Wireless
synchronisation – you caneliminate wires along with
improving safety with Bluetooth. You need not worry about carrying
connection cables while travelling with your laptop or other wireless
devices.
Economical -
The Bluetooth technology is cheap to implement for
the companies resulting in lower costs hence, these savings are passed
from the company to you making it economical.
Universally
accepted - Bluetooth
technology is accepted world wide, with it gaining so much popularity, you
can rely on it for years to come with an advent of more and more devices
started to use Bluetooth technology.
Automatic – setting up
Bluetooth connectivity is automatic Bluetooth and doesn’t need
professionals. When two or more devices enter a range of up to 30
feet of each other the communication automatically begins between them.
Upgradeable - Upgradeable
Bluetooth standard versions of Bluetooth in the offer various new
advantages and backward compatibility with older versions.
Standard
protocol
- Bluetooth is standardized wireless guarantees the high level of
compatibility among devices. Bluetooth devices connect to each other
irrespective of their model.
Instant PAN
(Personal Area Network) - You can have your own personal are
network for sharing data among your group consisting of up to seven Bluetooth
devices within a range of up to 30 feet.
Faster data
and voice Sharing – you can share data and voice communications via
Bluetooth with compatible devices connected to it.
Simplifies
communication while driving – companies like parrot manufactures
Bluetooth car kits resolving the audio and communication issues arising
while driving, as Bluetooth simplifies talking and listening music on your
cell phone while driving.
Avoids
interference from other wireless devices - Bluetooth
devices avoid interference from other wireless devices with the usage of
technique known as frequency hopping, and low power wireless signals.
Low power
consumption
- Bluetooth with the help of low power signals technology requires very
less energy reducing the battery consumption or electrical power.
Best
alternative to data transfer - in case of corruptflash/pen
drives or DVD/CD ROM. It has helped a lot of times when I forgot my pen
drive.
Peering is a voluntary interconnection of
administratively separate Internetnetworks for the purpose of exchanging traffic between
the customers of each network. The pure definition of peering is
settlement-free or "sender keeps all," meaning that neither party
pays the other for the exchanged traffic, instead, each derives revenue from
its own customers. Marketing and commercial pressures have led to the word
peering routinely being used when there is some settlement involved, even
though that is not the accurate technical use of the word. The phrase
"settlement-free peering" is sometimes used to reflect this reality
and unambiguously describe the pure cost-free peering situation.
Peering requires physical interconnection of the networks, an exchange of routing
information through the Border Gateway Protocol (BGP) routing
protocol and is often accompanied by peering agreements of varying formality,
from "handshake" to thick contracts.
How peering
works
The Internet is a collection of separate and distinct networks, each one
operating under a common framework of globally unique IP addressing
and global BGP
routing.
The relationships between these networks are generally described by one of
the following three categories:
Transit (or pay) - You pay money (or settlement)
to another network for Internet access (or transit).
Peer (or swap)
- Two networks exchange traffic between each other's customers freely, and
for mutual benefit.
Customer
(or sell) - Another network pays you money to provide them with
Internet access.
Furthermore, in order for a network to reach any specific other network on
the Internet,
it must either:
Sell transit
(or Internet access) service to that network (making them a 'customer'),
Peer
directly with that network, or with a network who sells transit service to
that network, or
Pay
another network for transit service, where that other network must in turn
also sell, peer, or pay for access.
The Internet is based on the principle of global reachability
(sometimes called end-to-end reachability), which means that any
Internet user can reach any other Internet user as though they were on the same
network. Therefore, any Internet connected network must by definition either
pay another network for transit, or peer with every other network who also does
not purchase transit.
Motivations
for peering
Peering involves two networks coming together to exchange traffic with each
other freely, and for mutual benefit. This 'mutual benefit' is most often the
motivation behind peering, which is often described solely by "reduced
costs for transit services". Other less tangible motivations can include:
Increased redundancy (by reducing
dependence on one or more transit providers).
Increased capacity for extremely
large amounts of traffic (distributing traffic across many networks).
Increased routing control over your
traffic.
Improved performance (attempting to
bypass potential bottlenecks with a "direct" path).
Improved perception of your network
(being able to claim a "higher tier").
Ease of requesting for emergency aid
(from friendly peers).
Physical
interconnections for peering
Scheme of interconnection
and peering of autonomous systems
The physical interconnections used for peering are categorized into two
types:
Public peering - Interconnection
utilizing a multi-party shared switch fabric such as an Ethernet
switch.
Private peering - Interconnection
utilizing a point-to-point link between two parties.
