Dissecting Network Components 476 Dissecting Network Components A laptop that lives all by itself is, at heart, no different than a machine that is connected to a network.. Nearly all c
Trang 1Contents at a Glance
Chapter 1: Networking with Other Machines 475
Dissecting Network Components 476
Hello, Operator? Modem Madness 481
Chapter 2: Managing a Windows Network .491
Speaking of Networking 491
Networking Soft(ware)ly .492
Identifying Computers to Each Other 494
Visiting Windows Vista Network Center 497
Joining a Workgroup 501
Your Laptop’s Name and Address, Mac 502
Playing Nice, Sharing a Folder 506
Accessing Another Computer on a Local Network 510
Mapping a Folder 512
Sharing Devices and Internet Connections 514
Automated Network Diagnostics 519
Chapter 3: Going Wireless 521
Doing What with a Wireless Network? 522
Seeing Hot Spots 524
Working a WiFi Network .527
Does Your Laptop Do WiFi? 531
Disabling the Original WiFi Adapter 532
Building a Wireless Network 533
Setting up a Wireless Network in Windows 541
Cutting the Wires Other Ways 550
Chapter 4: Spinning the Web 555
Cruising the Web 555
Discerning the Good, the Bad, and the Ugly Internet 557
Getting on the Internet 558
Finding Your Way on the Web 561
Taking Internet Explorer 7 Shortcuts 580
Chapter 5: Exchanging E-mail, IMs, and Newsgroups 587
Fielding Microsoft’s Triple Play 588
Using Windows Mail or Outlook Express 592
Feeling Safe with Windows Mail and Windows Live Security 604
Windows Mail and Windows Live Enhancements 609
Minding Your E-mail Manners 618
Snagging Web-based E-mail Programs 620
Letting Your Fingers Do IMing 621
Chapter 6: Communicating with VoIP .625
Rocking the Laptop Telephony 626
Cutting the Cord 627
Getting to VoIP at Home or Work 631
Getting Quality VoIP 633
Equipping a Laptop for VoIP 635
Trang 2Chapter 1: Networking with Other Machines
In This Chapter
Catching up the laptop with the network
Going into the Ethernet
Linking your modem to you
Mainframe and then desktop computers were at first isolated boxes of processors and data Then they became linked to each other through
a local area network (LAN) and to the rest of the world through the Internet.
When the first laptop computers became popular, they followed pretty much the same path At first, the idea was that a laptop was something that could be used between offices I worked with some of the very first portable PCs, lugging them onto commuter trains and airplanes and then using a serial cable to connect to a desktop machine or copying my completed work onto floppy disks to transfer the data
It wasn’t long, though, before desktops and laptops turned to the telephone
to make the connection Specialized mail services like MCI Mail allowed you
to send messages or files to a central computer where they waited for the recipient to sign on and retrieve them over a painfully slow dial-up con-nection where speeds were sometimes measured in minutes per page For years, laptops worked with external dial-up modems the size of a paper-back book; eventually designers found a way to shrink the components of the modem so they could be integrated into the case A little further along
in the development process of the laptop, designers added a network inter-face card (NIC), which brought the Ethernet into the machine.
