Operation Manual

NetWAYS/ISDN – Glossary 59
incurred. AO/DI dynamically enables one or more B channels
(Dynamic ISDN) depending on the amount of data to be
transmitted.
ARP (Address Resolution Protocol)
The Address Resolution Protocol, or ARP, is part of the TCP/IP
protocol suite. ARP is used dynamically to obtain the Ether-
net hardware address (called the MAC address) of the inter-
face that corresponds to a given IP address. This takes place
automatically, and is normally transparent to applications
and users.
In order for TCP/IP network communication to take place, the
transmitting station must obtain the hardware address corre-
sponding to the IP destination address. To obtain the hard-
ware address, the transmitting station sends an ARP request
packet containing the IP address of the desired destination.
This packet is broadcast to all ARP-capable stations on the
network, and the one with the IP address requested re-
sponds to it with an ARP reply packet. The sender then stores
the IP address—hardware address association in its ARP
cache.
Authentication
Authentication refers to identifying a remote system by veri-
fying its login information (name and password) on estab-
lishing incoming and outgoing connections. NetWAYS/ISDN
uses authentication not only to prevent unauthorized ac-
cess, but also to ascertain which remote user settings to
apply if incoming call assignment by CLI number is not acti-
vated. For PPP connections PAP and CHAP are available as
authentication protocols.
In NetWAYS/ISDN, authentication of the remote system can
be activated or deactivated for each call destination, and the
authentication protocol used can be specified for each
destination separately. For each authentication protocol, a
name and password must be configured and communicated
to the remote site. If the remote server also demands
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