China Mobile Huawei China Mobile Huawei ZTE Corporation In some networks, the cross-layer planning and optimization is considered more efficient than independent planning and operation of the layer-3 and the underlying networks in terms of resource utilization and SLA assurance. This document extends the PCEP SRv6 for inter-layer network, which enable the PCE to instantiate candidate paths comprising both the layer-3 network segments and underlay network segments.