Mac OS X Leopard - ARCAism

Technology Description
CHAPTER 9 CONNECTING TO THE INTERNET 163
Satellite Satellite broadband provides high-speed access utilizing satellites to provide the
communication over great distances. Satellite broadband is generally slightly more
expensive and slightly slower than other methods of broadband; it is a viable
alternative especially in rural areas where other technologies are unavailable or
prohibitively expensive. The big disadvantage of satellite broadband is a latency
problem where a delay of 500 to 900 milliseconds is added to any other network
latency transmitting the signal into space and then back again. Although this is not a
big deal for casual Internet usage including web browsing and e-mail, it’s a burden for
real-time Internet activities such as VoIP (and it’s a real killer for online gaming).
Besides the technologies listed in Table 9-1, a range of other technologies is available, and
new ideas and technologies are constantly being developed. What’s interesting about almost all
of these, though, is the following:
• They all carry IP packets from point A to point B.
• In a broadband environment, most of these technologies (except in most cases wireless
technologies) usually just bridge a gap between the Internet and a router on your end.
Because of this, the actual broadband technology has little to do with how you set up your
computer to take advantage of it. When the broadband connection enters your home, office, or
company, it is usually run into an Ethernet or Wi-Fi router, which in turn you connect to with
your computer using standard TCP/IP networking.
TCP/IP Networking
TCP/IP networking consists of a collection of networking protocols collectively known as the Internet Protocol
(IP) suite. In very general terms, Transmission Control Protocol (TCP) is responsible for application
data carried over the Internet, and Internet Protocol (IP) is responsible for communication data. So
although TCP carries the message, IP makes sure the message gets where it needs to go. When you configure
your networking, you are essentially setting up your computer as a uniquely identifiable destination
on the Internet for IP to successfully deliver TCP data to your computer.
The current IP protocol being used today is version 4. IPv4, in theory, addresses each computer on
the Internet with a unique address made up of four series of numbers, called octets, that range from
0–255. A typical IP address may look like 153.29.250.112.
For those of you keeping count, this means IPv4 can address, in theory, only a bit more than 4 billion
devices. When this was conceived in the early 1980s, a device was a computer, and 4 billion seemed like
a lot. Today not only are there a lot more computers, but there are other devices such as phones,
watches, automobiles, and more, that use TCP/IP. In addition, a significant chunk of those 4 billion
address are reserved for special uses, and you may notice a problem . . . we are running out of IPv4
addresses.
According to IANA (the organization responsible for assigning IP addresses), the current projected
date when all IPv4 addresses run will be around 2011 or 2012. This won’t matter much if you go by the
Mayan calendar, which says the world will end then anyway, but for the rest of us, it’s a problem. Although
there are a number of ways to extend IPv4 (IP Masquerading, NAT, and other technologies that are common
today), a new version of IP, IPv6, has been defined and is currently being deployed. (The U.S.
government is pushing for deployment for all civilian and defense vendors by the summer of 2008.) For
comparison, IPv6 supports approximately 3.4✕10^38 addresses.