In this chapter I examine the hardware and software components neces-sary to allow a laptop to join a LAN You stick to wired technology here; in Book VIII, Chapter 3, I discuss the next step in network evolution, wireless communication
Trang 3Dissecting Network Components 476
Dissecting Network Components
A laptop that lives all by itself is, at heart, no different than a machine that is connected to a network Within its case is a microprocessor, memory, stor-age, and input and output components including a keyboard, a pointing device, a display, and connections for use with printers and other external hardware
Now, to become part of a network you must add three more essential elements:
✦ A network interface card (NIC) Greatly simplified in its modern
incar-nation, this is a small set of chips that manages the bundling of packets
of data or commands to be sent out on the network and the reception and unbundling of packets addressed to it from other devices
Nearly all current laptops now come equipped with an Ethernet port that serves this purpose; it accepts a cable with an oversized version of the familiar telephone connector If your laptop does not have an Ethernet port, or if the built-in circuitry is outdated or fails, it can be replaced by a NIC that plugs into a PC Card or ExpressCard slot, or attaches to the laptop through a USB port
✦ A set of wires that links two or more computers and other devices
together In nearly all designs for LANs, the wires don’t go directly from
one computer to another, but instead go through a device located (in
logical terms) as if it were the hub of a wheel This router accepts
incoming data from any device linked to it and then re-routes it to the proper destination — another computer, a printer, a shared modem, or other devices
In a wireless or WiFi system, the laptop broadcasts its signal to a wire-less router that retransmits the information to the proper destination The principles are the same as for a wired system except for the lack
of wires
✦ A software protocol and network management system Today,
network-ing is built into all current versions of the Windows operatnetwork-ing system
Taking a quick trip into the ether(net) The vast majority of LANs are today based around the Ethernet specifica-tion; you’re not required to use it, but you’d have to go well out of your way
to set up a network that employs different conventions (You can also buy a keyboard that doesn’t have QWERTYUIOP as its top row of characters, and you can use Linux instead of Windows.) But for most of us, there is no need
to buck a well-proven trend Ethernet performs pretty well and our goal is get our work accomplished, not to prove a point by being the odd one out
Trang 4Book VIII Chapter 1
The core of Ethernet is a set of definitions of hardware and software proto-cols that encase chunks of data within a packet that includes the sender’s and receiver’s address, as well as other necessary information for communi-cation between machines that aren’t directly connected to each other
Today, laptop users typically use one of three Ethernet flavors which differ principally in their velocity
✦ 1000BASE-T also known as Gigabit Ethernet The current speed champion gives you the basic information you seek right in its name: it’s theoreti-cally capable of moving as much as a gigabit, or 1,000 megabits of data per second
✦ 100BASE-TX Also in common use and runs at speeds as fast as 100 Mbps
✦ 10BASE-T Older systems may offer this, which operates no faster than 10 Mbps
Note that an Ethernet is only capable of working at the speed of the slowest component in a particular connection For example, if you have 1000Base-T NICs but a 100Base-TX router or hub, the network will move data no faster than 100 Mbps If you have a 100Base-TX router that connects to a 10Base-T NIC in a computer on the network, you’re limited to that slower speed
The cable that runs between the Ethernet port on your laptop and a router
or other device is a heavy-duty, higher-capacity version of a telephone wire
As various versions of the standard have been introduced, the cable has gotten a bit more robust; today the best cables are called Category 5e, which
is a slight improvement over (and in most cases interchangeable with) Category 5 At each end of the cable is something called by designers an
8P8C modular connector; the name means “eight position, eight connector.”
(The connector is also commonly but incorrectly referred to as an RJ45 plug;
a distinction without a difference for most users.) Thus far I’ve written only about how an Ethernet is wired Now consider — briefly and simply — how it works
The first thing to understand is that data isn’t sent as a continuous stream from one location to another; if the system worked that way, in one example
it would require opening a channel between my office and Paris anytime I wanted to send an order for fresh brioche Instead, data is cut up into little snippets that are like envelopes with a sender’s address and a recipient’s address on each end
The hardware side of the Ethernet interface inserts each packet into the extremely fast stream of data that moves by on the electronic superhighway;
the computer watches the traffic and looks for a gap large enough to merge into traffic If somehow two or more devices try to fill the same gap, there will
be a collision, but the computer senses this and simply re-sends the data
Trang 5Dissecting Network Components 478
At the router, the electronics in that box scan the intended address for each packet and checks it against a list it maintains for every attached computer
on the network When it finds something intended for one of its clients, it redirects the packet to its destination
Something about spokes Early in this book I explain that a computer accomplishes its magic not because it’s smart, but because it’s extremely fast The same applies to the
physical design (the topology) of a network It doesn’t really matter if the cable
connecting the laptop that sits on the left wing of my desk to the desktop on right side goes 6 feet in a straight line or if it goes down through the floor to a router in the basement and comes up in a hole on the other side of the room and passes through three other machines before arriving at its destination Unless you’re talking about links that travel hundreds of miles, delays caused
by cable length are measured in fractions of thousandths of a second
Most simple networks — including virtually every wired and wireless system
in the home and small office — use a design called hub-and-spoke, also known
as a star topology This sort of network is centered around a hub, switch,
router, or (in a very large or complex system) server The path from one com-puter to another passes through the central device
This sort of design offers advantages:
✦ Some protection The failure of any spoke — whether it’s a NIC in a com-puter, the computer itself, or a networked device such as a printer or broadband modem — doesn’t bring down the entire network
✦ Some workaround And if the hub — a router, switch, or server — fails, the network goes down, the individual computers can continue to do their work albeit without connection to each other
A bit about buses
A less commonly used form of network uses a bus topology: Each machine is connected to a peer machine to its (logically speaking) left or right At each end of the bus, a terminator loops the signal back the other direction.
