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Internet
Access
Setting
Keywords in your Website
FTP
Access (used to post files to your website
or transfer files from one PC to another)
Viruses
Spam
Pop-ups
Internet
Access
56K
Modems vs Cable
Modems vs DSL
vs ISDN vs T1
56K
Modems
The old school theory of the limits of a modem speed over
a phone line is that its maximum limit would be 33.6 Kbps.
Even with the introduction of the 56k modem, the theory
is generally still true. A 56k modem avoids the conversion
from digital to analog, allowing it to achieve faster speeds.
Presently, FCC regulations limit the speed to 53k, but manufacturers
are working to waive this rule.
The potential speed of the 56k modem does not mean that
it will transmit at that speed. Many factors can and will
affect the speed that the user achieves. A 56k modem has
the potential download speed of 56 Kbps, but only has potential
for 33.6 Kbps upload speed.
Costs to use a 56K modem would include a phone charge and
the cost of your ISP (Internet Service Provider). The actual
modem can cost $30 - $100, an ISP can cost $15 - $25 a month,
plus your phone charges. Most local phone companies offer
different packages to accommodate your Internet usage.
Cable Modems
The popularity of cable modems is increasing rapidly. Availability
depends on whether the local cable company provides the
service. The increase in popularity has put such great demand
for it, that most cable companies now provide the service.
If they don't, they most likely will in the near future.
With a cable modem, the user can expect anywhere between
500 Ð 1000 Kbps when downloading files from the Internet.
Upload speeds can be anywhere between 128 Ð 500 Kbps. The
cost for the cable modem service is usually $40 - $50 per
month. Some cable providers offer discounts if the user
subscribes for cable TV at the same time.
The signal for the cable modem runs down the same wire as
the cable TV signal. One channel is reserved for the Internet
signal. Additional splitters can cause a reduction in the
signal. The modem works more like a LAN interface than a
modem. Cable modems generally cost between $100 and $300.
DSL (Digital Subscriber Line)
DSL, Digital Subscriber Line, uses the existing copper pair
wiring that exists in most homes. Hardware at both the user
and switch end allows a data transmission over the wires
at a far greater speed than the standard phone wiring. With
DSL, the user has a constant connection, so there is no
need to dial up to the ISP.
Although DSL is not available in all areas, the increase
in popularity is, in effect, causing local telephone companies
to introduce DSL. In general, it is about the same cost
as having a second phone line and paying an additional $19.95/mo
for Internet access. These costs do vary by provider, but
is generally $35 to $50 for approximately 684 Kbps DSL service
and $70 to $90 for approximately 1.5 Mbps DSL service. DSL,
in most cases, does not require an additional phone lineÑthe
DSL service attaches to your existing phone line. The DSL
router or modem connects the DSL line to a local area network
or an individual computer.
DSL providers offer a choice of speeds ranging from 32 Kbps
to 1.54 Mbps. However, the distance between the customer
site and the central office determines the maximum DSL speed
for a site. To put it in perspective, a 2.5MB file would
take 12 minutes to download with a 28.8 modem, 2.5 minutes
with a 128 kbps ISDN line and 52 seconds with a 384 Kbps
DSL. A 25MB file would take 120 minutes to download with
a 28.8 modem, 26 minutes with a 128 Kbps ISDN line and 8.5
minutes with a 384 Kbps DSL.
ISDN (Integrated Services Digital Network)
ISDN is a system of digital phone connection that allows
data to be transmitted simultaneously across the world using
end to end digital connectivity. Bearer channels (B channels)
occupying a bandwidth of 64 Kbps carry voice and data. Some
switches can limit B channels to 56 Kbps. A data channel
(D channel) can handle signals of 16 Kbps or 64 Kbps, depending
on the service provider.
The two basic types of ISDN services are Basic Rate Interface
(BRI) and Primary Rate Interface (PRI). BRI has two 64 Kbps
B channels and one 16 Kbps D channel for a total of 144
Kbps. This service is geared towards the needs of most individual
users. PRI has larger capacity requirements. Typically the
channel structure is 23 B channels plus one 64 Kbps D channel
for a total of 1536 Kbps. To access BRI service, it is necessary
to subscribe to an ISDN phone line. The user must be within
18,000 feet of the telephone company central office.
