Before you add cable Internet service to your home or office, make sure you’re getting a high-quality cable television signal.. Insist that the cable television connection be brought up
Trang 1✦ You can also add a WiFi wireless router to spread a signal throughout your home or office, allowing you to bring your laptop from room to room
Courtesy of Linksys
Even though a router subdivides access to a single connection, the chances are you may never notice an impact The incoming signal is very fast, and the chances that any two machines will make a major demand on the system
at the exact millisecond is very unlikely
Before you add cable Internet service to your home or office, make sure you’re getting a high-quality cable television signal You’re going to be using the same incoming cable you already use; if it’s less than acceptable for Moe, Larry, and Curly, it’s not going to be very good for YouTube Insist that the cable television connection be brought up to specifications; the company may have to add an amplifier at the street or in your home to improve a weak signal
The downside of cable modems
Most cable Internet offerings are unbalanced, meaning that the download
stream of web pages, audio, video, and e-mail is given a bigger piece of the
“pipe” than the upstream signal (which might include a request for a web-site, an order for a pizza, or a transfer of funds in your banking account)
Figure 1-2:
The Linksys CM100 modem works with most cable systems and links to a router or computer by Ethernet or USB cable
Trang 2Book VIII Chapter 1
This generally makes sense, although if you intend to send large amounts of graphics or video, you may want to look for a broadband service that gives you more speed for uploading For most users, much more data comes downstream to your laptop than goes upstream
Here in my office, I use a cable modem for the Internet I typically receive a download signal that ranges from about 5 to 7 Mbps (more than 100 times faster than a dial-up modem) and an upload speed that ranges between about 280KB and 1.8 Mbps Why do I report a range of speeds for download-ing and uploaddownload-ing? Because the speed of travel is affected by the traffic on the road, or in this case, the traffic in the pipe
The cable between your home or office and the central office of the cable company is shared by all users along the way; it doesn’t matter what televi-sions shows they’re watching, but if you happen to share a cable with one or more neighbors who are heavy downloaders of Internet graphics, it could slow down response The same applies when it comes to uploading; if some-one on your cable is running a 24-hour webcam pointed at his goldfish bowl,
it just might slow down your ability to upload your own files
In truth, though, cable companies generally do a pretty good job of balanc-ing out the loads They may add extra cables in areas with lots of customers
or otherwise adjust their service, such as replacing older copper-based coaxial cables with fiber-optic links
Consider carefully whether you want to give over your Internet connection
to the cable company if
✦ Your cable television system is prone to regular outages
✦ You’ve had other problems with them
The only way to find out the quality of service you’ll receive may be to try it out; if you find that the useable speed is too slow for your needs, ask the cable company to make it better or consider changing to a different provider
What’s up, DOCSIS?
When cable Internet service was introduced, a number of technical designs
(protocols) were put forth for the modem’s design Today, though, nearly all devices adhere to a standard called DOCSIS (Data Over Cable Service Interface Specification).
