Abstract Computer Networks

8/8/2019 Abstract Computer Networks

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Liverpool John Moores University

Computer Networks

Abstract:

The main objective of the paper deals with

the description about internet and difficulties

in internet population.

The internet population measurement

techniques are discussed in brief. Also

provides the nature of address crisis and the

time left before exhaustion i.e, nothing but

IP address exhaustion (IPV4).

The transition strategies of deployment path

of IPV6 are also discussed in detailed. The

transition of IPv4 and IPv6 and the different

deployment methods are discussed in this

research paper.

Networks is defined as a group. Computer

networks is defined as a of computers that

will be having connection among them inorder to communicate with one another.

Internet is a global system that is

interconnected among the computer

networks that use the standard internet

protocol suite (TCP/IP) to serve billions of

users world wide.

Population is nothing but a group of

individual persons present in a particular

location are called as population.

Internet Population:

Definition of Internet Population:

Internet population can be defined as the

population or the total number of people

using the internet. The users of internet

include Internet Service Providers, normal

users, industries, organizations,

manufacturers that can be able to use the

internet through different means of

transmitters and transmission medium.

The term internet can also be defined as the

electronic communications network and

organizational computer facilities around

the world.

The total number of users that are using the

internet world wide can be vary from time to

time. From the past few years the internethas brought vast changes in different fields.

But it is very difficult to estimate the total

number of users that are using internet. In

olden days internet was largely unknown to

most consumers. The first service that

provided online services of internet interface

was the prodigy service. At that time the

consumer was not able to use it in a

satisfactory manner because the band width

is very narrow. The variations of internet

through world wide are various statistics.


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Internet is used for exchanging data or

transmission of data. People can transmit the

data from one place to another by using

internet. This can be possible by the protocol

TCP/IP ( Transmission Control

Protocol/Internet Protocol) that is used.

In todays life internet has become the most

important part.

Based on different countries the usage of

internet population can be estimated as

follows.

According to the survey done on the internet

users in september 2009 the regions divided

based on the usage are shown in detailed.

1.73 billion Internet users worldwide.

18% Increase in Internet users.

738,257,230 Internet users in Asia.

418,029,796 Internet users in Europe.

252,908,000 Internet users in North

America.

179,031,479 Internet users in LatinAmerica / Caribbean.

67,371,700 Internet users in Africa.

57,425,046 Internet users in the Middle

East.

20,970,490 Internet users in Oceania /

Australia.

The statistical view of the above details is

shown below in the form of a pie chart.The

percentage of each region is addressed by

various colours.

Fig:1.Internet Users through out the world

One more statistical view of internet

population based on the top ten languages is

as follows. It indicates the number of people

that use the internet through out the world.

The top various languages discussed in the

below graph are English, Chinese, Spanish,

Japanese, Portuguese, German, Arabic,

French, Russia, Korean.


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Fig:2. Top ten languages in internet in the

year 2010

Internet Population Measurement

Techniques:

It is necessary to know that why do internet

wants the measurement.

In 1994 the Internet was a largely unknown

to consumers. Most consumers had an

experience that it was commercial online

services, Computer Serve, Prodigy, and the

rapidly growing American Online. A

smattering of private bulletin board systemswere available to consumers, and few of

them provided consumer-ready access to the

Internet. Internet addressable email was only

just available on these systems.

The Internet was not well suited to

consumer use at the time owing to the very

narrow bandwidth, and the lack of organized

content. The commercial online services

were far better at working within the

bandwidth limits, and provided a great deal

of organization to the content they offered.

Users of the commercial online services far

outnumbered Internet users in the mid

1990's.

The commercial online services was not indemand at the time of external audience

measurement. The online services are

having excellent subscriber counting

mechanism like subscription accounts to

keep track of their performance. Standard

accounting and internal metrics met most of

their measurement needs. A simple periodic

survey was sufficient to relative market

share and none but the curious were

otherwise interested in the size and

composition of each of the firm's audiences

because no third-party significant decisions

were being made based on the estimates.