The bus must remain unbroken from one end to the other (with all the machines turned on and NICs performing properly); the network won’t work if
✦ The cable is damaged
✦ A connector comes undone
✦ A network interface fails
Trang 6Book VIII Chapter 1
Running in rings
A ring topology is a closed system; all the members of a network are arranged
in something approximating a circle and the wiring goes from one machine
to the next, all the way around, until it completes the circuit
All the components — cables, connectors, and interfaces — must be working properly for the network to operate (You may be old enough to remember Christmas tree light sets that were electrified with serial wiring; the failure of one lamp shut down the entire string.)
Hubs, switches, and routers
A hub doesn’t have to sit at the exact center of a circle, like a real hub on a bicycle wheel But it’s situated that way in logical terms
Let me explain that by painting a word picture of my real office:
✦ At the moment, I’m sitting at the keyboard of my main production computer
✦ A short Ethernet cable runs from that computer, along the floor, to an eight-port router on a shelf in the corner
✦ The eighth port on the router goes to a two-foot Ethernet wire that connects to a broadband cable modem that allows every machine in
my network to connect to the Internet at high speed
✦ To my left are two laptops; one connects by a short Ethernet cable to the hub and the other uses its built-in WiFi circuitry to make a wireless connection to the network
✦ Around to my right is another desk with a computer, and that machine plugs into a wall jack that connects about 15 feet down into the base-ment and back up again out through an outlet and from there into the same eight-port hub
Broadening your horizons
What do I mean by broadband? In technical terms it means that the delivery mechanism can bring a wide frequency of signals Wider or broader is better than narrower (like dial-up over an old-style phone system) If it helps you
to visualize, think of broadband as a big, fat pipe full of many different varieties of stuff moving at high speed; that’s got to be better than a thin straw that takes a long time to transport a small amount of just one flavor
Trang 7Dissecting Network Components 480
✦ All the way over on the opposite end of the office is another computer that I use to manage an archive of photos and old files; it connects by cabling that goes down into the basement and over to the hub, traveling about 30 feet
✦ Another cable coming out of the hub connects through the wall to my left
✦ In the room there, the cable goes into a WiFi router that broadcasts a signal throughout my home and office, allowing me to take a laptop out
on the deck on a sunny day or into the family room if I want to play some streaming video or audio there
✦ Finally, the WiFi router has four wired ports of its own, one of which is connected to a cable that stretches about 15 feet to a machine in the study
✦ The eighth port on the router goes to a tw2-foot Ethernet wire that con-nects to a broadband cable modem that allows any and every machine
in my network to connect to the Internet at high speed
In no way does this design resemble a circle And none of the cables are the same length, so the spokes are all irregular But if I wiped clean the image of this complex network and just think in terms of how all the devices (including
a few I left out in an attempt to make this a bit easier to visualize) connect
to each other through the router, what you’ve got here is a hub-and-spoke network
Smarter than a hub
The original design for a hub was for a dumb device that merely brought everything together and then allowed signals to pass back out to every attached device on the network; if the packet wasn’t intended for a particular com-puter, it ignored the information We’ve gone way past that concept by now
Hubs were first replaced by intelligent switches, and now switches have been mostly supplanted
by routers
A switch improved on a hub by adding some intelligence to read the address of an incoming packet and then selecting a path to send it directly to the intended recipient Going directly allows every machine that is part of the network
to use the full bandwidth of the network and also improved its efficiency by reducing the opportunity for collisions between packets
A router, also called a gateway, adds one more very important element to the network switch: the ability to allow an entire network to also share a single broadband modem for Internet access (The delivery system for the modem can be cable, DSL, fiber optics, or a dedicated high-speed telephone connection.)
