Cisco Cisco Access Registrar 3.5 - Manual (Page 74)

Glossary
GL-8
Cisco Access Registrar 3.5 Concepts and Reference Guide
OL-2683-02
T
TACACS Terminal Access Controller Access Control System, a an authentication server that validates user IDs
and passwords, thus controlling entry into systems.
Telnet A service that lets you log in to a system over a network just as though you were logging in from a
remote character terminal attached to the system. It is commonly used to provide an Internet service
that is exactly the same as the one you would get if you dialed into the system directly with a modem.
Trap A network message of a specific format issued by an SNMP entity on behalf of a network management
agent application. A trap is used to provide the management station with an asynchronous notification
of an event.
Tunnel A tunnel is defined by an LNS-LAC pair. The tunnel carries PPP datagrams between the LAC and the
LNS; many sessions can be multiplexed over a single tunnel. A control connection operating in band
over the same tunnel controls the establishment, release, and maintenance of sessions and of the tunnel
itself.
Tunnel Network
Server A server that terminates a tunnel. In PPTP terminology, this is known as the PPTP Network Server
(PNS). In L2TP terminology, this is known as the L2TP Network Server (LNS).
U
UDP User Datagram Protocol, a data packet protocol.
User List The list of users registered for dial-in access.
User Record The UserRecord contains all the information that needs to be accessed at runtime about a particular
user. This enables it to be read in one database operation in order to minimize the cost of authenticating
the user. The UserRecord is stored as an encrypted string in the MCD database, because it contains the
user’s password, amongst other things.
Users Users are represented by entities in specific UserLists. See User Record.
V
Vendor Each NAS has a vendor associated with it. A vendor may specify attributes for the NAS that are not
part of the standard specification.
VHG Virtual Home Gateway—a Cisco IOS component that terminates PPP sessions. It is owned and
managed by the service provider on behalf of its customer to provide access to remote users of that
customer’s network. a single service provider device (router) may host multiple VHGs of different
customers. a VHG may be dynamically brought up and down based on the access pattern of the remote
users. Note that there is no single IOS feature called the VHG; it is a collection of function and features
(PPP, virtual profiles, VRFs, etc.).