ADS Technologies SBG1000 manual 149, Pptp, Pstn, Qam, Qpsk

Overview Installation Troubleshooting Contact FAQ Specifications Glossary License

Configuration: Basic Gateway TCP/IP Wireless Print Server USB

port mirroring A feature that enables one port (source) on the SBG1000 to be copied to another port (destination) to be studied. The destination mirrors the transmitted (from) or received (to) data on the source port to enable the person managing the network to monitor activity.

port triggering A mechanism that allows incoming communication with specified applications. Primarily used for gaming applications.

PPPPoint-to-Point Protocol is used to transport other protocols, typically for simple links over serial lines. It is most commonly used to access the Internet with a dial-up modem.

PPTP	Point-to-Point Tunneling Protocol encapsulates other protocols. It is a new technology to create VPNs
	developed jointly by several vendors.
private IP	An IP address assigned to a computer on the SBG1000 LAN by the DHCP server on the SBG1000 for
address	a specified lease time. Private IP addresses are used by the SBG1000 LAN only; they are invisible to
	devices on the Internet. See also public IP address.
protocol	A formal set of rules and conventions for exchanging data. Different computer types (for example PC,
	UNIX, or mainframe) can communicate if they support common protocols.
provisioning	The process of autodiscovery or manually configuring a cable modem on the CMTS.
PSTN	The public switched telephone network is the traditional circuit-switched, voice-oriented telephone
	network. See also POTS.
public IP	The IP address assigned to the SBG1000 by the cable provider. A public IP address is visible to
address	devices on the Internet. See also private IP address.

Q

QAM	Quadrature Amplitude Modulation uses amplitude and phase modulation to encode multiple bits of
	data in one signaling element. QAM achieves faster data transfer than amplitude or phase modulation
	alone, but the signal is more prone to errors caused by noise. QAM requires a transmission circuit with
	a higher CNR than alternate modulation formats such as QPSK. Two types of QAM are:
	• 16 QAM encodes four bits per symbol as one of 16 possible amplitude and phase combinations.
	• 64 QAM encodes six bits per symbol as one of 64 possible amplitude and phase combinations.
QPSK	Quadrature Phase Shift Key (QPSK) modulation sends two bits of information per symbol period with
	one symbol 90 degrees out of phase with other symbols. The four constellation points represented by
	the coordinates (0,0 - 0,1 - 1,0 - 1,1) represent the four possible combinations.
QoS	Quality of service describes the priority, delay, throughput, and bandwidth of a connection.

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