Backbone Network Definition/Meaning:
The underlying nodes of a multilevel distributed network, providing
communication services for the rest of the network (the hosts). The backbone
network usually consists of dedicated packet, message, or circuit switches
connected by high-capacity trunk circuits, along with some special diagnostic
and control equipment. An example is the ARPANETs IMP subnet.
An
important requirement for backbone networks is that they must be extremely
reliable. For this reason they are usually built out of homogeneous (essentially
similar) processors and run by a centralized administration, although the rest
of the network may be highly heterogeneous and under distributed authority.
Distributed procedures are often used to control the operation of the backbone
network in order to reduce the possibility dial a single failure might disrupt
the entire network. When a central control system is used, there is usually a
standby system ready to take over when the active system fails.
Backbone networks are often characterized by distributed traffic patterns Packet
switching may be used internally by backbone networks to take advantage of these
traffic patterns, even though the backbone network may present a
circuit-switching appearance to external hosts (see virtual connection).
Traffic-pattern analysis may be used to construct backbone networks that
minimize certain network parameters, such as average delay, circuit costs, etc.
Backbone networks may themselves be multilevel, incorporating low-capacity
terrestrial links, high-capacity terrestrial links, and satellite links.
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