Lantronix ETS, Справочное руководство

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Glossary ROM
Glossary-7
ROM Read-Only Memory. This kind of memory device retains its information even
when its power source is removed. A ROM version of the ETS does not need
to download code, since it carries the entire executable code in ROM.
Frequently the ROM is provided as flash ROM, which can be reprogrammed
if the software needs to be updated.
router Hosts on large networks that are connected to more than one network and route
messages to the correct destination nodes. Routers 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 systems
are on the network without actively connecting to them. If rwho is enabled on
a host, it both sends and receives network broadcasts containing this
information. The packets generally contain the host’s name, IP address, and the
number and names of the users on the system. The ETS listens for these
broadcasts and adds the hosts to the local host table, eliminating the need to
nameserve for their names.
Because the broadcasts are periodic (typically 30 seconds to two 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 local host
table by hand.
SAP Service Advertising Protocol. SAP packets, along with RIP packets, allow the
Server to broadcast its known routes and services to the network and obtain this
information from other routers on the network.
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 service node sends out
occasional network messages called multicasts describing what services it is
providing and which users are connected to them.
The concept of services is specific to LAT and local area networks. TCP/IP
and other wide area networks have no such facility. The service will
occasionally be used to refer to anything that can be connected, whether LAT
or not.