Remo Cocco, Malik Ahmed, Dan Urbano, and Vasil Hnatyshin Department of Computer Science Rowan...
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Transcript of Remo Cocco, Malik Ahmed, Dan Urbano, and Vasil Hnatyshin Department of Computer Science Rowan...
Remo Cocco, Malik Ahmed, Dan Urbano, and Vasil HnatyshinDepartment of Computer ScienceRowan University
AODV ROUTING
Topics
Routing – An Overview Forwarding Table
Mobile Networks Some Semantics Reactive vs Proactive
AODV Routing Routing Table RREQ and RREP
Location-Aided Routing
But first…
We would like to congratulate Dr. VH He will be honored in the Ki Delta’s Pi
International Honor Society 100th anniversary book
It features stories about teachers who have inspired students
The story will be read on March 8th at KDP’s Founder’s Day celebration
Topics
Routing – An Overview Forwarding Table
Mobile Networks Some Semantics Reactive vs Proactive
AODV Routing Routing Table RREQ and RREP
Location-Aided Routing
Routing – An Overview
What’s the problem? The Source Node (S) wants to send
information to the Destination Node (D). Where does S send its packets of information
to in order for the packets to end up at D?
R2
S
R4
R3
R1
D
Routing – An Overview
Solution – Keep a forwarding table Source Node S keeps information about where
to send the packets to so that they end up at Destination D.
Node S looks up this information inside its forwarding table when it is about to send out packets.
R2
S
R4
R3
R1
D
Topics
Routing – An Overview Forwarding Table
Mobile Networks Some Semantics Reactive vs Proactive
AODV Routing Routing Table RREQ and RREP
Location-Aided Routing
Routing – Forwarding Table
A Simplified Version of a Forwarding Table Each entry has the following fields:
Destination IP Address Destination Sequence Number Next Hop
Destination IP Address
Destination Sequence #
Next Hop
209.85.148.105 123456 150.250.190.1150.250.1.1 178965 150.250.190.1
209.191.122.70 224870 150.250.190.1
Destination IP Address
Destination Sequence #
Next Hop
209.85.148.105 123456 150.250.190.1150.250.1.1 178965 150.250.190.1
209.191.122.70 224870 150.250.190.1
Destination IP Address
Destination Sequence #
Next Hop
209.85.148.105 123456 150.250.190.1150.250.1.1 178965 150.250.190.1
209.191.122.70 224870 150.250.190.1
Destination IP Address
Destination Sequence #
Next Hop
209.85.148.105 123456 150.250.190.1150.250.1.1 178965 150.250.190.1
209.191.122.70 224870 150.250.190.1
R2
S
R4
R3
R1
D
Routing – Forwarding Table
S refers to D by its IP address. D’s IP address = 150.250.1.1
The following entry tells S who to send the next packet to.
Destination IP Address
Destination Sequence #
Next Hop
209.85.148.105 123456 150.250.190.1150.250.1.1 178965 150.250.190.1
209.191.122.70 224870 150.250.190.1
Destination IP Address
Destination Sequence #
Next Hop
209.85.148.105 123456 150.250.190.1150.250.1.1 178965 150.250.190.1
209.191.122.70 224870 150.250.190.1
Routing – Forwarding Table
Here’s Another Problem: How does the information get in the
forwarding table to begin with?
The Solution Routing protocols will find routes from a source
to a destination. These protocols will fill in the information in
the forwarding table.
Topics
Routing – An Overview Forwarding Table
Mobile Networks Some Semantics Reactive vs Proactive
AODV Routing Routing Table RREQ and RREP
Location-Aided Routing
Mobile Networks
The mobile networks we will be teaching today are known as MANETs
Mobile Ad-hoc NETworks Mobile – the nodes of the network can move Ad-hoc – does not rely on existing infrastructure Network – a collection of computers (nodes) connected
by communication channels Example: disaster relief – the infrastructure was
wiped out but the need for communication exists Since devices are mobile and can move freely,
each device must be able to find new routes itself.
