[AI] (Tech Dose of the Day) VLAN, Folksonomy, Blu-ray Disc, Phishing, DYA, Semantic Web, LAMP and much much more!

vishnu ramchandani vishnuhappy at yahoo.com
Thu Jan 24 23:11:32 EST 2008

Tech Dose of the Day

VLAN, Folksonomy, Blu-ray Disc, Phishing, DYA (Dynamic
Architecture), Semantic Web, LAMP, etc.

Contributed by M&E (Media & Entertainment Delivery)
Group (MphasiS Software Services)

What is VLAN?
A Virtual LAN, commonly known as a VLAN, is a group of
hosts with a common set of requirements that
communicate as if they were attached to the same wire,
regardless of their physical location. A VLAN has the
same attributes as a physical LAN, but it allows for
end stations to be grouped together even if they are
not located on the same LAN segment. Network
reconfiguration can be done through software instead
of physically relocating devices. 
Why are VLANs required?
In a legacy network, users were assigned to networks
based on geography and were limited by physical
topologies and distances. By using VLAN, one can
logically group networks and is no longer restricted
by physical distance. This includes high-speed
technologies such as:
Asynchronous Transfer Mode (ATM), Fiber Distributed
Data Interface (FDDI), Fast Ethernet, Gigabit Ethernet
and 10-Gigabit Ethernet.
By using VLAN, one can control traffic patterns and
react quickly to relocations. VLANs provide the
flexibility to adapt to changes in network
requirements and allow for simplified administration.
Additionally, VLANs provide an increased security
measure and the ability to limit broadcasts.
The protocol used in configuring virtual LANs is IEEE
Virtual LANs operate at Layer 2 (the data link layer)
of the OSI model.
VTP (VLAN Trunking Protocol) maintains VLAN
configuration consistency across the entire network.
VTP uses Layer 2 trunk frames to manage the addition,
deletion, and renaming of VLANs on a network-wide
basis from a centralized switch in the VTP server
mode. VTP is responsible for synchronizing VLAN
information within a VTP domain and reduces the need
to configure the same VLAN information on each switch.
VTP minimizes the possible configuration
inconsistencies that arise when changes are made.
These inconsistencies can result in security
violations, because VLANs can crossconnect when
duplicate names are used. They also could become
internally disconnected when they are mapped from one
LAN type to another, for example, Ethernet to ATM LANE
ELANs or FDDI 802.10 VLANs. VTP provides a mapping
scheme that enables seamless trunking within a network
employing mixed-media technologies.
VTP provides the following benefits:
VLAN configuration consistency across the network,
Mapping scheme that allows a VLAN to be trunked over
mixed media, Accurate tracking and monitoring of
VLANs, Dynamic reporting of added VLANs across the
network and Plug-and-play configuration when adding
new VLANs.
Further References 
Wikipedia - 
Some more info - 

What is Folksonomy? 
Folksonomy is also known as collaborative tagging,
social classification, social indexing and social
tagging.  Folksonomy is the practice and method of
collaboratively creating and managing tags to annotate
and categorize content.
A folksonomy is a user-generated taxonomy used to
categorize and retrieve web content such as web
resources, online photographs and web links, using
open-ended labels called tags. A folksonomy is most
notably contrasted from a taxonomy in that the authors
of the labeling system are often the main users (and
sometimes originators) of the content to which the
labels are applied. The labels are commonly known as
tags and the labeling process is called tagging. Tags
help to improve search engine effectiveness because
content is categorized using a familiar, accessible,
and shared vocabulary.
Folksonomy allows users to tag their favorite web
resources with their chosen words or phrases selected
from natural language. These tags (also called
concepts, categories, facets or entities) can be used
to classify web resources and to express users'
preferences. Folksonomy is a classification of the
users, by the users and for the users. The most
popular, widely used folksonomy-based systems are:
1.      Del.icio.us: 
2.      CiteULike:
3.      Connotea:

4.      Flickr:
Folksonomies became popular on the Web around 2004
with social software applications such as social
bookmarking or annotating photographs. Websites that
support tagging and the principle of folksonomy are
referred to in the context of Web 2.0 because
participation is very easy and tagging data is used in
new ways to find information. For example, tag clouds
are frequently used to visualize the most used tags of
a folksonomy. The term folksonomy is also used to
denote only the set of tags that are created in social
Typically, folksonomies are Internet-based, although
they are also used in other contexts. Folksonomic
tagging is intended to make a body of information
increasingly easy to search, discover, and navigate
over time. A well-developed folksonomy is ideally
accessible as a shared vocabulary that is both
originated by, and familiar to, its primary users.
Folksonomies arise in Web-based communities where
provisions are made at the site level for creating and
using tags. These communities are established to
enable Web users to label and share user-generated
content, such as photographs, or to collaboratively
label existing content, such as Web sites, books,
works in the scientific and scholarly literatures, and
blog entries.
What are its problems?
Four main problems of folksonomy tagging are plurals,
polysemy, synonymy, and depth (specificity) of
Plurals: Plurals and parts of speech and spelling can
undermine a tagging system. For example, if tags Cat
and Cats are distinct, then a query for one will not
retrieve both, unless the intelligent search system
has the capability to perform such replacements built
into it.
Polysemy: Polysemy refers to a word that has two or
more similar meanings. "Poly" means 'many', and "semy"
means 'meanings'.
Synonymy: Synonymy, different words with similar or
identical meanings, presents a greater problem for
tagging systems because inconsistency among the terms
used in tagging can make it very difficult for a
searcher to be sure that all the relevant items have
been found.
Depth (specificity) of tagging: Specificity means how
specific should the user (classifier) be in
translating a concept into tag(s)? Web resources can
be tagged to varying levels of specificity, from very
broad subjects taken only from the title and abstract
to the paragraph level. The depth of tags refers to
how many tags there are, relative to a web resource in
the system.
Further References 
Wikipedia : 
Folksonomies - Tidying up tags : 