Technical advances were providing more

people with easier access to the Internet.

Investment began flowing into Internet

companies, particularly in Silicon Valley.


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The convergence of these factors, significant

growth in the audiences and huge interest

and concern in the Internet from media,

created a great demand for a world class

measurement for Internet.

There are many techniques that had been

used for measuring internet measurement by

using various measurement techniques. But

they are having some problems that have

been arised in this process.

However, it is highly impossible to count the

number of users directly. Also we can count

the number of hosts which are connected to

the Internet. There have been two methods

of counting the connected hosts. They are as

follows

DNS Survey

Reverse Pointer

Apart from this, there are many other

techniques in order to measure the internet

population and they are not efficient.

There are three primary methods of Internet

audience measurement in use today, each

measurement having several variations.

Measurement from a sample of users

who are metered (electronic measurement)

Measurement from a sample of users

who are surveyed (recall measurement)

Measurement from analysis of server

log files or their equivalents

Each of these measurement approaches have

some strengths and weaknesses and can

generally be viewed to work in

complementary ways. Although each

measurement approach is more appropriate

in certain situations than the others. That is

each of the measurement is having some

individual approach compared to the other

approaches.

There are five steps for measuring Internet

audience using a sample of individuals.

The first is to define the universe of

individuals and their circumstances, and to

be very clear on which behaviors are to be

measured. This is a very important step, as it

serves as the foundation on which all

measurement follows. Once a universe is

defined, it must be measured in its own

right.

Next, a representative sample of

universe members must be recruited. The

behavior from this sample will be projected

to the previously described measured

universe.


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The recruited sample must be

interviewed to capture personal and

household level demographic characteristics

for subsequent analysis.

The sample must also be installed

with the electronic measurement system,

typically the meter. Once meters are

installed, a series of edit rules must be

developed and applied to the data that is

returned to the central office. These edit

rules determine which respondents arereliably returning usage data.

The last step is to weight the sample

to correct any demographic biases in the

installed, in-tab sample versus the universe

estimates, and then project the weighted

sample to the universe.

DNS Survey: This method had a great

survey on DNS (Domain Name System)

database, and counts the unique names of

computers appearing on it. Also it gathers

DNS records from remote sites, and looks

into them. The DNS structure is below.

Fig.3.Domain Name System Tree

In Fig. 3, each node stands for a domain.

There are sub-domains under a domain. For

example, jp domain has ac, co, ne, hokkaido,

etc. as sub-domains. The primary function of

DNS is to convert a domain name IP

address. To convert a name to its IP address,

a host name is represented. FQDN is a

single-word hostname followed by full

domain names which is used to convert the

name represented. It can identify a unique

host name anywhere in the world. If the

name is properly given to DNS, you can get

the answer.IP address is found in the server,

it asks other servers to look for the address.

The process is repeated recursively. It

gathersall the DNS databases in the world


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and utilizes a function of DNS, called zone

transfer, which gives all the records in a

DNS server to the requester.

Transferring domain database is originally

intended to be used by other name servers.

These name servers work as the secondary,

or backup server for the name server. Thus,

it is safe to limit the access ofdomain data

fromunauthorized

hosts.

The method we tried first is what RIPE

Coordination Centre uses to count hosts in

Europe. Japan Network Information Center

(JPNIC) also uses it to count hosts in Japan.

The program transfers the zone file from the

name server (DNS) of the top domain, jp.

Then, it looks at the name server record (NS

record), to recursively transfer zone files for

the sub domains. In this way, the whole

DNS tree can be traversed. Although this

method is very simple and efficient and also

efficient, there is a limitation. Some of the

name servers refuse to transfer zone files.It

is for security and safety measures.These

servers allow zone transfer only to trusted

networks or hosts, such assecondary servers

which work as backup for that particular

domain.

Disadvantages:

This technique seems to be very simple and

easy to calculate but the major disadvantage

in this is, Recently, some sites refused to

allow DNS records to be transferred. They

refused the transfer, because of some illegal

intruders. Since this security issue is serious,

the zone transfer would be refused by many

sites. Because of security context this

method is sometimes not much affordable.

