Operation Manual

NT/MPRI – Glossary 114
procedures are supported. In the NT/MPRI you may specify the proce-
dure by which each remote site must identify itself (“Authentication at
the Local Site”). A name and a password must be configured for each
procedure, and these must be communicated to the call destina-
tion/user. If the remote site's system also requires authentication in-
formation from the NT/MPRI (“Authentication at the Remote Site”), you
can enter the correct name and password (received from the remote
site) into the call destination/user settings.
B Channel
An ISDN Basic Rate Interface (BRI) consists of two B channels and a D
channel. An ISDN Primary Rate Interface (PRI) consists of thirty B chan-
nels and one D channel. User data is transmitted on the B channels at
64 kbit/s. The connection speed can be increased by bundling the B
channels.
CHAP (Challenge Handshake Authentication Protocol)
One of two authentication protocols. To perform an authentication, the
local and remote sites must have the name and password to be used
entered in their configuration. Under CHAP, the site requesting the au-
thentication generates a message from the user name and a random
value according to a defined encryption algorithm, and sends the mes-
sage to the remote site. The remote site produces a new value out of
the message and the password, also using a preset algorithm, and
sends this value back. The first site now checks whether the value it
produces from the original message and the password agrees with the
value the remote site sent back. If it does, the connection is set up. As
the password itself ist not transmitted during this process, CHAP can
be considered as safe. CHAP is defined in RFC 1334 and RFC 1994.
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