Blu-ray Disc  
What is Blu-ray Disc? 
Blu-ray, also known as Blu-ray Disc (BD), is the name
of a next-generation optical disc format jointly
developed by the Blu-ray Disc Association (BDA), a
group of the world's leading consumer electronics,
personal computer and media manufacturers (including
Apple, Dell, Hitachi, HP, JVC, LG, Mitsubishi,
Panasonic, Pioneer, Philips, Samsung, Sharp, Sony, TDK
and Thomson). The format was developed to enable
recording, rewriting and playback of high-definition
video (HD), as well as storing large amounts of data.
The format offers more than five times the storage
capacity of traditional DVDs and can hold up to 25GB
on a single-layer disc and 50GB on a dual-layer disc.
This extra capacity combined with the use of advanced
video and audio codecs will offer consumers an
unprecedented HD experience.
While current optical disc technologies such as DVD,
DVD±R, DVD±RW, and DVD-RAM rely on a red laser to read
and write data, the new format uses a blue-violet
laser instead, hence the name Blu-ray. Despite the
different type of lasers used, Blu-ray products can
easily be made backwards compatible with CDs and DVDs
through the use of a BD/DVD/CD compatible optical
pickup unit. The benefit of using a blue-violet laser
(405nm) is that it has a shorter wavelength than a red
laser (650nm), which makes it possible to focus the
laser spot with even greater precision. This allows
data to be packed more tightly and stored in less
space, so it's possible to fit more data on the disc
even though it's the same size as a CD/DVD. This
together with the change of numerical aperture to 0.85
is what enables Blu-ray Discs to hold 25GB/50GB.
Blu-ray is currently supported by more than 180 of the
world's leading consumer electronics, personal
computer, recording media, video game and music
companies. The format also has broad support from the
major movie studios as a successor to today's DVD
format. In fact, seven of the eight major movie
studios (Disney, Fox, Warner, Paramount, Sony,
Lionsgate and MGM) have released movies in the Blu-ray
format and five of them (Disney, Fox, Sony, Lionsgate
and MGM) are releasing their movies exclusively in the
Blu-ray format. Many studios have also announced that
they will begin releasing new feature films on Blu-ray
Disc day-and-date with DVD, as well as a continuous
slate of catalog titles every month.
What is its usefulness, advantages and disadvantages?
Blu-ray Disc is a high-density optical disc format for
the storage of digital information, including
high-definition video. A single-layer Blu-ray disc,
which is roughly the same size as a DVD, can hold up
to 27 GB of data -- that's more than two hours of
high-definition video or about 13 hours of standard
video. A double-layer Blu-ray disc can store up to 50
GB, enough to hold about 4.5 hours of high-definition
video or more than 20 hours of standard video. And
there are even plans in the works to develop a disc
with twice that amount of storage double-layer Blu-ray
disc can store up to 50 GB, enough to hold about 4.5
hours of high-definition video or more than 20 hours
of standard video. And there are even plans in the
works to develop a disc with twice that amount of
storage. Blu-ray is currently supported by more than
180 of the world's leading consumer electronics,
personal computer, recording media, video game and
music companies. One of the benefits of Blu-Ray
technology is that because data is so close together,
early types of Blu-Ray discs would be contaminated by
slight scratches. However, a new coating has been
developed that makes Blu-Ray discs extremely difficult
to scratch.
 Some of the Advantages of Blu-ray Disc over HD-DVD :-
• The first is capacity. Because Blu-ray utilizes a
lens with a greater numerical aperture (NA) than
HD-DVD, the laser spot can be focused with greater
precision to fit more data on the same size disc. This
allows Blu-ray to hold 25GB per layer (50GB on a
dual-layer disc), whereas HD-DVD can only hold 15GB
per layer (30GB on a dual-layer disc). Blu-ray has
also adopted a higher data transfer rate for video and
audio (54Mbps vs 36.55Mbps). The greater capacity and
data transfer rates for Blu-ray will allow the movie
studios to release their movies with higher quality
video and audio than the HD-DVD format.
• The second is content. The Blu-ray format has
received broad support from the major movie studios as
a successor to today's DVD format. Seven of the eight
major movie studios (Warner, Paramount, Fox, Disney,
Sony, MGM and Lionsgate) have released titles for
Blu-ray, whereas HD-DVD only has support from three
major movie studios (Warner, Paramount and Universal).
This is an important difference because some of the
studios might only support one of the formats, so you
won't be able to get your favourite movies in the
other format. Choosing the format with the most
content support minimizes this risk.
• The third is hardware support. The Blu-ray format
has broad support from the world's leading consumer
electronics, personal computer and media
manufacturers, including Sony, Panasonic, Philips,
Samsung, Pioneer, Sharp, JVC, Hitachi, Mitsubishi,
TDK, Thomson, LG, Apple, HP and Dell. The Blu-ray
format will also be supported in the next-generation
PlayStation 3 (PS3) video game console. This means
that you will have a lot of choice when it comes to
players and hardware. The HD-DVD format has far fewer
supporters, so the amount of players and hardware will
be very limited.
Some of the Disadvantages :-
• The disadvantages to Blu-Ray discs are that they are
quite expensive. For instance, players are selling at
about the $1,000 mark and DVD discs will be more
expensive than their standard DVD counterparts.
• Another disadvantage is that since there are two
standards, both Blu-Ray and HD, most people are
sitting on the sidelines to see who the winner is.
Because Blu-Ray has been developed in part with Sony,
Sony has included DRM or digital rights management
that will make it more difficult for people to place
shift and time shift their content.
Further References 

