These IP addresses are divided into classes. The most common of these are classes A, B, and C. Classes D and E exist, but are not generally used by end users. Each of the address classes has a different default subnet mask. You can identify the class of an IP address by looking at its first octet. In some scenarios, the default subnet mask values do not fit the needs of the organization, because of the physical topology of the network, or because the numbers of networks or hosts do not fit within the default subnet mask restrictions.
The next section explains how networks can be divided using subnet masks. This network is 8-bit network prefix. Its highest bit is set to 0, and contains a 7-bit network number and a bit host number. A maximum of , which is 2 7 -2, networks can be defined ; two is subtracted because all an 0 and 1 subnet cannot be used in certain routers using RIP-1 Protocol.
Each network supports a maximum of 16,, 2 24 -2 hosts per network. The class A network address block contains 2 31 power 2,,, individual addresses. The station provides easy access to the venture capitalists and established companies at the other end of the Caltrain line in Silicon Valley. For the first decade of the 21st century, the internet was dominated by Microsoft Internet Explorer.
In , the software was the most popular way to browse the web in most countries, with Firefox popular in some parts of Eastern Europe and Asia. Since then Google's Chrome browser, which first released in , has exploded in popularity. It is now the most popular browser in almost every developed country. On the other hand, in much of sub-Saharan Africa, the most popular browser is Opera.
This is probably because many people in these countries access the internet using their cell phones, and Opera offers a mobile browser that works well on low-end smartphones. Right now, three companies dominate the global market for mobile phones, and they've largely divided the market by income. In wealthy countries, Apple's iPhone is popular. In poor countries, especially in sub-Saharan Africa, Nokia often dominates.
These data are based on web browsing patterns, so it may not be a perfect reflection of the number of units sold by these companies. In , Facebook was already one of the most popular social networks in the world, but over the last five years it has become totally dominant. For example, in Brazil was dominated by Orkut, a social network created by Google in But Facebook surpassed Orkut in Brazil in One factor in Facebook's growing global popularlity is Facebook Zero.
Under this program, Facebook pays the data charges for users who log into a stripped down version of Facebook from their mobile phones. The program has made Facebook accessible to millions of users who wouldn't otherwise be able to afford it.
If you've entrusted your data to Google, Facebook, Yahoo, or Microsoft, there's a good chance it's stored at a location marked by one of these pins. Smaller web companies store their servers in data centers managed by third parties, but the internet's largest companies have their own dedicated data centers with hundreds of thousands of servers in them.
These data centers are located around the world. That has two advantages. First, locating data centers close to users allows data to be delivered more quickly. Second, it helps provide redundancy: if user data is kept in multiple locaitons, it will be safe even in the event of a catastrophic failure at one data center.
On this map, Google data centers are red, Microsoft data centers are yellow, Yahoo data centers are purple, and Facebook data centers are blue.
This is not an exhaustive list of these companies' facilities. All of these companies are secretive about their operational details, and so some of the companies' data center locations haven't been publicly disclosed. The biggest internet companies have data centers around the world, but a disproportionate share of their data centers are located in the United States.
And American data centers are clustered in a few states, notably Oregon, Iowa, and the Carolinas. These states have several important advantages. One is cheap power. For example, Oregon has cheap hydroelectric power that has attracted several companies to Oregon. Iowa and North Carolina also offer affordable electricity.
This map shows what percentage of American homes had broadband internet access in Broadband penetration in the US is heavily linked to geography. The West, Northeast, and upper midwest have the highest broadband adoption, while high-speed internet access is less common in the south. One reason for the low levels of broadband subscription in some parts of the United States is availability.
At the end of , there were still significant parts of the country where fixed broadband service wasn't offered. Satellite internet service is available almost everyone in the United States, but it tends to be a lot more expensive than fixed broadband connections. And the long delays in satellite communications make it unsuitable for interactive applications such as video games and voice calls. Note that the data on this map should be taken with a grain of salt.
