Wap and the Golden Age of Wireless
A golden age of wireless is coming ... really! Despite the proliferation of cell phones and PDAs, very few handheld devices are currently being used to access the Internet and fewer still are used as a conduit to access Information Management Systems.
Today's wireless landscape is still nascent - standards are far from being established and competing systems are in a battle for mind and market share. And the battlefield is littered with the blooded bodies of yesterday's heroes.
I have been designing websites since 1996. In the beginning, it was easy. Someone called me with a project, they sent me the content for their website, which I would then upload to Microsoft Frontpage or a text editor, insert some HTML tags for formatting and some graphics to make the site colorful, and the job was finished.
The wireless revolution changed everything. Almost every electronic device now comes equipped with access to the web and email. Palm tops, laptops, cell phones, even computer screens installed in automobiles are now connected to the internet. The web browsers and operating systems installed on these wireless devices are often very different from what is installed on an ordinary desktop PC.
Many elements of the HTML programming language are not compatible with some of these wireless platforms. As a result, web design has completely changed. Cross-platform programming languages and specifications have been created so that websites can be viewed on any PC or wireless gadget.
Now you have a basic understanding of how and why the program has changed, you are briefly introduced in this article, WAP (wireless application protocol) to be prepared. WAP is an open international standard applications, the use of wireless communications. Its main application is to enable mobile phone or PDA to the Internet.
Before we begin to discuss Wireless Application Protocol, you should first know a little bit about a language called XML. It is a language that enables programmers to define data without telling the web browser how to display it, because XML files are simple text files. As a result, XML data can be displayed on any web browser. This is significant, because as we have already established, wireless web browsers have a hard time with HTML. XML solves this dilemma by putting data in a format that be displayed across all platforms.
WAP browser, the browser running on wireless devices, such as mobile phones. WAP protocol to understand WML (Wireless Markup Language), which is written in XML. In addition to XML, WML using some JavaScript, which is called the reference manual. However, JavaScript coding does not actually directly in WML page, it is to use the script URL, must be compiled into byte code on the server before the JavaScript can be run in the browser's wireless reference.
Wireless markup language uses tags, like HTML. However, the tags are case sensitive. The most important day, which is used, the card tag. WAP pages are known as decks, and they consist of a series of cards that between the opening and closing tags of each card containing sandwich. The maps within the document are then connected.
When a wireless web browser prepares to present the contents of a web page to the user, it downloads all of the cards in the deck at the beginning when the page first loads, and then is able to display the web page and everything in it without making any additional visits to the server.
In the code, there are generally two main types of tasks and requirements to go to. His mission led to switch to a new label within a deck of cards. The task ahead marker has led to action by switching to the previous access card. The other two types of tasks, it is worth mentioning that the refresh task, which will refresh the screen you are using any refresh, if the variable appears on the screen, and air operations missions, desist from any further action being implemented variables.
There are many other nifty tasks and elements that are used in WML such as the timer element. An example of the timer element in action would be to cause a message that is generated by a task in one of the cards to appear on the screen for 3 seconds before disappearing and moving on to the next card in the deck.
If you make a life as a web designer, you must learn in order to create WML pages for WAP-enabled browser. If you're not on a website so that it can be displayed on a wireless computer program, then your customers will be very unhappy. Wireless Internet use is constantly increasing. Not the creation of Web sites that can actually be displayed across all platforms is tantamount to career suicide.
If you are not familiar with Wireless Markup Language, I recommend that you enroll in some courses on a local computer programming institute, or buy some tutorials online. The syntax for the WML language is not too complicated, so if you already have extensive web design experience, learning the language should be relatively easy.
The importance of TCP/IP and its use in the Internet
Many people may not know what TCP/IP is, nor what its effect is on the Internet. The fact is, without TCP/IP there would be no Internet. And it is because of the American military that the Internet exists.
During the days of the cold war, the defense department was interested in developing a means of electronic communication which could survive an attack by being able to re-route itself around any failed section of the network.
They began a research project designed to connect many different networks, and many different types of hardware from various vendors. Thus was the birth of the Internet (sorta). In reality, they were forced to connect different types of hardware from various vendors because the different branches of the military used different hardware. Some used IBM, while others used Unisys or DEC.
