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Basic Advanced TCP/IP Wireless
VT2400/VT2500 Series Voice Gateway User Guide
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CableHome
A project of CableLabs and technology suppliers to develop interface specifications for extending
high-quality cable-based services to home network devices. It addresses issues such as device
interoperability, QoS, and network management. CableHome will enable cable service providers to
offer more services over HFC. It will improve consumer convenience by providing cable-delivered
services throughout the home.
CableLabs
A research consortium that defines the interface requirements for cable modems and acknowledges
that tested equipment complies with DOCSIS.
cable modem
A device installed at a subscriber location to provide data communications over an HFC network.
Unless otherwise specified, all references to “cable modem” in this documentation refers to DOCSIS
or Euro-DOCSIS cable modems
only
.
cable modem
configuration
file
File containing operational parameters that a cable modem or gateway downloads from the cable
provider’s TFTP server during registration.
circuit-switched
Network-connection scheme used in the traditional PSTN telephone network where each connection
requires a dedicated path for its duration. An alternative is packet-switched.
CLASS
Customer Local Area Signaling Service. One of an identified group of network-provided enhanced
services. A CLASS group for a given network usually includes several enhanced service offerings,
such as incoming-call identification, call trace, call blocking, automatic return of the most recent
incoming call, call redial, and selective forwarding and programming to permit distinctive ringing for
incoming calls.
Class C network
An IP network containing up to 253 hosts. Class C IP addresses are in the form
“network.network.network.host.”
client
In a client/server architecture, a client is a computer that requests files or services such as file transfer,
remote login, or printing from the server. Also called a CPE.
On a WLAN, a client is any host that can communicate with the access point. A wireless client is also
called a “station.”
CMTS
A cable modem termination system is a device in the cable system headend that interfaces the HFC
network to local or remote IP networks to connecting IP hosts, cable modems or gateways, and
subscribers. It manages all cable modem bandwidth. It is sometimes called an edge router.
CNR
carrier to noise ratio
coaxial cable
(coax)
A type of cable consisting of a center wire surrounded by insulation and a grounded shield of braided
wire. The shield minimizes electrical and radio frequency interference. Coaxial cable has high
bandwidth and can support transmission over long distances.
CODEC
COmpression/DECompression. A software-only or a hardware-assisted scheme that is used to
process digital video or audio files. The amount of data required to represent moving pictures with
sound is reduced by a CODEC, which normally discards redundant data on compression.
CoS
Class of service traffic management or scheduling functions are performed when transferring data
upstream or downstream on HFC.
CPE
Customer premise equipment, typically computers, printers, etc., are connected to the cable modem
or gateway at the subscriber location. CPE can be provided by the subscriber or the cable provider.
Also called a client.
crosstalk
Undesired signal interfering with the desired signal.
CSMA/CD
carrier sense multiple access with collision detection
