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DSL |
(Digital Subscriber Line) –
DSL is the optimal connection for today's small-to-medium
business because of its speed and flexibility. DSL is a
high-speed transmission technology using existing copper
wiring; this allows high-speed data communication. It is
popular because the copper wire eliminates the cost of a
local loop for connection. xDSL refers to different
variations of DSL, such as IDSL, ADSL, HDSL, and RADSL. |
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ATM |
Asynchronous Transfer Mode. A high-speed
network protocol especially good for real time voice and
video. DSL lines normally use ATM as the underlying
data-transport protocol beneath TCP/IP. |
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CLEC |
Competitive Local Exchange Carrier. |
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Central Office |
A circuit switch that terminates all the
local access lines in a particular geographic serving area;
a physical building where the local switching equipment is
found. DSL lines running from a subscriber's home connect at
their serving Central Office (CO). |
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CPE |
Customer Premise (or Provided) Equipment. A wide range of
customer-premises terminates equipment, which is connected
to the local telecommunications network. |
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CSU |
Channel Service Unit. |
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DHCP |
(Dynamic Host Configuration Protocol) - A TCP/IP protocol
that allocates IP addresses automatically to any DHCP client
(any device attached to your network such as your PC) so
that addresses can be reused when the client no longer needs
them. |
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Digital Loop
Carrier |
DLC. Equipment used to concentrate many local
loop pairs onto a few high-speed digital pairs or one fiber
optic pair for transport back to the Central Office (CO). |
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DSLAM |
(Digital Subscriber Line Access Multiplexer) – The network
device placed at a telephone company CO, that accepts all
the DSL lines from multiple customer DSL connections and
puts the signals on a high-speed backbone line, with some
combination of ATM, frame relay, or IP networks. DSLAM
enables a phone company to offer business or home users the
fastest phone line technology (DSL) with the fastest
backbone network technology (ATM). |
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Ethernet
|
A
LAN used to connect devices within a single building or
campus at speeds up to 10 Mbps. Ethernet is defined at layer
one (physical) and layer two (data link). Based on Carrier
Sense Multiple Access/Collision Detection (CSMA/CD),
Ethernet works by simply checking the wire before sending
data. |
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Firewall |
This is a combination of software and
hardware that filters or blocks traffic from a public
network. A firewall renders parts of the private network
inaccessible and invisible to the public network. It
prevents unauthorized and/or unrecognized access.
|
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Hub |
A
hub connects devices together. The key characteristic of
hubs is whether or not they are switched, and whether they
support 100mbps or not. For home use, unless you are doing
some really strange stuff, the cheapest hub from a name
brand is adequate. For DSL, one port will be used by the DSL
modem, leaving the rest free for your computers. |
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IDSL |
IDSL is DSL at 144 KBPS uses ISDN
transmission. IDSL does not use any kind of dial up nor
involve per-call fees. For those that live too far. IDSL is
the only DSL option. IDSL tends to be priced at a rather
higher rate per bit of speed, than any regular DSL. IDSL can
still be a very satisfactory solution for data transmission
compared to the alternatives (modem). |
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ILEC |
Incumbent Local Exchange Carrier, i.e., a regional Bell
operating companies, i.e., the phone companies. |
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Inside wiring |
All phone service wiring between the Point of
Demarcation up to and including all terminal devices in your
home. Telco refers to this as the IW and considers it
subscriber owned, meaning if there is ever a problem that
degrades or eliminates your phone service from within the IW
its up to you to fix. |
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IP
address |
Any
computing device that uses the Internet must be assigned an
Internet or IP address. All workstations on a given IP
network use the same IP network number, and each workstation
has a unique IP host address and an optional subnetwork
number. The network and subnetwork numbers together are used
for routing, while the host number is used to address an
individual host within the network or subnetwork. |
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Local
loop |
The
local loop is the term for the line between your house, and
the local switching center. Since telephone travels on
twisted pair, you can imagine one phone company line to your
house as a big loop of wire, hence the name. |
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Maximum DSL speeds |
Maximum DSL speed is a function of distance, the gauge
(thinness) of the phone wire used in your locale and the DSL
technology employed. The fastest DSL now commonly available
is ADSL, and it offers maximum download speeds of up to
7.1mbps and around 1.1m upload. Most residential ADSL is
limited to 90-680k for download, depending on the Telco.
SDSL currently has a max of 1.5mbps, but that is both up and
down (symmetric). |
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NIC (Network
Interface Card) |
The
circuit board or other form of computer hardware which
serves as the interface between a computer, or other form of
communicating. |
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Ordering process |
Unlike a dial-up Internet account, the ordering and
installation of a DSL line is lot more complex. The ordering
process would typically involve you locating an ISP that can
offer you DSL, and then contacting them by phone or email.
Some ISPs have online query forms that allow you to
pre-qualify by entering your zip code and/or phone number,
which they check against thier database to ascertain if your
zone is lit up yet. When looking for DSL service, you should
be aware of how they intend to deliver you service. Whether
it is dynamic IP, or static IP. Also what model of CPE
(customer premise equipment) they propose. |
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Point of Demarcation |
The
point near your premise where the responsibility of the
phone company ends, and the CLEC begins. |
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POTS |
Plain Old Telephone System! |
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Router |
A
router is a network layer device that uses one or more
algorithms to determine the optimal path along which data
should be forwarded. Routers forward packets from one
network to another based on network layer information.
Routers are occasionally called gateways, but traditional
gateways do not translate data. |
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Twisted-pair |
A
common form of copper cabling used for telephony and data
communications. It consists of two copper lines twisted
around each other; the twisting protects the communications
from electromagnetic frequency and radio frequency
interference. |
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Static IP |
A
fixed IP makes it easier to operate servers, as you can
happily assign a domain name to it, and hand out business
cards listing the name, without finding it has changed the
next day. |