To use ISDN services, the user will need to purchase two
main devices: ISDN Terminal Adapters and ISDN Routers. The
cost varies among providers, but prices could be expected
between $35 and $40, with an additional fee for each connection
made.
T1
T1 is a digital carrier facility used to transmit DS-1 formatted
digital signals at 1.544 Mbps. It is made up of 24 digital
channels, which requires a digital connection device, CSU/DSU,
to connect to four wires to carry the information. Most
ISP's have a T1 or a fractional T1 line as their connection
to the Internet. A full T1 should accommodate from 1 to
200 users and other services from an Internet connection.
Most PC modems are analog, for T1 the user will need digital.
Digital technology for 56K modems has become popular and
is now affordable for the user. T1 is the major carrier
of Internet traffic. The T1 connects the backbone provider
to the ISP provider via the telco (telecommunications Provider).
The signal comes into the CSU/DSU and then goes to the router.
From there it goes into the master name server and may be
routed to other servers. One of the servers may be a modem
or terminal server that allows the user to connect to the
Internet. The user logs on to this local network and the
proceeds to the larger network, the Internet.
CSU/DSU is an acronym for Customer Switching Unit/Digital
Switching Unit. It is a piece of equipment that connects
a leased line from the telephone company to the customer's
equipment, such as a router. It performs line encoding and
conditioning functions. In general, they act as an interface
between 56K, T1 or T3. Two additional hardware components
are necessary to use T1 technology. First a router with
a built in T1 link. Second a NIC, Network Interface Card.
With a T1, there can be as many IP addresses that are needed
or according to the ISP IP address policy. With a T1, you
can run your own DNS, mail or web servers. Billing depends
on the ISP. Some will bill all-inclusive while others bill
for access and the telco bills separately.
Some types of 2-way video conferencing and other sustainable
high bandwidth transfers do not work well on T1 because
the flow of data from these applications are packet based.
Setting
Keywords in your Web site
Setting Keywords properties
Many search-engine robots (programs that automatically browse
the web gathering information for search engines to index)
read the contents of the Keywords meta tag and use the information
to index your pages in their databases. Because some search
engines limit the number of keywords or characters they
index, or ignore all keywords if you go beyond the limit,
it’s a good idea to use just a few well-chosen keywords.
Enter your keywords, separated by commas, in the text box
labeled Keywords.
Setting Description properties
Many search-engine robots (programs that automatically browse
the web gathering information for search engines to index)
read the contents of the Description meta tag. Some use
the information to index your pages in their databases,
and some also display the information on the search results
page (instead of displaying the first few lines of your
document). Some search engines limit the number of characters
they index, so it’s a good idea to limit your description
to a few words (for example, Pork barbecue catering in Albany,
Georgia, or web design at reasonable rates for clients worldwide).
Enter descriptive text in the text box labeled Description.
Setting Refresh properties
Use the Refresh element to specify that the browser should
automatically refresh your page—by reloading the current
page or going to a different one—after a certain amount
of time. This element is often used to redirect users from
one URL to another, often after displaying a text message
that the URL has changed.
Delay is the time in seconds to wait before the browser
refreshes the page. To make the browser refresh the page
immediately after it finishes loading, enter 0 in this text
box.
Action specifies whether the browser should go to a different
URL or refresh the current page, after the specified delay.
To make a different URL open (rather than refreshing the
current page), click the Browse button, then browse to and
select the page to load.
Setting Base properties
Use the Base element to set the base URL that all document-relative
paths in the page are considered relative to.
Href is the base URL. Click the Browse button to browse
to and select a file, or type a path in the text box.
Target specifies the frame or window in which all linked
documents should open. Choose one of the frames in the current
frameset, or one of the following reserved names:
• _blank loads the linked document in a new, unnamed
browser window.
• _parent loads the linked document into the parent
frameset or window of the frame that contains the link.
If the frame containing the link is not nested, then this
is equivalent to _top; the linked document loads into the
full browser window.
• _self loads the linked document in the same frame
or window as the link. This target is the default, so you
usually don’t have to specify it.
• _top loads the linked document in the full browser
window, thereby removing all frames.
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