Because sometimes hackers may hack the

Domain Name Server records to gather the

information for their advantage.

Reverse pointer:

Reverse pointer is another internet

measurement technique.The reverse pointer

is a Domain Name System record stored in

the database which will give a map from an

IP address to host name. It starts counting

hosts with the IP address. There is a DNS

record in the database which gives a

mapping from an IP address to a host name.

The record is called a reverse pointer. This

method sometimes also can be called as

Reverse mapping because of the fact that it

is following an opposite direction ofconversion method which is quite opposite

to the functionality of Domain Name

System. If an IP address is successfully

translated to a name, it is counted as a host.


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Advantage: They dont have to transfer zone

information. When converting an IP address

into hostname this method does not transfer

zone information. That is a safety

measurement for this method.

Disadvantages:

If an IP address is assigned to a user

independently irrespective of their

geographical location, network topology we

cannot be able to determine which addresses

are used in different regions and region

names. If this is the case we need to consult

the IP address database in that specific and

particular region to recognize the range of IP

addresses to be count. A host does not

always have reverse translation back to their

domain especially when a translated name is

outside of the domain we are counting, it

affects the result.

Primitive Method: A primitive method is to

count hosts by sending ICMP ECHO to

every possible hosts.This method counts the

hostnames by sending an ICMP ECHO

command to every possible destination.

ICMP ECHO is a packet which is sent to alldestinations. The command used is ping

command.Target hosts can be a subset of the

target domain. More practical method that

is to count hosts by transferring zone data of

the past 30 days", especially if the most

recent visit occurred within the past 45 days.

At the same time, these large-scale surveys

are very valuable devices for understanding

the composition of audiences at certain

kinds of sites. Good targeting objectives can

be set up (e.g., high-income professionals

contemplating purchasing a new luxury car

in the next 12 months). These surveys are

often the best solutions for inter-media

comparisons as well, helping plannersunderstand how various Internet media

properties fill in a campaign built from

traditional media.

Measurement Methodology:

Measurement or the analysis of peer

behaviour in P2P sharing systems, we set

up a client node. Gnutella protocol is

publicly available, there are a number of

client implementations. To perform the

measurements in the Gnutella network, we

modify the open-source of it. Gnutella client

Mutella [Mut04], to record a trace of all

Gnutella messages routed through the node.

Inter

net Protocol Versio

n4:

IPv4 is the most widely used version of the

Internet Protocol. It defines IP addresses in a

32-bit format, which looks like

123.123.123.123. Each three-digit section


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for 2,031,616 networks, each with up to 256

hosts), termed the Class Cspace.

The remaining eighth of the space was held

in reserve.

Addressing inIPv4:

However, some are reserved for special

purposes such as private networks or

multicast addresses. This reduces the

number of addresses that can be allocated as

public internet addresses. This limitation has

helped stimulate the push towards IPv6,

which is currently in the early stages of

deployment and is currently the only

contender to replace IPv4.

Fig:4. Web Server during the year 2009

Fig:5. Web Browser during the year 2009

Assessments of crisis of IPv4 in terms of

Time scale:

Some of the recent predictions for the IPv4

exhaustion dates are:

This report is auto-generated by a daily

script.

The graph below is showing the deployment

on the time scale.


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Graph:1

The graph below shows the exhaustion date

of IPv4 on timescale basis by Geoff huston:

Graph:2

The below graph shows the exhaustion date

by Tony hain of Cisco systems.

Graph:3

The current status of the IPv4 space is:

Fig:6. Status of IPv4 Space

Draw Back:

One major drawback with the IPV4 is there

are lots of addresses are being wasted

because of classification of IP address

distribution.


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Use Of Published Eviden

ce An

d Opin

ion

:

There are three stages in address allocation.

