subnetwork

1) In IP networks, a network that shares a particular subnet address. Subnetworks are networks arbitrarily segmented by a network administrator in order to provide a multilevel, hierarchical routing structure while shielding the subnetwork from the addressing complexity of attached networks. Sometimes called a subnet. See also IP address, subnet address, and subnet mask.

2) In OSI networks, a collection of ESs and ISs under the control of a single administrative domain and using a single network access protocol.