User manual

Appendix G: Glossary
262 Cobalt Qube 3 User Manual
Integrated Services Digital Network (ISDN)
A system of digital telephone connections. This system allows data to be
transmitted simultaneously across the world using end-to-end digital
connectivity.
With ISDN, voice and data are carried by bearer channels (B channels)
occupying a bandwidth of 64 Kb/s (some switches limit B channels to a
capacity of 56 Kb/s). A data channel (D channel) handles signaling at
16 Kb/s or 64 Kb/s, depending on the type of service.
There are two basic types of ISDN service: Basic Rate Interface (BRI) and
Primary Rate Interface (PRI). BRI consists of two 64 Kb/s B channels and
one 16 Kb/s D channel for a total of 144 Kb/s. This basic service is intended
to meet the needs of most individual users.
PRI is intended for users with greater capacity requirements. Typically, the
channel structure is 23 B channels plus one 64 Kb/s D channel for a total of
1536 Kb/s. In Europe, PRI consists of 30 B channels plus one 64 Kb/s
D channel for a total of 1984 Kb/s.
Internet Corporation for Assigned Names and Numbers (ICANN)
The private (non-government) non-profit corporation that has been formed to
assume responsibility for the IP address space allocation, protocol parameter
assignment, domain name system (DNS) management and root server
system management functions. These functions were previously performed
by the Internet Assigned Numbers Authority (IANA). The U.S. government
is essentially turning over control of the Internet to ICANN, although
domain name registration performed by Network Solutions, Inc. (NSI) will
continue to be under U.S. government contract for a limited time.
Internet domain
An Internet domain is a host naming convention used to ensure that no two
individual hosts on the global Internet have the same host name. An Internet
domain should not be confused with an NT Domain.