Networks and Protocols

Internet Service Provider (ISP) is an organization that provides Internet access services and other Internet-related services.

ISP services may include:
• Internet access via dial-up and cable;
• Wireless Internet access;
• Allocation of the disk space for the storage and maintenance of the websites (hosting);
• Support of mailboxes or virtual mail servers;
• Placement of the customer's equipment on the service provider site;
• Rent of virtual dedicated and virtual private servers (VDS or VPS);
• Data Backup;
• and others.

Internet providers can be divided into several types according to  the services they provide:
• Access providers;
• Hosting providers;
• Backbone  providers;
• Channel providers;
• Last mile providers;
• and others.



In order to ensure compatibility of different networks and their component, Defense Advanced Research Projects Agency (DARPA) invented  a Transmission Control Protocol/Internet Protocol (TCP / IP) during 1970s.

TCP / IP is a set of network protocols according to which computers establish communication with each other. The Internet Protocol Suite is just snippets of code installed on the operating system and open up access to the protocols. TCP / IP is the standard, so the TCP / IP applications on the computer with Windows OS are able to successfully communicate with the same applications installed on the UNIX machine. During the initial period of network development, in 1983, engineers have developed a seven-layer Open Systems Interconnection (OSI) model to describe the process of network communication between the computers. The OSI model consists of physical, data link, network, transport, session, presentation and application levels. Administrators, who constantly work with the Internet and TCP / IP, mainly deal with the network, transport and application layer, but for a successful trouble shooting it is necessary to know the other levels.

Only 13% (570 million addresses) remained
in the global free pool as of 2008.

Internet Protocol Version 6 (IPv6) is a version of the Internet Protocol that was designed to improve Internet Protocol version 4 (IPv4). A number of limitations were removed from version 6, such as the length of the IP-address increased from 32 to 128 bits (i.e., it expanded to 340 trillion addresses), which solves the exhaustion problem of the available address space. In order to improve the performance of routers IPv6 introduces advanced packet headers, enhances protection of information (such as embedded encryption algorithm with a 64-bit key), simplifies the process of device configuration (introduced a feature of autoconfiguration). It became possible to assign priority levels to packets. In addition, IPv6 is upward compatible with IPv4.

Version of IPv6 is designed to develop and expand the Internet in order to ensure openness of information, both for providers and users. It is important to note that the introduction of IPv6 allows not only significantly reduce operating costs, but also expand the range of services.

Due to a rapid development of the Internet technologies, online analogs were provided for many offline services. For instance, regular phones now compete with Voice over IP (VoIP)  telephony. VoIP is a communications system, providing a transmission of the speech signal over the Internet or any other IP-based networks. 


Works Cited: http://www.personal.psu.edu/dvm105/blogs/ipv6/2009/01/  
http://www.youtube.com/watch?v=QDNxVwQwj2U 
http://en.wikipedia.org/wiki/TCP/IP_model 
http://en.wikipedia.org/wiki/Internet_service_provider

Networking

Currently, local area networks (LAN) have a very broad distribution. This is due to several reasons:

- The union of computers in the network allows saving money by reducing maintenance costs of computers

- Local networks provide users with a mailbox in order to send messages to other computers, where documents are delivered from one computer to another in the shortest period of time;

- Local networks with special software organize better sharing of files.

Among other things, in some areas it is simply impossible work without the LAN. These areas are: banking, warehousing operations of large companies, libraries electronic archives, etc. In these cases every single workstation can not store all the information (mainly due to its large volume). Network allows selected (registered on the file server) users to access the information, and network operator grants that access.

There are three main types of computer networks:

- Local Area Network (LAN);

- Wide Area Network (WAN);

- Global Computer Network (Internet).

In addition, each of these networks can be:

- A single server - the network is served by one file server (FS);

- A multi-server - network served by several FS;

- Distributed - Two or more LANs that are connected by internal or external bridge (bridge or interconnection controls process of exchanging data packets between one cable system and another).

