A node (10; 20) of a fiberoptic network having optical fibers carrying WDM signals to and from said node in a plurality of directions, said node comprising: a network level module, for modular replacement of the network level module of said node, the network level module having at least one switching device (21T-24T; 21F-24F) for selectively passing WDM signals through said node from one optical fiber to another optical fiber (11-19, 70), adding local WDM signals to one or more selected optical fibers carrying WDM signals from said node, and dropping selected WDM signals from one or more selected optical fibers carrying WDM signals to said node; a local level module, for modular replacement of the local level module of said node, the local level module having a plurality of port devices (30a-30i) for converting electrical signals into WDM signals to be added at said node and converting WDM signals dropped at said node into electrical signals; and an intermediate level module, for modular replacement of devices of said node, the intermediate level module having: a network/intermediate level interface, an intermediate/local level interface, and a plurality of devices (31T-34T; 31F-34F) connected to said network level module by the network/intermediate level interface and connected to said local level module by the intermediate/local level interface, said intermediate level devices (31T-34T; 31F-34F) providing a conduit from said local level module to said network level module for said local WDM signals to be added at said node to said one or more selected optical fibers carrying WDM signals from said node and from said network level module to said local level module for said selected WDM signals dropped from said one or more selected optical fibers carrying WDM signals to said node. a network level module, for modular replacement of the network level module of said node, the network level module having at least one switching device (21T-24T; 21F-24F) for selectively passing WDM signals through said node from one optical fiber to another optical fiber (11-19, 70), adding local WDM signals to one or more selected optical fibers carrying WDM signals from said node, and dropping selected WDM signals from one or more selected optical fibers carrying WDM signals to said node; a local level module, for modular replacement of the local level module of said node, the local level module having a plurality of port devices (30a-30i) for converting electrical signals into WDM signals to be added at said node and converting WDM signals dropped at said node into electrical signals; and an intermediate level module, for modular replacement of devices of said node, the intermediate level module having: a network/intermediate level interface, an intermediate/local level interface, and a plurality of devices (31T-34T; 31F-34F) connected to said network level module by the network/intermediate level interface and connected to said local level module by the intermediate/local level interface, a network/intermediate level interface, an intermediate/local level interface, and a plurality of devices (31T-34T; 31F-34F) connected to said network level module by the network/intermediate level interface and connected to said local level module by the intermediate/local level interface, said intermediate level devices (31T-34T; 31F-34F) providing a conduit from said local level module to said network level module for said local WDM signals to be added at said node to said one or more selected optical fibers carrying WDM signals from said node and from said network level module to said local level module for said selected WDM signals dropped from said one or more selected optical fibers carrying WDM signals to said node.