Operation Manual

AT-RG213 Residential VoIP Gateway - SIP Software Reference Manual
SIP Software Release 6-0-0
J613-M0524-00
110
IP datagram The fundamental unit of information passed across the
Internet. It contains a source and destination address along with data and a
number of fields which define such things as the length of the datagram, the
header checksum, and flags to say whether the datagram can be (or has
been) fragmented.
IP interface An entity representing an IP layer attached to a layer 2 interface
and all information the IP routing algorithm needs to know to use the layer 2
interface to transmit datagrams over that physical connection. An IP
interface consists of one or more IP logical interfaces.
IP logical interface An entity which represents an IP layer interface and
holds all network layer specific information such as network address, mask,
metric, etc. Multiple logical interfaces can be bundled together in a single IP
interface.
ISDN Integrated Services Digital Network. A technology which combines voice
and digital network services in a single medium, making it possible for
telecommunications providers to offer customers digital data services as
well as voice connections through a single ‘‘wire’’. The standards that define
ISDN are specified by CCITT.
IS-IS Intermediate System-Intermediate System. The OSI interior gateway
protocol for exchanging routing information between routers within an
autonomous system.
ISO International Organisation for Standardisation. An international body
that develops standards in many areas, including network protocols. It is
best known for the seven-layer OSI (Open Systems Interconnection) suite of
network protocols.
ITS
Internet telephony service provider
ITU-T International Telecommunication Union - Telecommunications Sector
L
LAN Local Area Network. Any physical network technology (such as
Ethernet) that operates at high speed (typically 10 Mbits per second or more)
over short distances (up to a few kilometres). See WAN.
layer Communication networks for computers may be organized as a set of
more or less independent protocols, each in a different layer (also called
level).
The lowest layer governs direct host-to-host communication between the
hardware on different hosts; the highest layer consists of user applications.
Each layer builds on the layer beneath it. For each layer, programs at
different hosts use protocols appropriate to the layer to communicate with
each other. TCP/IP has five layers of protocols; OSI has seven. The
advantages of different layers of protocols is that the methods of passing
information from one layer to another are specified clearly as part of the
protocol suite, and changes within a protocol layer are prevented from