An Advanced Hybrid Peer to Peer Network

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AN ADVANCED HYBRID PEER TO PEER BOTNET

GroupMembers

CH.V.V. CHAKRAVARTHY 09UJ1A1223A.MAHENDER 09UJ1A1220

P.KRISHNA GOPAL 09UJ1A1230

K.MAHESH KUMAR 09UJ1A1226

Internal Head

Miss. J. VASAVI


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INTRODUCTION

In the past few years, we have seen a rapid expansion in

the field of mobile computing due to the proliferation of

inexpensive, widely available wireless devices.

Digital radio technology has tremendous impact on

todays mobile computing.


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Wireless Networks

Infrastructure- based Networks:

Traditional cellular Systems(base station infrastructure)

Wireless LANs:

Infrared or radio links.very flexible within the reception area.

Low bandwidth compared to wired networks.

Ad hoc networks:Useful when infrastructure not available.

Military applications, rescue, home networking.


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DEFINITION

A mobile ad hoc network is an autonomous collection of

mobile devices (laptops, smart phones &sensors) thatcommunicate with each other over the wireless links.
http://images.yourdictionary.com/images/computer/WMESH1.GIF


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Setting up of fixed access points and backbone

infrastructure is not always viable

Infrastructure may not be present in a disaster area or

war zone

Infrastructure may not be practical for short-range

radios; Bluetooth (range ~ 10m)

Ad hoc networks:

Do not need backbone infrastructure support

Are easy to deploy Useful when infrastructure is absent, destroyed or

impractical

Why Ad Hoc Networks ?


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EXISTING SYSTEM

the throughput for each node degrades as the

number of nodes increases under the competition-driven view of network.

These network can be characterized as one-to-one

and one-many communications.

PROPOSED SYSTEM

Many to Many Communication.

By using this approach MPTs and MPRs occur

simultaneously.

Receiver complexity of all nodes increases.


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Ad hoc wireless networks

No infrastructural support.

Nodes act as a routers. Mobility of nodes.

Single and Multi hop communication.


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CHARACTERISTICS

Nodes are act as both Host and Routers.

No centralized server and infrastructure.

Dynamic network topology, frequent routingupdates.

Limited Security


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MANETs has the capability of establishingnetworks quicker and faster.

Electromagnetic waves are used to access the

information.

Remotely connected to the network

from your laptop.

It can be used any where, any time.


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Nodes responsible for forwarding packets form one

node to another node.

MANET node has ability of computing, switching and

communicating independently.

Wireless transmission links consume very less power.

Disadvantages

Higher error rates.

Lower bandwidth

More Frequent Disconnections.


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Media Access

Routing

Multicasting

Energy Efficiency

TCP Performance

Security and privacy


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Hidden terminals A sends to B, C cannot receive A C wants to send to B, C senses a free medium (CS fails) collision at B, A cannot receive the collision (CD fails) A is hidden for C

Exposed terminals B sends to A, C wants to send to another terminal (not A or

B) C senses carrier, finds medium in use and has to wait A is outside the radio range of C, therefore waiting is not

necessary C is exposed to B

BA C

Medium Access Control in MANET


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Multiple Access with Collision Avoidance (MACA)

MACA uses signaling packets for collisionavoidance

RTS (request to send)

sender request the right to send from a receiver with ashort RTS packet before it sends a data packet

CTS (clear to send)

receiver grants the right to send as soon as it is ready to

receive


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MACA Solutions

MACA avoids the problem of hidden terminals

A and C want to

send to B

A sends RTS first

C waits after receiving

CTS from B

MACA avoids the problem of exposed terminals

B wants to send to A, Cto another terminal

now C does not have

to wait, as it cannot

receive CTS from A

A B C

RTS

CTSCTS

A B C

RTS

CTS

RTS


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Transmission Control Protocol (TCP)

Reliable ordered delivery Reliability achieved by means ofretransmissions if necessary

End-to-end semantics Receiver sends cumulative acknowledgements for in-sequence packets

Receiver sends duplicate acknowledgements for out-of-sequence packets

Implements congestion avoidance and control using sliding-window Window size is minimum of

receivers advertised window - determined by available buffer space atthe receiver

congestion window - determined by the sender, based on feedback fromthe network

Congestion window size bounds the amount of data that can be sent perround-trip time

Transport in MANET


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Several factors affect TCP performance in MANET

Wireless transmission errorsmay cause fast retransmit, which results inretransmission of lost packet

reduction in congestion window

reducing congestion window in response to errors is

unnecessary

Multi-hop routes on shared wireless medium

Longer connections are at a disadvantage compared to shorter

connections, because they have to contend for wireless accessat each hop

Route failures due to mobility


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User Datagram Protocol (UDP)

Studies comparing different routing protocols for MANET typically

measure UDP performance

Several performance metrics are used

routing overhead per data packet

packet delivery delay

throughput/loss Many variables affect performance

Traffic characteristics

Mobility characteristics

Node capabilities

Difficult to identify a single scheme that will perform well in allenvironments

Several relevant studies [Broch98Mobicom, Das9ic3n,Johansson99Mobicom, Das00Infocom, Jacquet00Inria]


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Mobile TCP

Improve overall Throughput and lower

delay rate.

It Maintains TCP end-end semantics.

Provide more efficient handover.


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Routing in MANET


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Destination-Sequenced Distance-Vector (DSDV)

Each node maintains a routing table which stores

next hop, cost metric towards each destination a sequence number that is created by the destination itself

Each node periodically forwards routing table to neighbors

Each node increments and appends its sequence number when sendingits local routing table

Each route is tagged with a sequence number; routes with greatersequence numbers are preferred

Each node advertises a monotonically increasing even sequencenumber for itself

When a node decides that a route is broken, it increments thesequence number of the route and advertises it with infinite metric

Destination advertises new sequence number


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(A, 1)

(B, 0)

(C, 1)

(A, 1)

(B, 0)

(C, 1)

Distance Vector Updates

C

Dest. Next Metric A A 1

B B 0

C C 1

Dest. Next Metric A A 0

B B 1

C B 3 2

1 1

Dest. Next Metric A B 3 2

B B 1

C C 0

BA

B broadcasts the

new routing

information to his

neighbors

Routing tableis updated


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An Advanced Hybrid Peer to Peer Network