Nortel Networks Remote Gateway 50 - Manual (Page 252)

Page 252 of 258 List of terms
553-3001-207 Standard 2.00 January 2006
provided by ESA. Please note, however, that the ESA feature is also generally
useful for users who are not subject to legislation, and is broad enough to be
used in different countries. For example, it will be appreciated by any
customer who wants to route emergency calls in a special manner, or who
wants to be notified when a telephone user makes an emergency call. It would
also appeal to a customer who wishes to have ESA calls answered onsite,
on the business premises, rather than being forwarded to the Public Services
Answering Point (PSAP). Refer to Emergency Services Access: Description
and Administration (553-3001-313) for complete information.
Gatekeeper
The Gatekeeper is a separate application on an IP network that directs IP
traffic to all the systems on the network. Parameters for both the main office
and SRG must be assigned to all gatekeepers active on the network. If the
Gatekeeper is down, the SRG attempts to connect to the Alternate
Gatekeeper, if there is one. If the Alternate Gatekeeper is down as well, or
there is no Alternate Gatekeeper, the SRG IP Phones remain registered with
the main office but calls cannot be sent to the SRG.
gateway
In networking, a combination of hardware and software that links two
different types of networks. Gateways between e-mail systems, for example,
enable users on different e-mail systems to exchange messages.
H.323
A standard approved by the International Telecommunication Union (ITU)
that defines how audiovisual conferences data is transmitted across networks.
In theory, H.323 enables users to participate in the same conference even
though they are using different video conferencing applications. Although
most video conferencing vendors have announced that their products
conform to H.323, it is too early to say whether such adherence actually
results in interoperability.
IP
Abbreviation of Internet Protocol, pronounced as two separate letters. IP
specifies the format of packets, also called datagrams, and the addressing
scheme. Most networks combine IP with a higher-level protocol called