Public
peering
Public peering is accomplished across a Layer 2 access technology,
generally called a shared fabric. At these locations, multiple carriers
interconnect with one or more other carriers across a single physical port.
Historically, public peering locations were known as network access points (NAPs); today they are
most often called exchange points or Internet exchanges
("IXP" or "IX"). Many of the largest exchange points in the
world can have hundreds of participants, and some span multiple buildings and colocation
facilities across a city.
Since public peering allows networks interested in peering to interconnect with
many other networks through a single port, it is often considered to offer
"less capacity" than private peering, but to a larger number of
networks. Many smaller networks, or networks who are just beginning to peer,
find that public peering exchange points provide an excellent way to meet and
interconnect with other networks who may be open to peering with them. Some
larger networks utilize public peering as a way to aggregate a large number of
"smaller peers", or as a location for conducting low-cost "trial
peering" without the expense of provisioning private peering on a
temporary basis, while other larger networks are not willing to participate at
public exchanges at all.
A few exchange points, particularly in the United States, are operated by
commercial carrier-neutral third parties. These operators typically go to great
lengths to promote communication and encourage new peering, and will often
arrange social events for these purposes.
Private
peering
Private peering is the direct interconnection between only two networks,
across a Layer 1 or 2 medium that offers dedicated capacity that is not shared
by any other parties. Early in the history of the Internet, many private peers
occurred across 'telco' provisioned SONET circuits between individual carrier-owned facilities.
Today, most private interconnections occur at carrier
hotels or carrier neutral colocation facilities, where a direct
crossconnect can be provisioned between participants within the same building,
usually for a much lower cost than telco circuits.
Most of the traffic on the Internet, especially traffic between the largest
networks, occurs via private peering. However, because of the resources
required to provision each private peer, many networks are unwilling to provide
private peering to "small" networks, or to "new" networks
who have not yet proven that they will provide a mutual benefit.
Peering
agreements/contracts
Throughout the history of the Internet, there have been a spectrum of kinds
of agreements between peers, ranging from handshake deals to peering contracts
which may be required by one or both sides. Such a contract sets
forth the details of how traffic is to be exchanged, along with a list of
expected activities which may be necessary to maintain the peering
relationship, a list of activities which may be considered abusive and result
in termination of the relationship, and details concerning how the relationship
can be terminated. Detailed contracts of this type are typically used between
the largest ISPs, and the ones operating in the most heavily-regulated
economies, accounting for about 1-2% of peering relationships overall.
History of
peering
The first Internet exchange point was the Commercial
Internet Exchange (CIX), formed by Alternet/UUNET (now Verizon Business), PSI,
and CERFNET to exchange traffic without regard for whether the traffic complied
with the acceptable use policy (AUP) of the NSFNet or
ANS' interconnection policy. The CIX infrastructure consisted of a single
router, managed by PSI, and was initially located in Santa Clara, California.
Paying CIX members were allowed to attach to the router directly or via leased
lines. After some time, the router was also attached to the Pacific Bell SMDS
cloud. The router was later moved to the Palo Alto Internet Exchange, or PAIX,
which was developed and operated by Digital Equipment Corporation (DEC).
Another early exchange point was Metropolitan Area
Ethernet, or MAE, in Tysons Corner, Virginia. When
the United States government decided to de-fund the NSFNET backbone,
Internet exchange points were needed to replace its function, and initial governmental
funding was used to aid the MAE and bootstrap three other exchanges, which they
dubbed NAPs, or "Network Access Points," in accordance with the
terminology of the National Information Infrastructure document. All four are
now defunct or no longer functioning as Internet exchange points:
As the Internet grew, and traffic levels increased, these NAPs became a network bottleneck. Most of the early NAPs
utilized FDDI
technology, which provided only 100 Mbit/s of capacity to each participant. Some of
these exchanges upgraded to ATM technology, which provided OC-3 (155 Mbit/s) and OC-12 (622 Mbit/s) of
capacity.
Other prospective exchange point operators moved directly into offering
Ethernet technology, such as gigabit
Ethernet (1000 Mbit/s), which quickly became the predominant choice for
Internet exchange points due to the reduced cost and increased capacity
offered. Today, almost all significant exchange points operate solely over
Ethernet, and most of the largest exchange points offer ten gigabit Ethernet
(10,000 Mbit/s) service.
During the dot-com boom, many exchange point and carrier
neutral colocation providers had plans to build as many as 50 locations to
promote carrier interconnection in the United States alone. Essentially all of
these plans were abandoned following the dot-com bust, and today it is considered
both economically and technically infeasible to support this level of
interconnection among even the largest of networks.
