

• Moving a message from a sender to a receiver
• Capabilities
• Basic multi-hop geographic routing
• Automatic detection of multiple network interface
• Type of network interface (wired or wireless)
• Other GeoRouters
• Base station GeoNode programs

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GeoRouter (cont.)

• Automatic configuration of routing tables
• Based on detected information
• Manually configurable to do hierarchical network
  routing

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GeoNode

• An entry/exit
• for the routing system
• Receive incoming geographic messages
• Store duration of lifetime
• Periodically multicast those messages
• To all of the subnets or
• Wireless cells
• Each subnet and each wireless cell
• At most one GeoNode

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GeoNode (cont.)

• Message lifetime
• Set by sender
• Is necessary for mobility
• If there are several geographic messages
• Will be scheduled
• Considering
• Message size
• Priority of message
• Speed of subnets transport medium

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GeoHost

• Is a daemon
• Located on all computer hosts, which are capable
  of receiving and sending these messages
• Its job is to notify all client processes
• Availability of geographic messages
• Current location of the host
• Address of local GeoNode

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Routing -- overview

• Sending geographic messages (3 parts)
• Sending the message (1)
• GeoHost will remember the IP address of its own
  host
• GeoHost -gt GeoNode -gt GeoRouter
• Passing the message between routers (2)
• Check the service polygon of GeoRouter
• Check if it and destinations polygon intersect
• If not, sends to parent router

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Routing (cont.)

• If it does match
• If Match partially
• sends to part of target area
• sends a copy to parents node (further
  forwarding)
• Test childs service area to forwarding

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Routing (cont.)

• Receiving geographic messages (3)
• GeoRouter ? GeoNode
• GeoNode store it locally
• Assigned a multicast group to it
• Remember this source node is available
• GeoNode will Periodically multicast
• The list of available messages on a well-known
  group address (tell unknown people)
• The message on its assigned multicast group

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Routing packet header
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Different shapes of destination polygon
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Simulation results
Test-1 destination is variable Cell-2 GeoNode
is variable
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Thesis progress
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Summary

• Broadcasting location information based on some
  function of mobility
• If A wants to transmit packet to B
• Find path from its own topology
• Add route to packet header like source routing
• If no routing path to use
• Drop the packet ? or
• flooding to route request ?

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Three strategies

• Restricted range flooding
• Moving effect
• Mobility prediction

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Restricted range flooding

• Restrict the transmission range of location
  update packet
• Minimize the traffic due to dissemination
• Transmission range must reflect the mobility
  characteristic of each mobile node
• Concerning about the distance effect
• The emergency range must be in the moving
  direction of each node

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Moving effect
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Mobility prediction (scenario)
?
??
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Mobility prediction (cont.)

• Assume location packet transfer from node A to
  node B
• Node A moved quickly after send the message
• B receive the wrong position (and then
  rebroadcast it)
• So, node B can predict As activity
• By comparing position in current packet and that
  in its own cache
• Then rebroadcast the estimated position of A

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Simulation progress
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Ns architecture
TclObject
Handler
NsObject
Connector
Classifier
Delay
AddrClassifier
Agent
McastClasifier
Queue
Trace
DropTail
RED
TCP
Enq
Deq
Drop
Reno
SACK
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Simulation architecture
Agent (CBR)
CBR
Location
Routing (DSR)
Routing (DSR)
broadcast
Link Layer
Link Layer
PHY
PHY
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Current progress

• Finished
• Writing a new Agent
• Forming a new packet format
• Broadcasting location information
• Not finished
• Rewrite DSR

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