Another way to look at a router is to think of it
as a device that serves as a LAN hub at the same time it connects to the outside world (or
to another network) through a gateway
Trang 8Book VIII Chapter 1
Hello, Operator? Modem Madness
The purpose of a modem is to translate the digital 0s and 1s that exist within
a laptop into an analog electrical wave that can travel over a telephone wire
The word modem is a concatenation of modulator-demodulator
Today very few of us still use a standard telephone modem, but the same prin-ciple applies to users of much faster DSL and cable modems And the concept
of a modem has been applied to other forms of communications we now com-monly use: wireless networks, cell phones, and fiber-optic networks
Types of modems
In this section I talk about the four most common direct-connection modems:
✦ Dial-up telephone modems
✦ Cable modems
✦ DSL phone line modems
✦ Fiber-optic translators Today, cable and DSL modems are the most commonly used in homes and office Fiber-optic system (including Verizon’s proprietary FIOS service) use
is growing in regions where they’re offered, while old-style dial-up telephone modems are fading away rapidly
Smooth modulater
In most of the modern world, the telephone wires that come into your home and office are little different from the system designed by Bell
in the 1870s They’re a simple pair of copper wires — one (usually covered in green insula-tion) is an electrical common or ground, and the other (usually red) carries 6 to 12 volts of DC power
When you speak into the microphone end of a telephone, your voice modulates the current into a varying wave At the other end of a simple point-to-point circuit, a telephone receives that modulated signal and uses it to make sounds in
a speaker held up to a human ear
The wave is called an analog signal Think of it
as an analogy of the sound: The pitch and volume of the human voice are represented by the peaks and valleys, and the distance between them by an electrical wave
As I discuss in Book VIII, Chapter 6 about Voice over Internet Protocol (VoIP), the basic tele-phone systems become much more complex once they include the ability to call any phone anywhere rather than just connect directly between two points But for your purposes here, imagine all connections are direct
Trang 9Hello, Operator? Modem Madness 482
Dial-up telephone modems The first modem I worked with, in a wire service newsroom, was a box of wires and flashing lights that could move the news to a teletype machine at about 75 bits per second (bps); that’s the rough equivalent of about 8 char-acters per second or 100 words per minute Transmitting just the words (without the photographs, illustrations, and clever cartoons) in the book you’re holding in your hands might take nearly 20 hours
Things were looking a bit more promising when the first telephone modems for personal computer were introduced, quadrupling the speed all the way
up to 300 bps
To send identifiable characters, one behind the other, over a serial communi-cation cable like a telephone wire, the computer has to add coding to mark the beginning and end of 8-bit computer words or bytes It also inserts other data to help with error checking or error correction Therefore, the net throughput of a 300 bps modem might be equivalent to about 27 bytes per second If modems hadn’t advanced beyond that point, the World Wide Web would never have been possible
Now, the big question: Why am I bothering to discuss this ancient and slow technology? Good question; if you have a choice of any of the other, faster means of communication, use them
The first few generations of laptop computers didn’t come with an internal modem There were two good reasons for this:
✦ Not everyone wanted one
✦ The pace of change in modems was so great that it made little sense to put one inside the box It made more sense to ask users to buy the latest portable modem and attach it to a serial port or later to a USB port And then in recent years, modems became so small that they were built into the motherboard of nearly all laptops Many users may not even know they have one inside the box; look for a port on the side of the box for connecting
a telephone cable The connector for a telephone wire looks very similar to the one for an Ethernet cable, except the phone device is smaller
Don’t try to force the wrong connector into the improper port; it’s hard to
do, but some people try See Figure 1-1
The best speed you can realistically expect with a dial-up modem is some-where in the range of about 42K; there are simply too many places some-where a good signal can go bad on the old telephone system
Trang 10Book VIII Chapter 1
The only real advantage to holding on to this old technology is that maybe somewhere, someplace you bring your laptop is beyond the reach of broad-band or wireless communication
But almost everywhere you’ll find a telephone For that reason I maintain an
account with AOL, one of the last of the remaining Internet service providers (ISPs) that maintains dial-up modem service in locations across the United
States and in many nations around the world (AOL also allows for near-instant connection over a broadband link.)
Cable modems From the same people who bring you “The Three Stooges” marathons and reality shows even sillier and less believable than Moe, Larry, and Curly comes the high-speed, generally reliable cable modem link
Cable modems use the same large coaxial wiring that brings television into
your home or office; the cable is broad enough to carry hundreds of video signals as well as Internet It does this by sending multiple signals at different frequencies on the same wire; the Internet is given a chunk of the spectrum for downloading to your computer and uploading from it
In most cable Internet systems, the signals travel as an analog wave The cable modem modulates the digital information in your computer to send it upstream, or demodulates an incoming analog wave to convert it to digital for use in your computer An example of a current cable modem is in Figure 1-2
Cable upsides:
✦ The Internet is constantly available to your computer (as with other broadband technologies such as DSL and fiber-optic systems) You don’t have to dial a number; it’s like electricity in your wall outlet, ready when you need it
✦ You can easily add a router or gateway between the cable modem and your computer to link several laptops or desktops to the same Internet connection (as this chapter explores earlier)
Figure 1-1:
A port for a built-in
dial-up modem
on the side
of a current laptop