Topics
Routing – An Overview Forwarding Table
Mobile Networks Some Semantics Reactive vs Proactive
AODV Routing Routing Table RREQ and RREP
Location-Aided Routing
Mobile Networks – Some Semantics Node
A computer which must route all messages wirelessly through other nodes
Nodes can move around You can think of nodes as laptops or cell phones that
can not use a radio tower to get a signal Neighboring Nodes
Any two nodes which can directly communicate with each other
Unicast, Multicast, Broadcast Visualizations of each of these are on the following
slides. Flooding
A large number of packets flow through the network that can cause congestion
Packet
For Node
X
Mobile Networks – Some Semantics Unicast
Delivers a message to a single specified node. Here is an example of sending a unicast
message:
Packet
For Node
X
Packet
For Node
X
Packet
For Node
X
Packet
For Node
X
Packet
For Node
X
Packet
For Node
X
Packet For
Nodes X,Y,Z,
T
Mobile Networks – Some Semantics Multicast
Delivers a message to a group of nodes that expressed interest in receiving the message.
Here is an example of flooding a multicast message:
Packet For
Nodes X,Y,Z,
T
Packet For
Nodes X,Y,Z,
T
Packet For
Nodes X,Y,Z,
T
Packet For
Nodes X,Y,Z,
T
Packet For
Nodes X,Y,Z,
T
Packet For
Nodes X,Y,Z,
T
Packet For
Nodes X,Y,Z,
T
Packet For
Nodes X,Y,Z,
T Packet For
Nodes X,Y,Z,
T
Packet For
Nodes X,Y,Z,
T
Packet For
Nodes X,Y,Z,
T
Packet
For All Nodes
Mobile Networks – Some Semantics Broadcast
Delivers a message to all of the nodes in the network.
Here is an example of flooding a broadcast message:
Packet
For All Nodes
Packet
For All Nodes
Packet
For All Nodes
Packet
For All Nodes
Packet
For All Nodes
Packet
For All Nodes
Packet
For All Nodes
Packet
For All Nodes
Packet
For All Nodes
Packet
For All Nodes
Packet
For All Nodes
Topics
Routing – An Overview Forwarding Table
Mobile Networks Some Semantics Reactive vs Proactive
AODV Routing Routing Table RREQ and RREP
Location-Aided Routing
Mobile Networks:Reactive Vs Proactive
Routing protocols are needed to find routes between a source node and a destination node
Reactive – “I need to send information to another node but I don’t have a route yet! I will find one.”
Proactive – “I just entered a network. Before I even begin to send information, I’m going to find a route to every other node in the network just to be prepared ahead of time.”
Mobile Networks:Reactive Vs Proactive
Reactive Only calculate new routes
when they are needed Do not maintain routes to
every node in the network Also known as On
Demand Routing Efficient for low mobility,
light traffic networks. Examples
DSR AODV
Proactive Try to calculate all of the
routes beforehand Actively maintain updated
routes to every node in the network
Also known as Table Driven Routing
Incurs overhead when the network changes
Examples: IS-IS OSPF
Topics
Routing – An Overview Forwarding Table
Mobile Networks Some Semantics Reactive vs Proactive
AODV Routing Routing Table RREQ and RREP
Location-Aided Routing
AODV Routing
d – Hoc Does not rely on pre-existing infrastructure
n – Demand A reactive protocol – only create routes on
demand
istance
ector
A
O
D
V
Vector Distance Vectors are used to calculate routes from
one mobile node to the next since routers are not usedin an ad-hoc protocol
AODV Routing
Designed for mobile networks holding hundreds of nodes where all nodes trust each other.
Used to find a route from a source node to a destination node when no current path is known.
Does this problem sound familiar?
AODV Routing
The Problem From Before: How does the information describing the route
from source node to destination get into the forwarding table to begin with?
The Solution From Before: Routing protocols will find routes from a source
to a destination and will fill in the information in the forwarding table.
This is the job of AODV!
