Caching Strategies based on Information Density Estimation

In Wireless Ad hoc Networks

By

Haritha Ghantasala

MCA III Year

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What is an Ad hoc NetworkCollection of mobile wireless nodes forming

a network without the aid of any infrastructure or centralized administration

Nodes have limited transmission rangeNodes act as a routers

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Ad Hoc Networks

Rapidly deployable infrastructure◦ Wireless: cabling impractical◦ Ad-Hoc: no advance planning

Backbone network: wireless IP routers

• Network of access devices• Wireless: untethered• Ad-hoc: random deployment

• Edge network: Sensor networks, Personal Area Networks (PANs), etc.

• Disaster recovery• Battlefield• ‘Smart’ office

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Ad Hoc Network

Characteristics◦ Dynamic topologies◦ Limited channel bandwidth◦ Variable capacity links◦ Energy-constrained operation◦ Limited physical security

Applications◦ Military battlefield networks◦ Personal Area Networks (PAN)◦ Disaster and rescue operation ◦ Peer to peer networks

What is Cache In computer science, a cache is a

component that transparently stores data so that future requests for that data can be served faster.

If requested data is contained in the cache it is cache hit

If it is not in the cache it is Cache Miss

Difference between buffer and cache A buffer is a temporary memory location that is

traditionally used because CPU instructions cannot directly address data stored in peripheral devices. Thus, addressable memory is used as an intermediate stage.

The buffered data are written to the buffer once and read from the buffer once.

A cache also increases transfer performance. A part of the increase similarly comes from the possibility that multiple small transfers will combine into one large block.

The same datum will be read from cache multiple times, or that written data will soon be read.

AbstractIn a Wireless Ad Hoc Network nodes exchange

information in peer-to-peer fashion.

Proper use of large-sized and small-sized caches.

Creation of content diversity within the neighborhood.

Simulating caching algorithms to achieve a resource efficient information access.

ObjectiveOur main objective of this project is to

propose a novel asymmetric cooperative cache approach, where the data requests are transmitted to the cache layer on every node, but the data replies are only transmitted to the cache layer at the intermediate nodes that need to cache the data. This solution not only reduces the overhead of copying data between the user space and the kernel space, it also allows data pipelines to reduce the end-to-end delay.

Modules

1. Network Joining Module(Cache Implementation)

2. Authentication Modules3. Operations Modules

a) Sendb) Receivec) View Neighborsd) Transactionse) Log

1. Network Joining Module (Cache Implementation)

This module is used to join in to the network

with proper handshake credentials such as ip

address and port numbers which are provided

to the system for both client and server in the

form of configuration files. Using these first

the server is deployed. And then each client

connects to the server using his own

customized configuration files.

2. Authentication Module:

By using this module each node joins

network completely by getting validated

by a monitoring node/server. Thus after

this successful operation a node

completely joins the network. Ciphering

schemes are implemented here which

acts as replacements for certificate based

methods.

3. Operations Modules:

By using this module nodes will get access to all the services provided

by the network. This module is having following sub functionalities.

Send: By using this functionality nodes can send data in the network. 

Receive: By using this functionality nodes can receive data from the

network. 

View neighbors: By using this functionality nodes can see all the

existing neighbor nodes in the network.

Transaction: A detailed information accumulated of performed

transactions(joining, sending, receiving) in the network.

Log: A log view maintained and displayed for all the transactions in the

network at each client

Cache

Java Network

Node Admission processNode

Network

Information

Node Communication

<<include>>

Network Operation Use case:

Project Use case

stone in NODE cache using hamlet strategy

<<extends>>

Determine cache DROPTIME

NODE Determine content replacement in cache

Recive Information

NETWORK

Informanation presence in neighbours

Class & Package diagram

Network

Server

ClientId[]

Operations()Trackclients()Server()

Node Cache Simulation

A A

A

Operations

MsgNoOfCilent

Node

id

join()send()receive()communication()validateothers()

Query

query

startquery()duplicate()solved()relay()

Information

informationquery

searchquery()recieveInfo()duplicate()solved()chunk()stone()discard()

NODE

ipneigbours[]cache

updatecache()createcache()relay()providechunk()

SEQUENCE DIAGRAM

:Network:Node :Cache :Query :Information :Neigbhours

join()

joined

updateCache()

cacheUpdated()

requestInformation()

contact()

neigbhours list()

sendQuery()

check each cache

Results

Results

requestQuery()

Search()

get()

process()