It's the best data we have available, but it's based on self-reported data from ISPs that isn't always accurate. Together, those four companies account for more than two thirds of all residential internet subscriptions in the United States.
Cable companies account for almost 60 percent of subscriptions, with telephone companies accounting for most of the remainder. These statistics actually overstate the amount of broadband competition in the United States, because although there are about a dozen ISPs with at least a million subscribers, most households don't have more than two options for high-speed residential internet access: a local cable monopoly and a local phone monopoly.
Cable companies generally don't try to enter areas already served by other cable companies, nor do telephone companies try to poach customers from other telephone providers.
For the most part, the broadband market is dominated by the same phone and cable companies that have dominated telecommunications for decades. But one big addition to the broadband market is Google, which launched a fiber optic network in Kansas City in And Google is considering expanding into about 10 other metro areas in the American south and west. Institute for Local Self-Reliance.
Frustrated with poor service offered by incumbent broadband providers, about municipalities across the country have built their own government-owned broadband networks. While might seem like a big number, most of these towns are quite small.
The largest, Chattanooga, TN, only has about , residents, and some have as few as So those towns account for a tiny fraction of the US population. Some of these networks are extremely fast. Click for an interactive version of the map. Incumbent broadband providers have reacted to the municipal broadband trend by arguing that it's not fair for governments to compete with the private sector.
In 19 states, state legislatures have responded with legislation restricting municipalities from building their own broadband networks. That has taken some of the wind out of the sails of the municipal broadband movement, but new municipal networks keep popping up in states where the law allows them. Social media sites like Twitter enable a lot of public discussion of the important issues of the day. But they also enable an even larger quantity of frivolous conversation. Last September was a good example.
The nation was discussing two big topics: possible US involvement in a the war in Syria and Miley Cyrus's scandalous dance moves. But twerking was a more popular subject in most other states. One of the amazing things about the internet is the way it permits the collection and aggregation of large-scale data about human behavior. For example, this map shows where people are tweeting about sunrises over the course of a hour period.
There's a yellow flash of sunrise tweets whenever the sun rises above the horizon in a part of the world. You can see an interactive version of this map here. Viewing pornography is one of the most popular uses of the internet. This map shows data from the popular porn site Pornhub. The data suggest that liberal states such as Illinois and Massachusetts are the heaviest pornography consumers, while conservative states such as Idaho and South Dakota consume the least pornography. The average Massachusetts resident is responsible for almost twice as many pageviews per capita as the average Idaho resident.
I've omitted Kansas due to a methodological problem with Pornhub's data. Wikipedia is a global online encyclopedia that anyone can edit, and it has editions in more than languages. Many articles are "geotagged" with a physical location. Researchers at the Oxford Internet Institute plotted these points on a map, providing a beautiful map of the locations that are subjects of Wikipedia articles. Unsurprisingly, Wikipedia contributors writing in different languages focus on different parts of the world.
Most of the yellow dots from the Persian edition of Wikipedia are in or near Iran. French Wikipedia has more information about continental Europe while English Wikipedia dominates English-speaking countries. The density of information reflected by this map is amazing. Wikipedia has articles about almost every part of the Earth that's inhabited by human beings, and this map would likely be even denser if it included other major languages such as Spanish, Russian, and Chinese.
Here's another map showing which languages people around the world use online. Each dot on the map represents a cluster of tweets, and the color represents the language spoken in those tweets. English is ubiquitous online, so Fischer chose a neutral grey color for it so it wouldn't overpower the other colors.
A point-to-multipoint LAN architecture, POLAN uses optical splitters to split an optical signal from one strand of singlemode optical fiber into multiple signals to serve users and devices. These types of networks are built and owned by businesses that want to securely connect its various locations to share computer resources.
Through a virtual point-to-point connection, users can access a private network remotely. Smart Building. Related Tags. Emerging Technology. Convert to PDF. About the Author.
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