The pool of IP addresses is managed by the

Internet Assigned Numbers Authority

(IANA). Blocks of addresses are allocated to

Regional Internet Registries (RIRs), who in

turn allocate smaller blocks to Local Internet

Registries (LIRs) or Internet Service

Providers(ISPs).

Any individual IPv4 address can be in any

one of five states

reserved for special use, or

part of the IANA unallocated address pool,

part of the unassigned pool held by an RIR,

assigned to an end user entity but not

advertised in the routing system, or

assigned and advertised in BGP.The current

totals of IP addresses according to this set of

states is shown below

Graph:4

This status can be further categorized per

RIR, as shown in below

Graph:5

Exhaustion will occur on all continents at

the same time, as all registries follow similar

allocation policies, with for about 12 to 18

months stock allocated at each request. Only

specific organizations that requested


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These dates lie within a depreciation time of

five to ten years of network equipment that

is currently being acquired.

Less than three years until the first RIR

exhaustion is a short time for the entire

industry to transition to IPv6. This situation

is aggravated by the fact that until

exhaustion there will be no significant

demand. David Conrad, the general manager

of IANA acknowledges, "I suspect we are

actually beyond a reasonable time framewhere there won't be some disruption. Now

it's more a question of how much." Geoff

Huston claims we should have started the

transition to IPv6 much earlier, such that by

the exhaustion date it would be completed,

with all devices IPv6-capable, and IPv4

getting phased out.

IPV6 Deployment:

The IPv6 data gram format is shown in the

following figure.The most important

changes introduced in IPv6 are evident in it.

The 32-bit data gram format consists of the

following options.

y Versiony Traffic classy Flow label

y Payload lengthy Next headery Hop limity Source and destination addressesy Data

Fig:7 IPV6 Datagram Format

The IPv6 is the newer version of the internet

protocol. IPv6 is the longer-term outcome

which has been developed to overcome the

difficulties occurred due to IPv4.

IPv6 Addressing:

The address length has been increased

significantly to expand the available address

space. The IPv6 address is 128 bits (or 16

bytes) long, which is four times as long as

its predecessor.


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Because every single bit of added address

length doubles the number of addresses

available, the size of the IPv6 address space

is really huge. It contains 2^128 which is

about 340 billion billion billion billion

different addresses which definitely should

suffice for a very long time. Addresses are

written using 32 hexadecimal digits. The

digits are arranged into 8 groups of four to

improve the readability. There are different

types of IPv6 addresses Unicast, Anycast

and Multicast. Unicast addresses are the

well known addresses. A packet sent to a

unicast address arrives exactly at the

interface belonging to the address. Anycast

addresses are syntactically indistinguishable

from unicast addresses but they address a

group of interfaces. The packet destined for

an anycast address will arrive at the nearest

interface. Anycast addresses may only be

used by routers. Multicast addresses identify

a group of interfaces. A packet destined for

a multicast address will arrive at all

interfaces belonging to the multicast group.

IPv6 provides the following benefits

Larger address space for global reach

ability.

Simplified header for routing efficiency and

performance.

Deeper hierarchy and policies for network

architecture flexibility.

Efficient support for routing and route

aggregation.

Server less auto configuration, easier

renumbering, multi homing, and improved

plug and play support vi)Security with

mandatory IP Security (IPSec) support for

all IPv6 devices.

Improved support for Mobile IP and mobile

computing devices (direct-path). .

Enhanced multicast support with increased

addresses and efficient mechanism.

IPv6Deployment Strategies:

The key strategies used in deploying IPv6 at

the edge of a network involve carrying IPv6

traffic over the IPv4 network, allowing

isolated IPv6 domains to communicate with

each other before the full transition to a

native IPv6 backbone. It is also possible to

run IPv4 and IPv6 throughout the network,

from all edges through the core, or to

translate between IPv4 and IPv6 to allow

hosts communicating in one protocol to

communicate transparently with hosts

running the other protocol. All techniques

allow networks to be upgraded and IPv6

deployed incrementally with little to no

disruption of IPv4 services.