What is Phishing?
Phishing is an attempt to criminally and fraudulently
acquire sensitive information, such as usernames,
passwords and credit card details, by masquerading as
a trustworthy entity in an electronic communication.
eBay, PayPal and online banks are common targets.
Phishing is typically carried out by email or instant
messaging and often directs users to enter details at
a website, although phone contact has also been used.
Phishing is an example of social engineering
techniques used to fool users. Phishing attacks use
both social engineering and technical subterfuge to
steal consumers' personal identity data and financial
account credentials. Social-engineering schemes use
'spoofed' e-mails to lead consumers to counterfeit
websites designed to trick recipients into divulging
financial data such as credit card numbers, account
usernames, passwords and social security numbers.
Hijacking brand names of banks, e-retailers and credit
card companies, phishers often convince recipients to
respond. Technical subterfuge schemes plant crime ware
onto PCs to steal credentials directly, often using
Trojan keylogger spyware.
Phishing techniques:
Link manipulation
Most methods of phishing use some form of technical
deception designed to make a link in an email (and the
spoofed website it leads to) appear to belong to the
spoofed organization. Misspelled URLs or the use of
sub domains are common tricks used by phishers, such
as this example URL,
.. Another common trick is to make the anchor text for
a link appear to be valid, when the link actually goes
to the phishers' site. An old method of spoofing used
links containing the '@' symbol, originally intended
as a way to include a username and password (contrary
to the standard). For example, the link
 might deceive a casual observer into believing that
it will open a page on
whereas it actually directs the browser to a page on
members.tripod.com, using a username of
the page opens normally, regardless of the username
supplied. Such URLs were disabled in Internet
Explorer, while the Mozilla and Opera web browsers
opted to present a warning message and give the option
of continuing to the site or cancelling. A further
problem with URLs has been found in the handling of
Internationalized Domain Names (IDN) in web browsers,
that might allow visually identical web addresses to
lead to different, possibly malicious, websites.
Despite the publicity surrounding the flaw, known as
IDN spoofing or a homograph attack, no known phishing
attacks have yet taken advantage of it. Phishers have
taken advantage of a similar risk, using open URL
redirectors on the websites of trusted organizations
to disguise malicious URLs with a trusted domain.
Filter evasion
Phishers have used images instead of text to make it
harder for anti-phishing filters to detect text
commonly used in phishing emails. 
Website forgery:
Once the victim visits the website the deception is
not over. Some phishing scams use JavaScript commands
in order to alter the address bar. This is done either
by placing a picture of a legitimate URL over the
address bar, or by closing the original address bar
and opening a new one with the legitimate URL. An
attacker can even use flaws in a trusted website's own
scripts against the victim. These types of attacks
(known as cross-site scripting) are particularly
problematic, because they direct the user to sign in
at their bank or service's own web page, where
everything from the web address to the security
certificates appears correct. In reality, the link to
the website is crafted to carry out the attack,
although it is very difficult to spot without
specialist knowledge. Just such a flaw was used in
2006 against PayPal. A Universal Man-in-the-middle
Phishing Kit, discovered by RSA Security, provides a
simple-to-use interface that allows a phisher to
convincingly reproduce websites and capture log-in
details entered at the fake site.
Phone phishing:
Not all phishing attacks require a fake website.
Messages that claimed to be from a bank told users to
dial a phone number regarding problems with their bank
accounts. Once the phone number (owned by the phisher,
and provided by a Voice over IP service) was dialed,
prompts told users to enter their account numbers and
PIN. Voice phishing sometimes uses fake caller-ID data
to give the appearance that calls come from a trusted
Phishing examples:
PayPal phishing example
An example of a phishing email targeted at PayPal
users.In an example PayPal phish (right), spelling
mistakes in the email and the presence of an IP
address in the link (visible in the tooltip under the
yellow box) are both clues that this is a phishing
attempt. Another giveaway is the lack of a personal
greeting, although the presence of personal details
would not be a guarantee of legitimacy.
How can this be prevented? 
There are several different techniques to combat
phishing, including legislation and technology created
specifically to protect against phishing.
Social responses:
One strategy for combating phishing is to train people
to recognize phishing attempts, and to deal with them.
Education can be promising, especially where training
provides direct feedback.
Technical responses:
Anti-phishing measures have been implemented as
features embedded in browsers, as extensions or
toolbars for browsers, and as part of website login
The following are some of the main approaches to the
• Helping to identify legitimate sites
• Since phishing is based on impersonation, preventing
it depends on some reliable way to determine a
website's real identity. For example, some
anti-phishing toolbars display the domain name for the
visited website.
Browsers alerting users to fraudulent websites.
Another popular approach to fighting phishing is to
maintain a list of known phishing sites and to check
websites against the list.
Augmenting password logins:
The Bank of America's website is one of several that
ask users to select a personal image, and display this
user-selected image with any forms that request a
Eliminating phishing mail:
Spam filters can reduce the number of phishing emails
that reach their addressees' inboxes.
Monitoring and takedown:
Several companies offer banks and other organizations
likely to suffer from phishing scams round-the-clock
services to monitor, analyze and assist in shutting
down phishing websites.  
Further References
Wikipedia - 
Phishing FAQ - 