Local Area Network - a group of computers that can communicate with each other, share peripheral equipment (e.g., hard drives, printers, etc.) and contact remote central computer or other local networks. LAN can consist of one or more file servers, workstations and peripherals. Users can share the same files, such as data and programs, send messages directly between workstations and protect files with powerful protection tools. The main types of LANs are Ethernet and ARCNET. Moreover, Ethernet can have multiple types of cables:

- Thin Ethernet cable, also known as "Thinnet", has a number of benefits, such as lower cost of the cable and a usage of equipment that is easier to install;

- Thick Ethernet cable, also known as "Thicknet", has received its name due to the use of standard, or a thick Ethernet cable. Thick cable allows connecting greater number of computers in the system and increasing the distance between them. However, this cable is more expensive and its installation is more complicated comparing to a thin Ethernet cable;

- Ethernet over twisted pair. It is cheaper than aforementioned cables and easier to install.

Ways of organizing (topology) of Computer Networks is the physical layout of network components (cables, stations, gateways, splitters, etc.). 

There are three main topologies: star, ring and bus.

In the networks with “Star” topology workstations are connected directly to the file server, but not connected with each other.

In the networks with the "Ring" topology file server and workstations are connected by cable and create a shape of the ring; Packets from one workstation can go through several other workstations before they reach the file server.

In the network with “Bus” topology all workstations and file server are connected to a central cable, called the bus.

Hardware connectivity devices, such as hubs, switches or routers, are the center of data transmission.

The simplest type of such devices is a network hub which works on the physical level of Open Systems Interconnection (OSI) model and simply repeats the data from input port and sends it to output ports.

The next type of devices is network switches which are now widespread. Operating at the data link layer of network protocols, they copy MAC-addresses of connected computers, IDs of the network cards and then forward the packet only to that computer, which MAC-address is written in the packet. Switch can have a dedicated port, so-called UpLink, designed to send packets that haven’t found a recipient in the local area network. 

Let’s take a look at the routers.  They work at the network level of OSI model. A router typically has two IP-addresses – one for the outside world and one for the local network. In a local network router can distribute IP-address via Dynamic Host Configuration Protocol (DHCP) and control valid IP-addresses. Typically, in this case the router is a gateway for computers in a local network. Router’s external address is configured by analogy with a computer, and can be both static and dynamic.

Getting More Out of the Internet

What we most appreciate about the Internet is its vast variety of information. Unfortunately, such a diversity of information makes it difficult to control its accuracy. In order to ensure the relevance and accuracy of the information, many web sites are specially certified.  For example, such organizations as URAC and HONcode provide accreditation of health and medicine related web sites. Web sites that meet standards of aforementioned agencies are entitled to display symbols of URAC and HONcode on their web pages.

Someone may call the Internet a storehouse of knowledge, some an information dump. Huge amount of thematic resources requires certain skills to navigate among them. Skillful application of the latest technological advances allows easing our lives by automating many processes, such as paying bills. Now this procedure is available online for owners of the electronic bank accounts, where paper bills were replaced by e-bills, thus accelerating and facilitating transactions between payers and banks. However, when you share your personal information online, you should always be aware of security issues, despite all advances in data protection, it is still don’t guarantee 100% protection from hacker attacks.



More and more people prefer online education to the traditional one. Remote courses are convenient, as they provide access to the information from any part of the world 24/7. In conjunction with Personal Learning Networks (PLN), online education can become a powerful tool in the hands of students and teachers.
Incomparable advantage of the Internet is the access to numerous websites containing information about various products and services. Now in 10 minutes you can get a complete overview of the latest brand car and its technical parameters, and get a price quote. This allows users to chose an item online and then buy it in the regular store.