TCP (Transmission Control Protocol) and IP (Internet Protocol) were the protocols they developed. The first Internet was a success because it delivered a few basic services that everyone needed: file transfer, electronic mail, and remote login to name a few. A user could also use the “internet” across a very large number of client and server systems.
As with other communications protocols, TCP/IP is composed of layers. Each layer has its own responsibility:
IP is responsible for moving data from computer to computer. IP forwards each packet based on a four-byte destination address (the IP number). IP uses gateways to help move data from point “a” to point “b”. Early gateways were responsible for finding routes for IP to follow.
TCP is responsible for ensuring correct delivery of data from computer to computer. Because data can be lost in the network, TCP adds support to detect errors or lost data and to trigger retransmission until the data is correctly and completely received.
How TCP/IP works
Computers are first connected to their Local Area Network (LAN). TCP/IP shares the LAN with other systems such as file servers, web servers and so on. The hardware connects via a network connection that has its own hard coded unique address – called a MAC (Media Access Control) address. The client is either assigned an address, or requests one from a server. Once the client has an address they can communicate, via IP, to the other clients on the network. As mentioned above, IP is used to send the data, while TCP verifies that it is sent correctly.
When a client wishes to connect to another computer outside the LAN, they generally go through a computer called a Gateway (mentioned above). The gateway’s job is to find and store routes to destinations. It does this through a series of broadcast messages sent to other gateways and servers nearest to it. They in turn could broadcast for a route. This procedure continues until a computer somewhere says “Oh yeah, I know how to get there.” This information is then relayed to the first gateway that now has a route the client can use.
How does the system know the data is correct?
As mentioned above, IP is responsible for getting the data there. TCP then takes over to verify it.
Encoded in the data packets is other data that is used to verify the packet. This data (a checksum, or mathematical representation of the packet) is confirmed by TCP and a confirmation is sent back to the sender.
This process of sending, receiving and acknowledging happens for each individual packet sent over the Internet.
When the data is verified, it is reassembled on the receiving computer. If a package is not verified, the sending computer will re-send it and wait for confirmation. This way both computers – both sending and receiving – know which data is correct and which isn’t.
One nice thing about this protocol is that it doesn’t need to stick to just one route. Generally, when you are sending or receiving data it is taking multiple routes to get to its destination. This ensures data accuracy.
Just the facts:
TCP/IP addresses are based on 4 octets of 8 bits each. Each octet represents a number between 0 and 255. So an IP address looks like:
111.222.333.444.
There are 3 classes of IP addresses:
ranges starting with “1” and ending with “126” (i.e.. 1.1.1.1 to 126.255.255.254) are Class A
ranges starting with “128” and ending with 191 (i.e.. 128.1.1.1 to 191.255.255.254) are Class B
ranges starting with 192 and ending with 254 (i.e.. 192.1.1.1 to 254.255.255.254) are Class C ( You will notice that there are no IP addresses starting with “127”. These are reserved addresses.)
Calculating an IP address
One of the things that always confused me was how to convert IP address to their Binary form. It is quite simple really. IP addresses use the Binary numbers (“1”s and “0”s) and are read from right to left.
Each position in the binary address corresponds to a number, from 1 to 128 and look like this:
128 64 32 16 8 4 2 1
To calculate an address, simply add the numbers where a “1” appears.
For example, the following:
00001010 works out to 10. Like this:
0 0 0 0 1 0 1 0
128 64 32 16 8 4 2 1
You can see that the “1”s line up with the 2 and 8 – when you add 2 plus 8 the answer is 10.
Since an IP address contains 4 of these octets, it can be displayed in binary like:
00001010.00001010.00001010.00001010
Therefore, IP Address 10.129.254.1 would be converted to:
00001010.10000001.11111110.00000001
(8+2) . (128+1) .(128+64+32+8+4+2).(1)
While it’s not important for the average person to know how to figure this stuff out, it is important for someone setting up a small network. That is because TCP/IP also uses what are called subnet masks to determine which addresses are valid. But I won’t get into those for now. And it’s also a neat trick that you can use at parties to show your non-techy friends just how much of a technology geek you are :)
So there you have it – a brief introduction into TCP/IP – the foundation of the Internet.
Posted in: Internet Related| Tags: Internet TCP/IP Importance Network computer number tcp protocol use effect hardware