AODV Routing
The basic idea when source S has a route to destination D The forwarding table at S declares to who send
the packets to in order to eventually reach D. A unicast message is sent from S to that
intermediate node. Lots of uninterested nodes will receive the
message but only the particular intermediate node it was designated for will continue to send the packets along to other nodes in the same manner until the packets reach D
AODV Routing
The basic idea when source S does not have a route to destination D S sends out a multicast control packet called
RREQ, or “route request” to all neighboring nodes. Each neighbor checks to see if it is actually the
destination or if it has a route to the destination. If not, send out another RREQ to their own neighbors. This
is called flooding. If any node receives an RREQ and is the
destination or has a route to it, send back a unicast RREP, or “route reply” control packet to the node that sent the RREQ.
AODV Routing
Route Discovery Process via flooding .
RREQ for
Node D
RREQ for
Node D
RREQ for
Node D
RREQ for
Node D
RREQ for
Node D
RREQ for
Node D
RREQ for
Node D
RREQ for
Node D
RREQ for
Node D
RREQ for
Node D
RREQ for
Node D
RREQ for
Node D
RREP for
Node S
RREP for
Node S
RREP for
Node S
AODV Routing
The New Route
Topics
Routing – An Overview Forwarding Table
Mobile Networks Some Semantics Reactive vs Proactive
AODV Routing Routing Table RREQ and RREP
Location-Aided Routing
Routing Table
A Simplified Version of a RoutingTable Each entry has the following fields:
Destination IP Address Destination Sequence Number Network Interface Next Hop Hop Count Lifetime
Destination IP Address
Destination Sequence #
Network Interface
Next Hop Hop Count Lifetime
209.85.148.105 123456 eth0 150.250.1.1 14 126150.250.190.204 178965 eth0 150.250.190.1 3 2544209.191.122.70 224870 wlan0 150.250.1.1 12 1021
Destination IP Address
Destination Sequence #
Network Interface
Next Hop Hop Count Lifetime
209.85.148.105 123456 eth0 150.250.1.1 14 126150.250.190.204 178965 eth0 150.250.190.1 3 2544209.191.122.70 224870 wlan0 150.250.1.1 12 1021
Destination IP Address
Destination Sequence #
Network Interface
Next Hop Hop Count Lifetime
209.85.148.105 123456 eth0 150.250.1.1 14 126150.250.190.204 178965 eth0 150.250.190.1 3 2544209.191.122.70 224870 wlan0 150.250.1.1 12 1021
Destination IP Address
Destination Sequence #
Network Interface
Next Hop Hop Count Lifetime
209.85.148.105 123456 eth0 150.250.1.1 14 126150.250.190.204 178965 eth0 150.250.190.1 3 2544209.191.122.70 224870 wlan0 150.250.1.1 12 1021
Destination IP Address
Destination Sequence #
Network Interface
Next Hop Hop Count Lifetime
209.85.148.105 123456 eth0 150.250.1.1 14 126150.250.190.204 178965 eth0 150.250.190.1 3 2544209.191.122.70 224870 wlan0 150.250.1.1 12 1021
Destination IP Address
Destination Sequence #
Network Interface
Next Hop Hop Count Lifetime
209.85.148.105 123456 eth0 150.250.1.1 14 126150.250.190.204 178965 eth0 150.250.190.1 3 2544209.191.122.70 224870 wlan0 150.250.1.1 12 1021
Destination IP Address
Destination Sequence #
Network Interface
Next Hop Hop Count Lifetime
209.85.148.105 123456 eth0 150.250.1.1 14 126150.250.190.204 178965 eth0 150.250.190.1 3 2544209.191.122.70 224870 wlan0 150.250.1.1 12 1021
Topics
Routing – An Overview Forwarding Table
Mobile Networks Some Semantics Reactive vs Proactive
AODV Routing Routing Table RREQ and RREP
Location-Aided Routing
RREQ – Route Request
An RREQ is made up of the following fields:
RREQ – Route Request
Hop Count ID Number Destination IP Address
Destination Sequence #
Originator IP Address
Originator Sequence #
1 12345 209.191.122.70 55 150.250.190.204 126
Each node asks, “Do I have a path to destination?” “No.” Increment hop count and re-
broadcast.Hop Count ID Number Destination IP
AddressDestination Sequence #
Originator IP Address
Originator Sequence #
1 12345 209.191.122.70 55 150.250.190.204 126
Hop Count ID Number Destination IP Address
Destination Sequence #
Originator IP Address
Originator Sequence #
2 12345 209.191.122.70 55 150.250.190.204 126
Any nodes that have seen this RREQ before ignore it.
