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In one embodiment, a particular device within a client-layer network maintains client-layer topology information including server-layer Shared Risk Link Group (SRLG) information of server-layer devices and links in a server-layer network associated with client-layer links and client-layer nodes in the client-layer network. A determination is made to discover if there is an alternative client-layer path to an established client-layer path between a first packet switching device and a second packet switching device if all server-layer resources of any particular server-layer SRLG of a plurality of total server-layer SRLGs associated with the established client-layer path become unavailable. In one embodiment, the plurality of total server-layer SRLGs includes: an SRLG of a same optical node, an SRLG of a same optical fiber, an SRLG of co-located plurality of optical nodes, and/or an SRLG of co-located plurality of optical fibers.