DYA (Dynamic Architecture)
What is Dynamic Architecture?
 Three principles namely -
• Architecture facilitates change processes
(Architecture is not a goal in itself, but should
support the objectives of the business) 
• Just-enough and just-intime architecture
(Architecture can be developed incrementally) and  
• Permissible deviations from the architecture
(Non-compliance to the architecture is justifiable in
certain circumstances)
are the basis of the DYA concept, where DYA is an
acronym for DYnamic Architecture.
What is its usefulness?
Developing architecture is a facilitating process
which never stops, and as such is comparable with
strategy and human resource policy. Moreover, it must
not be an autonomous process with a set delivery date,
and we have to forget architecture as a product which
will be complete at a certain moment. Architecture
development must be embedded in the organizational
change processes and the real deliverable of
architecture will then be not the final document, but
the increased adaptability and flexibility of the
organizational change processes. Architecture and
business change processes will have a common goal, and
the benefits of architecture will be greater if the
context, purpose and use of the architecture are made
obvious to everyone from the onset. In a nutshell, no
more architecture for architecture's sake.
It is quite feasible to develop enterprise
architecture incrementally. There is no real necessity
to produce a complete document in one go. Architecture
consists of several levels, consisting of general
principles, more specific rules and guidelines, and
finally detailed models. Architecture can also
influence several domains, for example: processes,
organizational structure, information, applications
and technical infrastructure. Using this multi-tiered
approach, it becomes possible to assign priorities to
the architecture development effort: developing those
aspects which the organization really needs as a first
priority, and the other aspects at a later date or
perhaps developing them in a rough outline.
Architecture development synchronized with
organizational development. This is what we call the
'just-enough, just-in-time' principle, or 'need-driven
architecture development'.
The third principle of DYA architecture is the
understanding that there may be occasions in which
non-compliance to the architecture is justified. The
architect's horizon is not only the needs and wants of
today, but also those of the (near) future. He must
also consider developments elsewhere in the
organization. Sometimes the time available to produce
a result is so short, that all that matters is 'here
and now'. A solution is needed immediately, and the
business accepts that it is a dispensable solution
with a life span of 4 months. These situations have
occurred in the past and will continue to occur in the
future. Diverging from the architecture does not
constitute a mortal sin. Architects should acknowledge
that these deviations can occur and should be able to
provide answers to this type of situation. The answer
can be found in a mechanism to manage and control the
deviations from the architecture and to minimize the
negative consequences. This can be done by defining
two separate development scenarios which can be used
by a project: one within the architectural framework
and one outside the architectural framework. In the
latter case, the project plan should include measures
for migrating to the architectural framework at a
later stage.
The DYA_ concept is built around a model which will
facilitate organisations in designing and improving
their architectural processes. The model contains four
main processes which should be implemented in order to
derive the full benefit of enterprise architecture:
• Strategic Dialogue, in which business objectives are
established and elaborated as business cases; 
• Development with Architecture, in which structural
solutions are implemented; 
• Development without Architecture, in which the
throw-away solutions are implemented; 
• Architectural Services, supporting the other three
processes with principles, guidelines and models.
Using the DYA_ model as a guideline and the DYA_
instruments to assist implementation, organisations
are finally able to make their enterprise architecture
Further References
  (how to make DYA enterprise architecture work?)
 (DYA towards a new perception of architecture)
 (Just Enough, Just Intime architecture)