Hop Count ID Number Destination IP Address
Destination Sequence #
Originator IP Address
Originator Sequence #
3 12345 209.191.122.70 55 150.250.190.204 126
“Oh, wait, I am the destination!”
RREQ – Route Request
Each node can use the IP Datagram that was wrapped around the RREQ packet. Each node can pull the IP address of the last
node that sent the RREQ. Each node now knows that in order to send a
reply back to Source S, the next hop must be that guy and it knows the hop count too from the RREQ packet.
D now knows who to send to in order to reach S.
D now sends a unicast RREP back to that guy, with intentions of reaching S to let S know everything’s OK
RREP – Route Reply
An RREP is made up of the following fields:
RREQ – Route Request
The Destination now sends a reply back to the source.
The Source has successfully received the RREP packet. Information from the packet can be used in the source’s routing table, such as ‘3 hops to reach D’ and the ‘next hop to reach D’ which it can pull from
the IP Datagram of the RREP it just received.
Topics
Routing – An Overview Forwarding Table
Mobile Networks Some Semantics Reactive vs Proactive
AODV Routing Routing Table RREQ and RREP
Location-Aided Routing
Location Aided Routing (LAR) AODV creates unnecessary overhead
when RREQ packets flood the entire network.
LAR aims to reduce this overhead by only allowing packets to propagate towards the destination.
LAR can use Global Positioning System (GPS) to determine the direction to send packets.
Location Aided Routing (LAR) Knowledge of each node’s physical location at
some previous point in time will help send packets in the right direction.
LAR does NOT use directional antennae. Instead, upon receiving an RREQ with
additional positional information, each node will determine if it is “in the right direction” of the destination.
If so, the node will re-broadcast the packet. If not, the node will ignore it, saving on
overhead.
Location Aided Routing (LAR) LAR Scheme 1
Knowing the average velocity (v) at which the destination is moving, we can draw a circle around the last known destination’s coordinates with radius v.
The destination is likely to bein this circle.
We will box this circle as sown: Only nodes inside this box
will continue to broadcastthe packet.
Location Aided Routing (LAR)
Location Aided Routing (LAR) LAR Scheme 2
LAR Scheme 2 does not rely on velocities of nodes.
The source can send out the destination’s last known coordinates in the RREQ packet along with its own.
Any node that receives the RREQand is closer to the destinationthen the last sender of the RREQshould re-broadcast the RREQwith its own coordinates attached.
Location Aided Routing (LAR)
Geo AODV
Our research was to improve on an idea for a better LAR algorithm.
A better algorithm will cause less overhead in an AODV network.
Former Rowan students, working with Dr. VH, developed an algorithm, Geo AODV.
We analyzed the algorithm and put it to the test against other LAR algorithms.
Geo AODV
Geo AODV defines an initial “flooding angle” from the source aimed towards the destination.
The cone-shaped figure might make for a more accurate bounds to the actual path from S to D then a rectangle.
Any node inside the conewill rebroadcast the RREQ.
Any node outside willignore it.
Implementation
We used OPNET 16.0 to implement the different routing protocols in order to observe the results.
Testing
The whole point of Location Aided Routing is to reduce the number of messages being broadcast. This cuts down on overhead This allows the network to process more
requests in a shorter period of time
We tested 2 schemes against regular AODV and looked at the number of RREQs being generated
Results
References
http://ntrg.cs.tcd.ie/undergrad/4ba2.05/group11/index.html
http://wiki.uni.lu/secan-lab/Reactive+Routing.html http://wiki.uni.lu/secan-lab/Proactive+Routing.html