Your modem must meet the requirements of your particular cable company;
once you’re connected to the Internet it doesn’t matter what type of modem
is used by the person or web site at the other end
Trang 3You can get a cable modem a number of ways:
✦ Some cable companies provide a free modem with their service
✦ Some cable companies require you to purchase or rent one
✦ You can buy your own cable modem, although the cable company might not provide support for something they didn’t install
DSL modems Sometimes speed limits are made to be broken, and that’s what technology allowed designers to do in the 1990s: They found a way to push past what had been considered the physical limits of the original telephone system
Digital Subscriber Line (DSL) service manages to deliver Internet downloads
at speeds of as much as 1.5 mps, about 30 to 40 times as fast as a standard dial-up telephone modem could deliver DSL takes advantage of the fact that standard voice telephone service uses only a small segment of the available frequency range of copper wiring, sending analog voice signals in the range from 0 KHz to 4 KHz; that narrow band works well over long distances The now mostly outmoded dial-up modem modulates its signal into the same 4 KHz-wide band; generally you can’t use the same standard telephone line for both voice and data at the same time The engineers who developed DSL set their sights higher: A DSL modem sends its signals in the frequency range between 25 KHz and 1 MHz, much higher and wider on the wire And they left in place the 0 to 4 Hz channel, meaning that users can retain their voice telephone service on the same phone line if they choose
DSL upsides:
✦ DSL is much faster than dial-up
✦ The DSL line from your home or office to the phone company’s switch-ing center isn’t shared with other users You don’t have to worry about how much the bandwidth your neighbor is grabbing
DSL downsides:
✦ It can only deliver a fraction of the speed brought by cable or fiber-optic systems
✦ DSL is only available where the plain old telephone system isn’t very, very old and decrepit and places that aren’t too far from the phone com-pany’s central office Generally, the service is available to homes or offices no farther than 2 or perhaps 3 miles from a central switch where the signal can be moved onto newer, higher-capacity technology
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At first, DSL was offered only as an upgrade to existing voice telephone customers But today, as more and more people use cell phones or VoIP
technologies, the phone companies have begun to offer naked or dry-loop
DSL service That may sound either enticing or uncomfortable, but all that means is that the system only delivers the high-frequency bandwidth between 25 KHz and 1 MHz and not offer a voice-service dial tone lower on the radio-frequency spectrum
As I warn about cable modem providers, make sure you receive a good, qual-ity voice telephone service before committing to using DSL; if they can’t give you a signal clear enough to speak with your friends and family, how can they bring an Internet channel good enough to surf the Web?
Fiber-optic systems
A developing wave in technology, led in the United States by Verizon Communications, is fiber-optic service Verizon cleverly calls its offering FiOS, which stands for fiber-optic service Another name for this type of
service is Fiber to the Premises (FTTP).
Fiber optics to the home is a 21st-century design Today, its slowest offering starts about where cable Internet begins, at 5 Mbps downloading and goes
on from there to speeds of as much as 30 and even 50 Mbps
Fiber-optic upsides:
✦ The biggest advantage is that it’s the newest technology available to consumers The telephone system dates back to about 1875, cable tele-vision was introduced in the 1950s, and DSL is a retrofit to Alexander Graham Bell’s original concept
✦ Uploading is much faster, starting at about 2 Mbps and currently topping out at about 20 Mbps
✦ Fiber-optic service providers offer various levels of service; obviously the faster the speed, the higher the price
As with other types of Internet service, your results may vary because of the condition of wiring at your home or office, the quality of the cable in your neighborhood, and Internet and network congestion Fiber-optic service and other types of Internet carriers (including cable, DSL, and dial-up telephone) have two significant differences:
✦ Fiber-optic cables carry signals in the form of laser-generated pulses
✦ The signal is digital from your computer to the fiber-optic system
Trang 5Instead of a modem, a fiber-optic system uses a device, called an Optical Network Terminal (ONT), that converts incoming pulses of light to an
electri-cal signal that travels over an Ethernet cable to your computer; going the other direction, the ONT converts an Ethernet signal back to pulses of light Because fiber optics is the new kid on your block, it holds the promise of many future enhancements You can expect services like
✦ Virtually unlimited movies on demand
✦ Video conferencing
✦ Burglar alarm monitoring
✦ Automated meter reading Testing your speed You know what the seller has promised you But how fast is your Internet connection really performing?