Depeering
By definition, peering is the voluntary and free exchange of traffic
between two networks, for mutual benefit. If one or both networks believes that
there is no longer a mutual benefit, they may decide to cease peering: this is
known as depeering. Some of the reasons why one network may wish to
depeer another include:
A desire that the other network pay
settlement, either in exchange for continued peering or for transit
services.
A belief that the other network is
"profiting unduly" from the settlement free interconnection.
Concern over traffic ratios,
which related to the fair sharing of cost for the interconnection.
A desire to peer with the upstream
transit provider of the peered network.
Abuse of the interconnection by the
other party, such as pointing default or utilizing the peer for
transit.
Instability of the peered network,
repeated routing leaks, lack of response to network abuse issues, etc.
The inability or unwillingness of the
peered network to provision additional capacity for peering.
The belief that the peered network is
unduly peering with your customers.
Various external political factors
(including personal conflicts between individuals at each network).
In some situations, networks who are being depeered have been known to
attempt to fight to keep the peering by intentionally breaking the connectivity
between the two networks when the peer is removed, either through a deliberate
act or an act of omission. The goal is to force the depeering network to have
so many customer complaints that they are willing to restore peering. Examples
of this include forcing traffic via a path that does not have enough capacity to
handle the load, or intentionally blocking alternate routes to or from the
other network.
Modern
peering
Peering locations
The modern Internet operates with significantly more peering locations than
at any time in the past, resulting in improved performance and better routing
for the majority of the traffic on the Internet. However, in the interests of
reducing costs and improving efficiency, most networks have attempted to
standardize on relatively few locations within these individual regions where they
will be able to quickly and efficiently interconnect with their peering
partners.
The primary locations for peering within the United States are generally
considered to be.
San Francisco Bay Region (San Jose
CA, Palo Alto CA, Santa Clara CA, San Francisco CA)
Washington DC / Northern Virginia
Region (Washington, DC, Ashburn VA, Reston VA, Vienna VA)
New York City Region (New York NY,
Newark NJ)
Chicago Region (Chicago IL)
Los Angeles Region (Los Angeles, CA)
Dallas Region (Dallas, TX, Plano, TX,
Richardson, TX)
Miami, FL
Seattle, WA
For international traffic, the most important locations for peering are
generally considered to be
Europe;
Amsterdam, Netherlands
London, United Kingdom
Frankfurt, Germany
Rest of the World;
Tokyo, Japan
Hong Kong, China
Seoul, South Korea
Singapore
Exchange
points
The largest individual exchange points in the world are AMS-IX in Amsterdam, followed by DE-CIX in Frankfurt
Germany and LINX in London. The next largest exchange
point is generally considered to be JPNAP in Tokyo, Japan. The United
States, with a historically larger focus on private peering and commercial
public peering, has a much smaller amount of traffic on public peers compared
to other regions which operate non-profit exchange points. The combined
exchange points in multiple cities operated by Equinix are
generally considered to be the largest and most important, followed by the PAIX facilities which
are operated by Switch and Data. Other important but smaller
exchange points include LIPEX and LONAP in London UK, NYIIX in New York, and NAP of the Americas in Miami,
Florida.
URLs to some public traffic statistics of exchange points include:
A great deal of the complexity in the BGP routing protocol
exists to aid the enforcement and fine-tuning of peering and transit
agreements. BGP allows operators to define a policy that determines where
traffic is routed. Three things commonly used to determine routing are
local-preference, multi exit discriminators
(MEDs) and AS-Path. Local-preference is used
internally within a network to differentiate classes of networks. For example,
a particular network will have a higher preference set on internal and customer
advertisements. Settlement free peering is then configured to be preferred over
paid IP
transit.
Networks that speak BGP to each other can engage in multi exit
discriminator exchange with each other, although most do not. When networks
interconnect in several locations, MEDs can be used to reference that network's
interior gateway protocol cost. This
results in both networks sharing the burden of transporting each others traffic
on their own network (or cold potato). Hot-potato or nearest-exit routing, which is typically the
normal behavior on the Internet, is where traffic destined to another network
is delivered to the closest interconnection point.
Law and
policy
Internet interconnection is not regulated in the same way that public telephone
network interconnection is regulated. Nevertheless, Internet interconnection
has been the subject of several areas of federal policy. Perhaps the most
dramatic example of this is the attempted MCI Worldcom/Sprint
merger. In this case, the Department of Justice signaled
that it would move to block the merger specifically because of the impact of
the merger on the Internet backbone market. In 2001, the Federal Communications Commission's
advisory committee, the Network Reliability and Interoperability Council recommended
that Internet backbones publish their peering policies, something that they had
been hesitant to do beforehand. The FCC has also reviewed competition in the
backbone market in its Section 706 proceedings which review whether advanced telecommunications are being provided to all Americans
in a reasonable and timely manner.
