Operation Manual

AT-RG213 Residential VoIP Gateway - SIP Software Reference Manual
SIP Software Release 6-0-0
J613-M0524-00
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broadcast is routed to the specified network where it is broadcast to all
machines on that network.
DHCP Dynamic Host Configuration Protocol. TCP/IP protocol that enables PCs
and workstations to get temporary or permanent IP addresses (out of a pool)
from centrally-administered servers.
DNS Domain Name System. The distributed name/address mechanism used
in the Internet. It comprises distributed online databases that contain
mappings between human-readable names and IP addresses, and servers
which provide translation services to client applications.
domain A part of the DNS naming hierarchy. Syntactically, an Internet
domain name consists of a sequence of names (labels) separated by periods
(dots), e.g., “machine.company.com”. See DNS.
dotted decimal notation The syntactic representation for a 32-bit integer
that consists of four 8-bit numbers written in base 10 with periods (dots)
separating them. It is used to represent IP addresses in the Internet, e.g.
172.16.9.197.
DSP Digital Signal Processor. Specialized computer chip designed to perform
speedy and complex operations on digitized waveforms. Useful in
processing sound (like voice phone calls) and video.
DTMF Dual-Tone Multi-Frequency. In telephone systems, multi-frequency
signaling in which a standard set combinations of two specific voice band
frequencies, one from a group of four low frequencies and the other from a
group of four higher frequencies, are used. Although some military
telephones have 16 keys, telephones using DTMF usually have 12 keys. Each
key corresponds to a different pair of frequencies. Each pair of frequencies
corresponds to one of the ten decimal digits, or to the symbol “#” or “*”, the
“*” being reserved for special purposes.
E
encapsulation The technique used by layered protocols in which a layer
adds header information to the protocol data unit (PDU) from the layer
above. As an example, in Internet terminology, a packet would contain a
header from the physical layer, followed by a header from the network layer
(IP), followed by a header from the transport layer (TCP), followed by the
application protocol data.
EPROM Erasable Programmable Read-Only Memory. These devices contain the
system software on the router, and may need to be changed in some
circumstances to upgrade the software to a new release. They are
nonvolatile, i.e. they retain their information during power-down. See
FLASH