US Patent 11405283 Connections and accesses for hierarchical path computation element (PCE)

Disclosed herein are various embodiments for constructing an abstract domain topology. In one embodiment, a Path Computation Element (PCE) is configured as a parent PCE to at least one child PCE. Each of the child PCEs is responsible for providing path computational services for a domain. Communication is established between the parent PCE and the at least one child PCE. The parent PCE receives from each of its child PCEs domain connection information corresponding to the domain of each child PCE. The parent PCE builds and maintains an abstract domain topology based on the domain connection information that it receives from its child PCEs. In one embodiment, the domain connection information is communicated from the child PCE to the parent PCE by adding a new notification-type (NT) and notification-value (NV) to a notification object in a Path Computation Element Communication Protocol (PCEP) notification message.