Specifications

AVM Access Server – Glossary 133
“Well-known ports” are destination port numbers that are reserved for
common network services and applications by IANA, the Internet Assigned
Numbers Authority. Well-known ports are in the range from 1 to 1023.
PPP over ISDN (Point-to-Point Protocol)
A communication protocol for circuit-switched networks such as ISDN
that provide protocol-independent communication on ISO OSI Layer 2.
PPP over ISDN incorporates a collection of subordinate standards and
protocols. These describe the structure of data transport for a variety of
networks. These standards are primarily intended to provide interoper-
ability, ensuring that different manufacturers’ devices with different
sets of features can communicate by a uniform method. PPP over ISDN
is specified in RFC 1618.
Proxy ARP
Proxy ARP is not a protocol, but rather an extension of the AVM Access
Server that responds to ARP requests for remote hosts on the basis of
the current routing table. The AVM Access Server answers ARP requests
in place of the host actually addressed by the IP number, if that host is
connected over ISDN. This allows the remote users and networks con-
nected to the LAN over ISDN to share the same IP address range as the
AVM Access Server’s LAN subnet. The result is a simpler network con-
figuration.
RADIUS (Remote Authentication Dial-In User Service)
A standard IP-based service for authentication and accounting (i.e., re-
cording of cost and use data) for dial-in users. When a remote user dials
in, the AVM Access Server forwards a query with the user’s name and
password to the RADIUS server. This server performs the authentication
check and returns confirmation, along with a number of configuration
parameters for the user's connection, such as an IP address. The RADIUS
protocol is defined in RFC 2058, and RADIUS accounting in RFC 2139.
RIP (Routing Information Protocol)
The Routing Information Protocol (RIP) is used by routers to exchange
network configuration information (for IP and IPX). A RIP router is a
computer or other hardware component that forwards IP packets be-
tween connected networks, and shares its routing information, such as
network addresses. RIP allows the router to exchange route informa-
tion with other routers in the network environment. When a router de-
tects any change in the structure of the internetwork (such as another