Valuable Detours: Least-Cost any path Routing
ABSTRACT:
In many networks, it is less costly to transmit a packet to any
node in a set of neighbors than to one specific neighbor. This observation was
previously exploited by opportunistic routing protocols, by using single-path
routing metrics to assign to each node a group of candidate relays for a particular
destination.
This project addresses the least-cost any path routing (LCAR) problem: how
to assign a set of candidate relays at each node for a given destination such that the
expected cost of forwarding a packet to the destination is minimized. The key is
the following tradeoff: on one hand, increasing the number of candidate relays
decreases the forwarding cost, but on the other, it increases the likelihood of
“veering” away from the shortest-path route. Prior proposals based on single-path
routing metrics or geographic coordinates do not explicitly consider this tradeoff,
and as a result do not always make optimal choices.
The LCAR algorithm and its framework are general and can be applied
to a variety of networks and cost models. We show how LCAR can incorporate
different aspects of underlying coordination protocols, for example a link-layer
protocol that randomly selects which receiving node will forward a packet, or the
possibility that multiple nodes mistakenly forward a packet. In either case, the
LCAR algorithm finds the optimal choice of candidate relays that takes into
account these properties of the link layer.
Finally,
we
apply
LCAR
to
low-power,
low-rate
wireless
communication and introduce a new wireless link-layer technique to decrease
energy transmission costs in conjunction with any path routing. Simulations show
significant reductions in transmission cost to opportunistic routing using singlepath metrics. Furthermore LCAR routes are more robust and stable than those
based on single-path distances, due to the integrative nature of the LCAR’s route
cost metric.
ARCHITECTURE:
EXISTING SYSTEM:
Link-layer any casting has been previously proposed and motivated in
various forms. These works focus on mechanisms to implement any cast
forwarding at the link layer, and assume that the network layer maintains a list of
possible relay candidates that is provided to the link layer. These works do not
propose specific Strategies for the selection of these candidates by the routing
protocol, and the LCAR algorithm could be used to feed these link layers with
relay candidates. Jain and Das go a step further by integrating any cast extension of
the link layer with the multi-path AODV routing protocol. They observe the same
tradeoff as between number of candidates and path length. Motivated by an
empirical evaluation, they modify AOMDV to allow the use of paths up to one hop
longer than the shortest path.
Disadvantage
 The single-path metric effectively disqualifies nodes.
PROPOSED SYSTEM:
This project addresses the least-cost any path routing (LCAR) problem:
how to assign a set of candidate relays at each node for a given destination such
that the expected cost of forwarding a packet to the destination is minimized. The
key is the following tradeoff: on one hand, increasing the number of candidate
relays decreases the forwarding cost, but on the other, it increases the likelihood of
“veering” away from the shortest-path route. Prior proposals based on single-path
routing metrics or geographic coordinates do not explicitly consider this tradeoff,
and as a result do not always make optimal choices. The LCAR algorithm and its
framework are general and can be applied to a variety of networks and cost
models.
We show how LCAR can incorporate different aspects of underlying
coordination protocols, for example a link-layer protocol that randomly selects
which receiving node will forward a packet, or the possibility that multiple nodes
mistakenly forward a packet. In either case, the LCAR algorithm finds the optimal
choice of candidate relays that takes into account these properties of the link layer.
Advantage:
 Increases the likelihood of veering away from the shortest-path route.
 Wireless communication and introduce a new wireless link-layer technique
To decrease energy transmission costs in conjunction with any path
routing.
MODULES:
Any cast link cost
We must first generalize the notion of link cost to account for any cast
rather than unicast forwarding. We define the any cast link cost (ALC) as the cost
to send a packet from any node in the. Similarly to standard unicast link costs,
choosing any cast link cost is a modeling decision that depends on the cost
criterion of our network. Note that for any path routing to be worthwhile, it must
be used with any cast link costs that decrease when the candidate set is enlarged;
otherwise there is no advantage to having more than one candidate relay, and any
path routing will end up computing least-cost single-path routes. Any ALC must
have two simple properties. This protocol must ensure that the nodes receiving a
packet all agree and select the correct relay in a distributed way. While an ideal
protocol does this with complete reliability, it is in practice possible that the
outcome of executing the coordination protocol is incorrect. One such error would
be that more than one receiver forwards a packet.
.
Transmission-count:
We can generalize the expected transmission count metric for unicast
transmission. This metric counts the expected number of transmissions to
successfully deliver a packet across an unreliable unicast link. With link-layer any
cast, the expected number of transmissions until any node in J receives the packet.
Its expression is Of course, the above definition assumes spatial independence,
such that transmission is received independently by nodes. Our aim here is not to
derive a complex metric that captures spatial loss correlations in general
conditions; but we note that the LCAR framework can accommodate such metrics
and others.
System Requirements:
Hardware Requirements:
 System
: Pentium IV 2.4 GHz.
 Hard Disk
: 40 GB.
 Floppy Drive
: 1.44 Mb.
 Monitor
: 15 VGA Colour.
 Mouse
: Logitech.
 Ram
: 512 Mb.
Software Requirements:
 Operating system
: Windows XP.
 Coding Language
: ASP.Net with C#
 Data Base
: SQL Server 2005
SYSTEM DESIGN
Data Flow Diagram / Use Case Diagram / Flow Diagram
The DFD is also called as bubble chart. It is a simple graphical
formalism that can be used to represent a system in terms of the input data to the
system, various processing carried out on these data, and the output data is
generated by the system.
Dataflow Diagram:
SERVER
ROUTER
CLIENT
Browse a
received path
IP Address
Browse a
File
Connecting..
IP Address
Connecting..
Flle Receive
Selec Path
FIle Transfer
Send File
Error message
Re Send File
File Received
End
Class Diagram:
Activity Diagram:
CLIENT
SERVER
Browse
IP Address
IP Address
Select a
Receiving Path
Browse a
File
Select Path
ROUTER
Send
Connecting..
NO
coneection
Error Message
FILE RECEIVE
Yes
Connecting..
Error Message
FILE TRANSFER
TRANSACTION
FAILED
ReSend
FILE RECEIVE
Sequence Diagram:
ROUTER
SERVER
CLIENT
Start File Transfer
Bytes Transferred
Bytes Received
Send files
File Transferred Success
Acknowledgement
File Received
Use Case Diagram:
Receiving
Path
IP Address
Select path
CLIENT
SERVER
Send
ROUTER
Error Message
Browse a File
Receive a File
Resend