Many products can also be ordered in the online stores, which are also referred to as a marketspace. You can find almost anything online, starting with kitchen utensils and finishing with software. Some software is available for free download and is called freeware, other (Shareware) is available for downloading for informational purposes only and requires purchasing after the trial period. Many programs can be found on the torrent web sites (like Pirate Bay) that utilize p2p technology to transfer data, i.e. from one user to another.
Sources: http://www.youtube.com/watch?v=6TLPtSLtM38

Final Project Phase One

Currently I'm enrolled in the Digital Media program, web track. My ultimate career goal is a become a professional web developer and eventually own a business or to be a head of a large company. Profession of web developer embraces vast variety of programming skills. Before starting a career, candidate has to obtain knowledge of programming languages such as PHP, JavaScript, HTML, and CSS; be able to effectively utilize software like web server Apache, MySQL database, Wordpress publishing platform, PHPBB forum, etc. 
The software that I found most convenient to use was Adobe Dreamweaver. It suits both for beginners and professionals, it has a great number of useful tools, such as tags lists, visual elements, text formatting options, that are very handy for web site development . One of the Dreamweaver's features that I use the most is auto completing tag option that provides you all possible suggestions for tag once you started typing it.

Steps I would follow to build my web portfolio:
1. Find free design template online. I chose to use Droopal or Joomla engines as they provide all the necessary tools for a fast and high quality web sites building process 
2. Decide what kind of information I will place on my portfolio. It would contain approximately between 4-7 pages, including my resume and examples of my works, my biographical facts,and links to the resources that I often use. I might also connect my Twitter or Blogger feeds using built-in widgets for aforementioned web site engines. 
3. Create web pages and add a content.
4. Upload on the web-hosting or simply utilize a publishing platform that comes along with blog or web site, such as Wordpress.

Portals

Internet abounds with information of different kind. Therefore, in order to make information access more convenient, some of the web sites combine links for different kind of thematic resources. These web sites are called portals, for instance, Yahoo or MSN.

Such services are convenient to use, as they reduce the time spent for data search. Such web portals attract large flow of visitors which makes them also beneficial for advertisers, placing their advertisements on the portals.
Portals can be divided into several categories:
1. Personal (Horizontal)
2. Vertical
3. Industrial
Personal portals enable users to customize website page according to their certain interests and preferences.
Horizontal portals are designed for a narrower range of consumers, thus they include more detailed information on a chosen subject. For example, USA.gov. or portal dmoz.org contain links for different theme web sites.
Portals that publish information related to a particular area of industry such as health care, automobiles, insurance, or food manufacturing, called industrial portals. For example, such web sites as The Car Portal, Health.org and others
Corporate portals are intended to provide access to corporate information for employers, employees, customers and business partners. Users of Corporate portals are able to share their personal information; employees from different departments can exchange data and collaborate with each other. Great example of such portal is web site of NCCC.

Due to the high rate of information exchange, the Internet has become an indispensable platform for the placement of rapidly changing data such as weather reports, traffic jams or breaking news. For example, Weather.com web site reflects not only the most recent data about weather, but also provides videos of natural disasters, downloadable applications for your computer or smart phone. Also inquisitive users can find tips about their hobbies or travelers info.

Personal Learning Network

With the development of Web technology it has become very convenient to gather links to the useful informational resources into the special Personal Learning Network (PLN) which is advantageous during educational and working process. It helps to connect teachers and students, employers and employees. Creating, searching and sharing of information develop a unique symbiosis between users and expand boundaries of communication.  Currently, the most frequently visited resources that I use are the web sites about programming, business, as well as various online dictionaries and thesaurus.
To build my PLN I chose StumbleUpon , as it not only allows bookmarking web pages, but also supports sharing of this information with other members of the network.
Steps that I've followed to create my PLN:
1. Created a blog to share my own ideas and follow other people posts.
2. Registered an account for StumbleUpon in order to do social bookmarking
3. Signed-up for iGoogle which allows to follow blogs and provides tools for fast access to the different resources like dictionaries, latest news and videos.
4. Registered in LinkedIn (professional network) in order to extend my professional connections and explore current job market requirement.
Though it is important not to "over do" you PLN by registering for too many services which will put you into informational chaos.

Currently my iGoogle page contains links to the latest new about Python and PHP programming languages, daily IT and technology news; information about careers, dictionary search line and To-Do list.  
  


Advantage of PLN is being around large community of users, communicating with people from all over the world whose multicultural experience creates unique environment for learning.

Sinch

Social Networks and Blogs

Social networks are aimed to build an online community consisted of people with similar interests and / or activities. Communication takes place via the internal email service and instant messaging.

