Digital Equipment RapidPrint 500, Reference Manual

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SNMP Simple Network Management Protocol. SNMP allows a TCP/IP host run-
ning an SNMP application to query other nodes for network-related sta-
tistics and error conditions. The other hosts, which provide SNMP agents,
respond to these queries and allow a single host to gather network statis-
tics from many other network nodes. The terminal server provides this
SNMP agent only; it cannot generate queries to other hosts. It only
responds to them.
subnet mask The RapidPrint 500 supports Telnet connections across networks through
the use of
gateways . A gateway host will forward messages across net-
work boundaries. At connection time, however, the RapidPrint 500 must
decide whether the remote machine is on the local network (and can be
accessed directly) or whether it is on a remote network (and must be
accessed through a gateway). It does this with the subnet mask set up for
the server. The RapidPrint 500 uses the mask as a filter; if the RapidPrint
500’s IP address and the remote IP address appear the same after the fil-
ter, the remote host is assumed to be on the same local network. Other-
wise, the gateway is used. The mask itself is a list of bits that should be
enabled in the result—a 1 in the mask means to let that bit in the IP
address through, and 0 means do not.
For example, address 192.1.2.22 with mask 255.255.0.0 becomes 192.1.0.0.
For network purposes, host 192.1.5.12 is on the same network, based on
the mask specified. In this case, a gateway would not be accessed. A host
at 192.8.12.34 would be considered on a different network, however, since
the network mask comes out to be 192.8.0.0, and this does not match the
previous two masks. In this second case, the gateway host would be
used—if it had not been defined, the connect attempt would fail. If the
subnet mask is not set explicitly (with the Set Serve Subnet command),
the RapidPrint 500 will assume a mask based on the RapidPrint 500’s IP
address and thus the apparent network type. This mask will be
255.255.255.0 for most (19x.x.x.x and 2xx.x.x.x) IP addresses.
tap A tap usually refers to a point on the network backbone where other
devices can be attached. If the network is thought of as a freeway, the taps
on the network are the on and off ramps to the freeway (and like freeway
access ramps, taps are usually where network problems occur). Taps may
be of several types, including simple “T” connectors or “Vampire” taps
that attach directly to a network cable.
TCP/IP TCP and IP are the standard network protocol in UNIX environments.
They are almost always implemented and used together and called TCP/
IP. TCP/IP is an extremely flexible protocol, allowing reliable access to
over four billion possible nodes anywhere in the world. It also allows
many protocols to run on top of it, notably
Telnet , Rlogin , and TFTP .
TCP/IP support may be integral to an operating system, as in UNIX, or it
can be a separate product added later as on VMS machines.
Telnet Telnet is an application that provides a terminal interface between hosts
using the
TCP/IP network protocol. It has been standardized so that Tel-
netting to any host should give you an interactive terminal session,
regardless of the remote host type or operating system. Note that this is
very different from the
LAT software, which allows only local network
access to LAT hosts only.
10BASE2 Thinwire network cable.