IBM SC30-3865-04 User Manual

Page 499

VIrtual NEtworking System (VINES). The network
operating system and network software from Banyan
Systems, Inc. In a VINES network, virtual linking allows
all devices and services to appear to be directly
connected to each other, when they may actually be
thousands of miles apart. See also

StreetTalk

virtual route (VR). (1) In SNA, either (a) a logical
connection between two subarea nodes that is
physically realized as a particular explicit route or (b) a
logical connection that is contained wholly within a
subarea node for intranode sessions. A virtual route
between distinct subarea nodes imposes a transmission
priority on the underlying explicit route, provides flow
control through virtual route pacing, and provides data
integrity through sequence numbering of path
information units (PIUs). (2) Contrast with

explicit route

(ER)

. See also

path

and

route extension (REX)

wide area network (WAN). (1) A network that provides
communication services to a geographic area larger
than that served by a local area network or a
metropolitan area network, and that may use or provide
public communication facilities. (T)

(2) A data

communication network designed to serve an area of
hundreds or thousands of miles; for example, public and
private packet-switching networks, and national
telephone networks. (3) Contrast with

local area network

(LAN)

and

metropolitan area network (MAN)

wildcard character. Synonym for

pattern-matching

character

X.21. An International Telegraph and Telephone
Consultative Committee (CCITT) recommendation for a

general-purpose interface between data terminal
equipment and data circuit-terminating equipment for
synchronous operations on a public data network.

X.25. (1) An International Telegraph and Telephone
Consultative Committee (CCITT) recommendation for
the interface between data terminal equipment and
packet-switched data networks. (2) See also

packet

switching

Xerox Network Systems (XNS). The suite of internet
protocols developed by the Xerox Corporation. Although
similar to TCP/IP protocols, XNS uses different packet
formats and terminology. See also

Internetwork Packet

Exchange (IPX)

zone. In AppleTalk networks, a subset of nodes within
an internet.

Zone Information Protocol (ZIP). In AppleTalk
networks, a protocol that provides zone management
service by maintaining a mapping of the zone names
and network numbers across the internet on the session
layer.

zone information table (ZIT). A listing of network
numbers and their associated zone name mappings in
the internet. This listing is maintained by each internet
router in an AppleTalk internet.

Glossary

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