Information

informanation

share()

acknowledgment

Information

COLLABRATION DIAGRAM

:Node

:Cache

:Query

:Information

:Neigbhours

:Network

10: check each cache

15: process()

1: join()

2: joined

4: updateCache()

5: cacheUpdated()

6: requestInformation()14: Search()

12: Results18: Information

7: contact()8: neigbhours list()

9: sendQuery()11: Results

16: get()

17: Information

3: informanation

13: requestQuery()20: acknowledgment

19: share()

ACTIVITY DIAGRAM

ACTIVITY DIAGRAM 2

COMPONENT DIAGRAM

DEPLOYMENT DIAGRAM

NODE.jar<<system>>

Assumptions Assume a content distribution system

where the following assumptions hold:• A number I of information items is available to

the users, with each item divided into a number C of chunks

• User nodes can overhear queries for content and relative responses within their radio proximity by exploiting the broadcast nature of the wireless medium

• User nodes can estimate their distance in hops from the query source and the responding node due to a hop-count field in the messages.

Flowcharts of the processing of (a) query and (b) information messages

Hamlet Framework Information Presence Estimation

A node n within its reach range computes:

• Provider counter dic(n, j)

dic(n, j) = dic(n, j) +1 ∕hQ

• Transit counter ric(n, j)

ric(n, j) = ric(n, j) +1 ∕hP+1 ∕hQ

Provider Node and Transit Node

Hamlet Framework

Information Presence Estimation• In case of not related information

message

ric(n, j) = ric(n, j) +1 ∕hP

• Presence Index of chunk c of

information i given as

pic(n, j) = min {1, dic(n, j) + ric(n, j)}

Existing SystemThe novel applications such as mobile

multimedia are likely to overload the wireless network (as recently happened to AT&T following the introduction of the iPhone).

It is conceivable that a peer-to-peer system could come in handy, if used in conjunction with cellular networks, to promote content sharing using ad hoc networking among mobile users.

Disadvantages of Existing SystemIn the caching strategies based on

informationdensity estimation in Mobile Ad Hoc

Networks(MANET), which faces some

disadvantages.

Wasteful in terms of the networks total bandwidth

Message DuplicationSelective Flooding

Proposed SystemIn the proposed system, we address the

issue ofdisadvantages faced in flooding routing

protocol,using DSR and AODV protocol. The

advantages ofour proposed system are:It eliminates table-driven approach.We simulate and show the node routing

between the cells, with all the information such as number of cells, number of hops, time taken etc.

System Requirements:

Hardware Requirements: PROCESSOR : PENTIUM IV 2.6 GHz RAM : 512 MB DD RAM MONITOR : 15” COLOR HARD DISK : 20 GB KEYBOARD : STANDARD 102 KEYS MOUSE : 3 BUTTONS

Software Requirements: Front End : Java( Swings

)Tools Used : Net beans

7.0Operating System : Windows

XP

Server Started with port number 5555:

CLIENT1 DETAILS

CLIENT1 JOINED TO THE NETWORK

CLIENT1’s NETWORK DETAILS

CLIENT2 DETAILS

CLIENT2 JOINED TO THE NETWORK

CLIENT2’s NETWORK DETAILS

CLIENT1 IS DISPLAYING UPDATED NEIGHBOR NODES

CLIENT1 DISPLAYING UPDATED NETWORK DETAILS

CLIENT3 DETAILS

CLIENT3 JOINED TO THE NETWORK

CLIENT1 DISPLAYING UPDATED NEIGHBOR NODES

CLIENT2 DISPLAYING UPDATED NEIGHBOR NODES

CLIENT3’s NETWORK DETAILS

CLIENT1 UPDATED ITS NETWORK DETAILS

CLIENT2 UPDATED ITS NETWORK DETAILS

CLIENT1 WANTS TO SEND A MESSAGE TO CLIENT3

MESSAGE TRANSFERRED INFORMATION IS DISPLAYED IN CLIENT1’S TRANSACTIONS COLUMN

MESSAGE RECEIVED INFORMATION IS DISPLAYED IN CLIENT3’S TRANSACTIONS COLUMN

MESSAGE LOG IS CREATED WITH TIME STAMP DISPLAYING THE INFORMATION LIKE SOURCE ADDRESS, DESTINATION ADDRESS AND ALSO THE MESSAGE

Scope of the project

However, the solution that was proposed is based on the formation of an overlay network composed of “mediator” nodes, and it is only fitted to static connected networks with stable links among nodes. These assumptions, along with the significant communication overhead needed to elect “mediator” nodes, make this scheme unsuitable for the mobile environments that we address.