Semantic Web  
What is Semantic Web? 
The Semantic Web is an evolving extension of the World
Wide Web in which web content can be expressed not
only in natural language, but also in a format that
can be read and used by software agents, thus
permitting them to find, share and integrate
information more easily.
The Semantic Web is a mesh of information linked up in
such a way as to be easily processable by machines, on
a global scale. You can think of it as being an
efficient way of representing data on the World Wide
Web, or as a globally linked database.
The Semantic Web is not about links between web pages.
The Semantic Web describes the relationships between
things (like A is a part of B and Y is a member of  Z)
and the properties of things (like size, weight, age,
and price)
The Semantic Web was thought up by Tim Berners-Lee,
W3C director, inventor of the WWW, URIs, HTTP, and
HTML. It derives from his vision of the Web as a
universal medium for data, information, and knowledge
The Semantic Web is about two things. It is about
common formats for integration and combination of data
drawn from diverse sources, where on the original Web
mainly concentrated on the interchange of documents.
It is also about language for recording how the data
relates to real world objects. That allows a person,
or a machine, to start off in one database, and then
move through an unending set of databases which are
connected not by wires but by being about the same
The main power of Semantic Web languages is that any
one can create one, simply by publishing some RDF that
describes a set of URIs, what they do, and how they
should be used. Because we use URIs for each of the
terms in our languages, we can publish the languages
easily without fear that they might get misinterpreted
or stolen, and with the knowledge that anyone in the
world that has a generic RDF processor can use them.
What is its usefulness? 
If information about music, cars, and tickets (and
everything else) were stored in RDF files, intelligent
web applications could collect information from many
different sources, combine information, and present it
to users in a meaningful way.  
Information like this:
• Car prices from different resellers 
• Information about medicines 
• Plane schedules 
• Spare parts for the industry 
• Information about books (price, pages, editor, year)

• Who is who 
• Dates of events 
• Computer updates 
Further References 
W3C Semantic Web Activity: 
Semantic Web  : 
The Semantic Web: An Introduction : 

What is LAMP? 
LAMP refers to a set of tools (LINUX operating system,
Apache Web server, MySql database and PHP programming
language), that allow for rapid deployment and
development of software applications. LAMP can be
briefly defined as the open source web platform.
Perl/Python are other languages used in place of PHP
and called LAMP system as well.
Linux- Is a free Unix-type operating system. Linux's
functionality, adaptability and robustness, has made
it the main alternative for proprietary UNIX and
Microsoft operating systems. Linux has been adopted
worldwide primarily as a server platform and can run
on most common hardware platforms. The core of the
system is the LINUX kernel which distinguishes itself
from others.
Apache- Apache HTTP Server is aimed at creating a
robust, commercial-grade, featured, and
freely-available source code implementation of an HTTP
(Web) server. Features include compiled modules such
as SSL support (mod_SSL), URL rewriter (mod_rewrite)
etc. With the release of Apache 2.0 apache has become
a robust well documented multi-threaded web server.
MySql - It is multithreaded, multi-user RDBMS. The
combination of MySQL's rock solid stability, high
performance, low overhead and ease of use make it an
ideal choice for online application. MySQL's pluggable
storage engines make it easy to get the fastest
PHP - Known as HyperText Preprocessor, PHP is a
widely-used general-purpose scripting language that is
especially suited for Web development and can be
embedded into HTML. PHP was written as a set of CGI
binaries in the C programming language. It also has
improved support for Object-Oriented programming,
integrated SOAP support, etc. PHP includes a large
number of free and open source libraries with the core
What are its advantages/disadvantages? 
Advantages - 
• With no or less licensing costs and using available
open source libraries brings down the cost of
development considerably. 
• Very tight integration between PHP and Apache, for
instance, eliminates the need for application server
software and in many instances eliminates an entire
physical server tier. 
• Scalability in handling large amount of load and
Flexibility during scale up.
Disadvantages - 
• Non-availability of skilled resources in LAMP. 
• Less support for the application need to depend on
the community or individual developers for solutions
or patches for customization.
Further References 
Wikipedia - 
Apache - 
MySql – 
PHP - 

      Unlimited freedom, unlimited storage. Get it now, on http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/

More information about the AccessIndia mailing list