Finally, Internet interconnection has become an issue in the international
arena under something known as the International Charging Arrangements for
Internet Services (ICAIS).[11] In the
ICAIS debate, countries underserved by Internet backbones have complained that
it is unfair that they must pay the full cost of connecting to an Internet
exchange point in a different country, frequently the United States. These
advocates argue that Internet interconnection should work like international
telephone interconnection, with each party paying half of the cost.[12] Those
who argue against ICAIS point out that much of the problem would be solved by
building local exchange points. A significant amount of the traffic, it is
argued, that is brought to the US and exchanged then leaves the US, using US
exchange points as switching offices but not terminating in the US.[13] In some
worst-case scenarios, traffic from one side of a street is brought to all the
way to Miami, exchanged, and then returned to another side of the street.
Countries with liberalized telecommunications and open markets, where
competition between backbone providers occurs, tend to oppose ICAIS.
Password cracking is the process of recovering secret passwords from data that
has been stored in or transmitted by a computer system. A common approach is to
repeatedly try guesses for the password.
Most passwords can be cracked by using following techniques :
1) Hashing :- Here we will
refer to the one way function (which may be either an encryption function or
cryptographic hash) employed as a hash and its output as a hashed password.
If a system uses a reversible function to obscure stored passwords, exploiting
that weakness can recover even 'well-chosen' passwords.
One example is the LM hash that Microsoft Windows uses by default to store user
passwords that are less than 15 characters in length.
LM hash breaks the password into two 7-character fields which are then hashed
separately, allowing each half to be attacked separately.
Hash functions like SHA-512, SHA-1, and MD5 are
considered impossible to invert when used correctly.
2) Guessing :- Many
passwords can be guessed either by humans or by sophisticated cracking programs
armed with dictionaries (dictionary based) and the user's personal information.
Not surprisingly, many users choose weak passwords, usually one related to
themselves in some way. Repeated research over some 40 years has demonstrated
that around 40% of user-chosen passwords are readily guessable by programs.
Examples of insecure choices include:
* blank (none)
* the word "password", "passcode", "admin" and
their derivatives
* the user's name or login name
* the name of their significant other or another person (loved one)
* their birthplace or date of birth
* a pet's name
* a dictionary word in any language
* automobile licence plate number
* a row of letters from a standard keyboard layout (eg, the qwerty keyboard --
qwerty itself, asdf, or qwertyuiop)
* a simple modification of one of the preceding, such as suffixing a digit or
reversing the order of the letters.
and so on....
In one survery of MySpace passwords which had been phished, 3.8 percent of
passwords were a single word found in a dictionary, and another 12 percent were
a word plus a final digit; two-thirds of the time that digit was.
A password containing both uppercase &
lowercase characters, numbers and special characters too; is a strong
password and can never be guessed.
3) Default Passwords :-
A moderately high number of local and online applications have inbuilt default
passwords that have been configured by programmers during development stages of
software. There are lots of applications running on the internet on which
default passwords are enabled. So, it is quite easy for an attacker to enter
default password and gain access to sensitive information. A list containing
default passwords of some of the most popular applications is available on the
internet.
Always disable or change the applications' (both online
and offline) default username-password pairs.
4) Brute Force :- If all
other techniques failed, then attackers uses brute force password cracking
technique. Here an automatic tool is used which tries all possible combinations
of available keys on the keyboard. As soon as correct password is reached it
displays on the screen.This techniques takes extremely long time to complete,
but password will surely cracked.
Long is the password, large is the time taken to brute
force it.
5) Phishing :- This is
the most effective and easily executable password cracking technique which is
generally used to crack the passwords of e-mail accounts, and all those
accounts where secret information or sensitive personal information is stored
by user such as social networking websites, matrimonial websites, etc.
Phishing is a technique in which the attacker creates the fake login screen and
send it to the victim, hoping that the victim gets fooled into entering the
account username and password. As soon as victim click on "enter" or
"login" login button this information reaches to the attacker using
scripts or online form processors while the user(victim) is redirected to home
page of e-mail service provider.
Never give reply to the messages which are demanding
for your username-password, urging to be e-mail service provider.
It is possible to try to obtain the passwords through other different methods,
such as social engineering, wiretapping, keystroke logging, login spoofing,
dumpster diving, phishing, shoulder surfing, timing attack, acoustic
cryptanalysis, using a Trojan Horse or virus, identity management system
attacks (such as abuse of Self-service password reset) and compromising host
security.
However, cracking usually designates a guessing attack.