✦ Check with your ISP for any utilities or notices of problems (or upgrades);
go to the Web page for your provider and look for a support page
✦ Test your Internet connection Many independent and free services report on your upload and download speeds as well as any quality issues it can detect Some services allow you to check your results against those reported by neighbors using the same company for Internet, or to see how your results stack up against those who use a competitor’s service
I make it a habit to check in on the system’s quality of service every few weeks to see if there’s been any significant change in one way or another; I also go to one or the other web site (in the following list) anytime I suspect there may be a problem with my service
I regularly use these two very reliable test pages:
✦ www.speakeasy.net/speedtest A site run by a company that resells
Internet services to small businesses Their site offers the ability to com-municate with servers spread around the United States; I usually test a nearby site and a distant one An example of a test is shown in Figure 1-3
✦ http://miranda.ctd.anl.gov:7123 A test site at the Argonne National Laboratory in Argonne, Illinois You receive an upload and download speed report, as well as details that may help you, or a technician, trou-bleshoot a slowdown in your Internet service
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Figure 1-3:
A Speak-easy speed test of a broadband Internet connection, showing a healthy download speed of 7,165 kbps (7.2 Mbps) and an upload speed of 1,845 kbps
Trang 8Chapter 2: Managing a Windows Network
In This Chapter
The software side of networking
Clicking, pointing, and configuring your way to connectivity
Naming machines and workgroups
Sharing folders, files, and printers
Sharing an Internet connection
So you have this wonderfully equipped, extremely capable portable com-puter that allows you to do all of your computing tasks — from business
to entertainment — anywhere in the world Why would we possibly want to hook it up to other computers in a local network or over the Internet? It’s not a trick question For many of us, our laptop is the be-all and end-all
up to a point The fact is that, like humans, eventually even a computer needs
to have a bit of discourse and interchange with others
What’s the latest news? Who has sent us mail? What is the balance in our checking account? Has the home office changed the prices on Model 6SJ7 widgets, and how many are in stock in the warehouse? The answers to each
of these questions lie somewhere else: on another computer that may be across the room, across the country, or somewhere in that cloud of informa-tion we call the Internet
And there are other reasons Can I get a printout of my order? Can I synchro-nize my calendar with the other members of my workgroup? Can I back up
my irreplaceable files on a remote server?
Speaking of Networking
In the early days of computing, setting up a network was a black art requir-ing squads of specialists, companies of electricians, and platoons of
techni-cians to oversee the installation of cabling, network interface cards (NIC),
and modifications to operating systems that were not intended to play well with others
Trang 9We’re past all that: Today all current versions of Windows come equipped with fully capable networking software and nearly every laptop is good to
go with a built-in NIC for wired networking and a WiFi module for high-speed wireless communication
A few definitions are in order:
✦ A NIC is an adapter that controls the flow of information to and from a
laptop when the machine is connected using an Ethernet cable It’s
called a card because in its original form it was an adapter that plugged
into the bus of a desktop PC Today, network interface circuitry is built into nearly all computer motherboards
✦ Networking protocols are collections of software that work with the
oper-ating system to manage the incoming and outgoing flow of data
✦ A WiFi adapter is a transmitter/receiver for wireless communication
between a laptop or desktop and a base station or other device
The NIC has a connector, which looks like a slightly oversized telephone jack, that attaches to an Ethernet cable; today’s most commonly used cables are
called Category 5 or Category 5e; they differ slightly in the stringency of their specifications That’s a fancy way of saying that 5e (as in enhanced) is
theoret-ically capable of delivering a higher quality of communication Both 5 and 5e work with networks that deliver data at speeds of as much as 100 Mbps
If you’re buying new cable, use 5e And if you’re taking the next step up, to Gigabit Ethernet, use Category 6 cabling, designed specifically for that speed Whatever cable you use, one end attaches to the NIC and the other to a router, switch, hub, or (in some arrangements) directly to another laptop or PC
If your laptop doesn’t have a NIC or WiFi module, or if you need to work around an outdated or failed piece of hardware, you can install hardware for one or both functions in a PC Card or ExpressCard slot, or as an external device that attaches to a USB port You need a port that delivers USB 2.0 speed for Gigabit Ethernet; the older USB 1.1 specification supports 10 or
100 Mbps Ethernet communications
Networking Soft(ware)ly
On the software side, you need a driver to connect your NIC to the operating system, and your operating system needs to supply network protocols that are compatible with the network to which you seek a connection Windows can support multiple protocols on the same system
To see the networking connection properties of your machine, do the following:
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Under Windows Vista, do this:
See Figure 2-1 for an example of a Vista report
For Windows XP users, follow here:
The Local Area Connection Status screen appears
A list of protocols in use appears
Current operating systems typically include some or all of these built-in net-work protocols:
✦ Client for Microsoft Networks This is the essential piece of software for
standard Windows-based networks; it is needed in order to be able to remotely access folders, files, printers, and other shared resources It is only required in Microsoft-to-Microsoft networks; if your office or organi-zation uses a different protocol it is necessary only if you travel with your laptop to a location set up differently
Figure 2-1:
This Vista report shows the networking components
in use by the NIC, in this case a
built-in Realtek chipset