Also, there are social networks created to search for objects of one’s interest: web sites, listening to music, reading books and so on.
In the social network you can usually publish information about yourself (date of birth, ducation, hobbies, etc.), based on which other participants can find you. One of the common features of social networks is the "Friends" and "groups".

For advertisers, social networks provide unique opportunities for direct contact with consumers. Every day, millions of users discuss companies, their products and services by sharing their opinions and impressions. As a result, network community can ruin (or vice versa), the reputation of a company with multi-million dollar turnover.

Many people do not realize that information posted on social networks can be found and used by anyone, including those who not necessarily have good intentions. Information about social network users can be found by their employers, parents, children, former or current wives or husbands, debt collectors, criminals, law enforcement and so on.

Blog is a web site, which main contents include regularly added entries that contain text, images or multimedia. Brief entries sorted in reverse chronological order (most recent entry on top) are common for blogs. Blogs are usually public and involve the reader, who may enter into a public debate with the author (in the comments to blog posts or their blogs).

People writing a blog are called bloggers. Combination of all blogs is called a blogosphere.

Blogs main characteristic is the ability of visitor to publish feedback (comments). This feature makes blogs a part of a social network environment that is more advantageous than e-mails, newsgroups, Web forums and chat rooms.



Sources: http://en.wikipedia.org/wiki/Blog
http://www.whatissocialnetworking.com/
http://radio-weblogs.com/0121664/categories/knowledgeManagement/

Spam and Viruses

Since the moment when user registered an email address, he becomes exposed to the risk of viruses or spam.

Worms can be divided into the two classes:

1. Worms, which are run by themselves without your knowledge.
2. Worms, which are activated only when the user opens an attached file.

The first type includes worms, which use errors in mail programs. Such errors are common in the most popular email programs like Outlook Express. For example, many viruses use error IFRAME, which was identified long ago by Microsoft and fixed by installing certain patches. However, worms utilizing this error are the most common.

Worms of the second type rely on the fact that user, for some reason, will open a file attached to the e-mail. In order to encourage the user to run an infected file, creators of worms use different techniques. The most common method is to replace some important documents with an infected file. Almost always worms have "double extensions". In this case, the attached file has a name like: Docl.doc.pif, pict.jpg.com. This principle considers that the e-mail clients do not display the full file name and user will not see the second real extension. When the user thinks that the file is a document or image, the file actually is an executable (with extension exe, com, pif, scr, bat, cmd). When the file is opened, the worm's body is activated.

Complete picture includes other varieties of viruses, such as macro viruses, Trojans and utilities for hidden administration. Although they do not belong to the worms, they can be distributed by the email.

Nowadays email users receive hundreds of spam email on a daily basis. Even though some email servers have inbuilt spam filter, some of the letters are still able to reach users’ mailboxes.

Spam letters usually are easy to determine. Typically, sender’s email address looks odd and suspicious - sd2fdsdf@dfdf.com, ddf243@hfyr.com, gdf2gd56@ggggg.com. But some spammers use "human" addresses. Sometimes it come to the point, where spammers use the address of a person from a famous company - Microsoft, IBM, etc. If you see that the sender email address has similar characteristics, it is better to delete such message immediately.
Subject is also an important criteria. What would you think, if you receive an email with the subject "Re: answer to your question?” And this message comes from the email address which you have never used and have never seen before? This is spam.

The vast majority of spam is used for advertising. Usually spammers advertise product or service, sometimes to increase the number of hits on the web site, more seldom for the viruses or Trojans distribution. But the common goal is to bring their information to the greatest possible number of recipients at a minimal cost. And the sender does not care about the composition of the audience, number is the most important.



Sources: http://en.wikipedia.org/wiki/Spam_%28electronic%29
http://www.online.tusc.k12.al.us/tutorials/viruses/viruses.htm
http://www.youtube.com/watch?v=FXpmgZAjP0o
http://www.cartoonstock.com/directory/c/computer_worms.asp

A Sudden Crossover - Second Life project Final Result

Source: http://www.youtube.com/watch?v=4dB5OgcU0WU