Digital Equipment RapidPrint 500, Reference Manual

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repeater A network device that repeats signals from one cable onto one or more
other cables, while restoring signal timing and waveforms. Repeaters are
the most common way to connect local networks together, and can pro-
vide either
Thinwire or Thickwire connections. They are commonly used
to create larger local networks up to a certain limit based on the number
of repeaters and the length of the cables.
RFC Request For Comments. A standard document describing protocols, sys-
tems, or procedures used by the Internet community. For example, the IP
network protocol is detailed in an RFC (RFC 791), as are SNMP, TCP, Fin-
ger, BOOTP, and the Domain name system. Information on obtaining
RFC’s is available from NIC@NIC.DDN.MIL.
Rlogin Rlogin is an application that provides a terminal interface between (usu-
ally UNIX) hosts using the
TCP/IP network protocol. Unlike Telnet ,
Rlogin assumes the remote host is or behaves like a UNIX machine.
Rlogin can also be configured to disable login password checking, so
should be used with care. See your host’s documentation, especially
regarding the .rhosts and hosts.equiv files, for more information.
ROM Read-Only memory. A memory device that retains its information even
when power to it is removed. A ROM version of the RapidPrint 500 does
not need to
download code, since it carries the entire executable code in
ROM and thus never needs to reload it. Frequently the ROM is provided
as “flash ROM,” which can be reprogrammed if the software needs
updating.
router On large networks, some hosts are connected to more than one network
and are designated routers—they route messages on the net to the correct
“place.” They may send an incoming message to an adjacent network if
they do not know the destination host by name, or they may send it right
to the intended destination. On cross-country networks, a message may
go through several routers before arriving at its final destination.
rwho A UNIX feature that enables network hosts to know what users and sys-
tems are on the network without actively connecting to them. If rwho is
enabled on a host, it both sends and receives network broadcasts contain-
ing this information. The packets generally contain the host’s name, IP
address, and the number and names of the users on the system.
Because the broadcasts are periodic (typically 30 seconds to 2 minutes),
hosts that are seen with rwho and then removed from the local host table
will reappear later. Rwho usually has to be enabled explicitly on the host
system, and may not be enabled on large network environments where
the extra network traffic is unacceptable. In this case hosts can be added
to the RapidPrint 500’ host table by hand.
service Any device on a network that can be connected to and accessed, such as a
printer, modem, or a remote computer. Network users can generally see
the services available on the network because the
nodes that provide
these services “advertise” them to the world. In the case of LAT, each ser-
vice node sends out occasional network messages called
multicasts
describing what services it is providing and which users are connected to
them. Note that the concept of services is one specific to
LAT and local
area networks. TCP/IP and other wide area networks have no such facil-
ity. The service will occasionally be used to refer to anything that can be
connected, whether LAT or not.