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The four key strategies for deploying IPv6

are as follows:

Deploying IPv6 over IPv4 tunnels: These

tunnels encapsulate the IPv6 traffic within

the IPv4 packets, and are primarily for

communication between isolated IPv6 sites

or connection to remote IPv6 networks over

an IPv4 backbone. The techniques include

using manually configured tunnels, generic

routing encapsulation (GRE) tunnels,semiautomatic tunnel mechanisms such as

tunnel broker services, and fully automatic

tunnel mechanisms such as IPv4-compatible

and 6to4.

Deploying IPv6 over dedicated data links:

This technique enables isolated IPv6

domains to communicate by using the same

Layer 2 infrastructure as for IPv4, but with

IPv6 using separate Frame Relay or ATM

PVCs, separate optical links, or dense Wave

Division Multiplexing (dWDM).

Deploying IPv6 over MPLS backbones:

This technique allows isolated IPv6 domains

to communicate with each other, but over an

MPLS IPv4 backbone. Multiple techniques

are available at different points in the

network, but each requires little change to

the backbone infrastructure or

reconfiguration of the core routers because

forwarding is based on labels rather than the

IP header itself. .

Deploying IPv6 using dual-stack backbones:

This technique allows IPv4 and IPv6

applications to coexist in a dual IP layer

routing backbone. All routers in the network

need to be upgraded to be dual-stack with

IPv4 communication using the IPv4 protocol

stack and IPv6 communication using the

IPv6 stack.

Comparitive Analysis Of IPV6 Major

Deployment Paths:

The following sections provide further

information on IPv6 deployment strategies

and protocol

translation mechanisms:y Deploying IPv6 over IPv4 Tunnelsy Deploying IPv6 over Dedicated Data

Links

y Deploying IPv6 over MPLSBackbones

y Deploying IPv6 Using Dual-StackBackbones

y Protocol Translation Mechanisms


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Tunneling is the encapsulation of IPv6

traffic within IPv4 packets so that they can

be sent over an IPv4 backbone, allowing

isolated IPv6 end systems and routers to

communicate without the need to upgrade

the IPv4 infrastructure that exists between

them. Tunneling is one of the key

deployment strategies for both service

providers and enterprises during the period

of IPv4 and IPv6 coexistence. Tunneling

allows service providers to offer an end-to-

end IPv6 service without major upgrades to

the infrastructure and without impacting

current IPv4 services.

Fig:8. Tunneling

Assessment Of Deployment Paths

Including Time Scale:

In the beginning of the 1990s, the IETF, the

organisation that develops the Internet

standards, started work on the successor of

the Internet Protocol (IP). IP is the protocol

that makes it possible for data packets to

travel over the Internet from one attached

computer to another. A decade later, the

specifications for the new standard (named

IP version 6, or IPv6) are almost, but still

not quite, complete. the most important

milestones in the IPv6 standardisation

process. In 1992: IETF issues Call for IPng

proposals. The IETF started its effort to

select a successor to IPv4 in late 1990 when

projections indicated that the Internet

address space would become an increasingly

limited resource. This looming lack IP

address space was from the very beginning

the most important driving force behind the

development of IPv6. In July 1992, the IETF

issued a Call for Proposals for a next-

generation Internet Protocol, to solve the

address space problem. Several proposals

sprung up, with a wide range in

revolutionariness. Late 1993, the IETF

formed the IP (IP next generation) Area

(later transformed into the IPng Working

Group to investigate the various proposals

and recommend how to proceed. This IETF


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Area produced an IPng technical criteria

document, RFC 1726 that was used in order

to evaluate the three remaining proposals.

The main criteria named in this process are:

-Architectural simplicity (don't include

functions into IP that are better located

elsewhere)

- Scale

- Performance

- Transition

- Configuration ease

- Security

- Service classes

In RFC 1752 the then remaining IPng

proposals were evaluated. One of the

proposals(SIPP), with a number of

modifications, including the doubling of the

proposed address length from 64 to 128 bits,

was chosen as a basis for IPng.

1995: RFC-1883 -- Internet Protocol,

Version 6 (IPv6) specification

Based on SIPP, RFC 1883 was the first

specification carrying the name IPv6. This

specification has the IETF status of

"Proposed Standard". Accompanying and

following this specification, several other

RFC's were issued, specifying the IPv6

addressing architecture, changes to related

protocols, network autoconfiguration,

security and IPv4-IPv6 transition

mechanisms.

1998: RFC-2460 - Internet Protocol, Version

6 (IPv6) specification

It took until December 1998 for the RFC-

1883 based specifications to evolve into

RFC 2460 (and accompanying RFCs), an

IETF "Draft Standard", one step further on

the way to the status of "Internet Standard".

At the moment, the IPv6 specification is still

incomplete: some parts that need to be

specified in accompanying documents are

not yet finished. There is still considerable

discussion, especially about the IPv6

addressing architecture.

2001: First commercials IPv6 offerings

Only very recently Cisco Systems, the

worlds largest maker of data networking

equipment, announced a range of software

for its routers using IPv6. It will be available

at the end of May. Microsoft only expects

full commercial support for IPv6 in its

Windows operating system in 2002. Japans

NTT was the first service provider to offer

commercial IPv6 services, undoubtedly

pushed by the Japanese government, which

pledged to adopt IPv6 by 2005. Zama

Networks, based in Seattle, was the first

U.S. service provider to offer commercial

IPv6 services, starting operations in the

spring of 2001. The IETF is supposed to be

able to quickly find working solutions to

engineering problems. But the problems are:


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Proliferation of requirements:Some say that

the IPv6 standard has become too

widespread and too complicated. This would

presume that the expectations or

requirements for the next-generation IP

protocol have been extending during the

standardisation process. Obviously, when

extra requirements are constantly added

during the process, the destination will never

be reached.

No time pressure:Seeing that the first

commercials products supporting the IPv6

standard have only come out recently, it

seems reasonable to assume that there has

been little pressure on the IPng working

group to make haste. After all, the IPv4

address space is expected to suffice at least

until 2005. Even though products are

available now, vendors have seen almost no

interest from their enterprise customers.

Academics and other outsiders: Has the

openness of the IETF meetings and

procedures given too much opportunity to

relative outsiders,

especially from academia, to interfere in the

process, nit-pick on details and try to make

the protocol of a universal quality, opposed

to the usual IETF motto of rough consensus

and running code? Have political motives,

so despised by IETF regulars, seeped in with

representatives from hardware vendors. In

other words, have people from other

backgrounds than usual at earlier IETF

processes causes the retardation.

These are the problems and issues that deals

with the deployment of IPv6 on the

timescale.


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References:

Coffey, Steve. 1998. Internet Advertising

Bureau. America : American Academy Of

Advertising, 1998.

Geoff .Huston andTelstra ,the internet

protocol journalvolume-6,number4.

James F. Kurose, Keith W. Ross. 2010.

Computer Nertworks - ATop Down

Approach. s.l. : Pearson Edition, 2010.

http://royal.pingdom.com/2010/01/22/intern

et-2009-in-numbers/

Geoff. Huston IPv4 Address Depletion,

The Internet Protocol Journal - Volume 10,

No. 3, at APNIC meeting in NEWDELHI.

Current status of IPV4

address,http://www.potaroo.net/tools/ipv4/in

dex.html

http://www.internetworldstats.com/stats7.ht

m

IPV4 Exhaustion counter,

http://www.potaroo.net/tools/ipv4/index.htm

l

ARIN Board Advises Internet Community

on Migration to IPv6 Mon, 21 May

2007,http://www.arin.net/announcements/20

070521.html

Asia-Pacific Network Information Centre

(APNIC) (2007-06-26). "JPNIC releases

statement on IPv4 consumption

Internet protocol journal,by tony hain of

cisco systems.

JPNIC releases statement on IPv4

consumption, About IPv4 addressexhaustion in Internet Registries,

http://www.apnic.net/news/2007/0626.html


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