# US 11,909,596 B2 · Connections and accesses for hierarchical path computation element (PCE) > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,909,596 B2 - Document ID: US11909596B2 - Status: Granted - Kind: B2 - Application number: 17/876,868 - Filed: 2022-07-29 - Published: 2022-11-17 - Granted: 2024-02-20 - Earliest claimed: 2016-07-06 - Assignees: Futurewei Technologies, Inc. - Applicants: Futurewei Technologies, Inc. - Inventors: Huaimo Chen - Web page: https://patentgrep.com/patent/US11909596B2 ## CPC - H04L 41/12: Discovery or management of network topologies - H04L 41/044: comprising hierarchical management structures - H04L 43/08: Monitoring or testing based on specific metrics, e.g. QoS, energy consumption or environmental parameters - H04L 45/02: Topology update or discovery - H04L 45/42: Centralised routing - H04L 45/04: {Interdomain routing, e.g. hierarchical routing} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract 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. ## Claims ### Claim 1 A path computation element (PCE) comprising: a network interface for enabling communications over a network; memory for storing executable instructions; a processor configured to execute the executable instructions to: establish communication between the PCE and at least one first child PCE, wherein the PCE is configured as a parent PCE to a first set of child PCEs comprising the at least one first child PCE, wherein each of the at least one first child PCE is responsible for a first domain in a set of first domains, and wherein the at least one first child PCE is configured as a second parent PCE to a second set of child PCEs comprising at least one second child PCE, wherein each of the at least one second child PCE is responsible for a second domain in a set of second domains; receive domain connection information from the at least one first child PCE, wherein the domain connection information comprises a first set of domain connection information corresponding to the set of first domains; and construct an abstract domain topology based on the domain connection information. ### Claim 2 (depends on 1) The PCE of claim 1, wherein the domain connection information comprises a second set of domain connection information corresponding to the set of second domains. ### Claim 3 (depends on 2) The PCE of claim 2, wherein the domain connection information excludes inter-domain links and area border routers (ABRs) that connect between the set of second domains associated with the second set of child PCEs. ### Claim 4 (depends on 1) The PCE of claim 1, wherein the domain connection information for the first domain of each of the at least one first child PCE is communicated by each of the at least one first child PCE to the PCE using a newly defined message comprising a new connection and access object that includes new object types comprising an inter-domain link object, an area border router (ABR) object, an access Internet Protocol Version 4 (IPv4) prefix object, and an access Internet Protocol Version 6 (IPv6) prefix object. ### Claim 5 (depends on 1) The PCE of claim 1, wherein the domain connection information comprises a domain identifier of the first domain of a first child PCE, inter-domain links and area border routers (ABRs) of the first domain of the first child PCE to adjacent domains, and wherein the domain connection information comprises access points within the first domain of the first child PCE. ### Claim 6 (depends on 5) The PCE of claim 5, wherein the inter-domain links include point-to-point (P2P) links connecting two autonomous system border routers (ASBRs) in two different first domains, and broadcast links connecting multiple ASBRs in a number of first domains. ### Claim 7 (depends on 6) The PCE of claim 6, wherein the domain connection information for the P2P links comprises a link type, a local Internet Protocol (IP) address, a remote IP address, a traffic engineering metric, a maximum bandwidth, a maximum reservable bandwidth, an administrative group, and shared risk link groups (SRLG). ### Claim 8 (depends on 6) The PCE of claim 6, wherein the domain connection information for the broadcast links comprises a link type, a local Internet Protocol (IP) address with mask length, a traffic engineering metric, a maximum bandwidth, a maximum reservable bandwidth, an administrative group, and shared risk link groups (SRLG). ### Claim 9 (depends on 1) The PCE of claim 1, wherein the domain connection information for the first domain of each of the at least one first child PCE is communicated by each of the at least one first child PCE to the PCE by extending a path computation element communication protocol (PCEP) notification message to include a new notification-type (NT) and notification-value (NV) of a notification object in the PCEP notification message. ### Claim 10 (depends on 9) The PCE of claim 9, wherein the NV indicates whether connections and access points indicated by type-length-values (TLVs) in the notification object within the PCEP notification message are to be updated or withdrawn. ### Claim 11 (depends on 10) The PCE of claim 10, wherein four TLVs are defined for the connections and access points, and wherein the four TLVs comprise a domain link TLV, Router-identifier (ID) TLV, access Internet Protocol Version 4 (IPv4) prefix TLV, and access Internet Protocol Version 6 (IPv6) prefix TLV. ### Claim 12 A path computation element (PCE) comprising: a network interface for enabling communications over a network; memory for storing executable instructions; a processor configured to execute the executable instructions to: establish communication between the PCE and a parent PCE, wherein the PCE is configured as a first child PCE to the parent PCE, wherein the PCE is configured as a second parent PCE to a second set of child PCEs comprising at least one second child PCE, wherein each second child PCE in the second set of child PCEs is responsible for a second domain in a set of second domains; and send domain connection information comprising a first set of domain connection information corresponding to a first domain of the PCE to the parent PCE. ### Claim 13 (depends on 12) The PCE of claim 12, wherein the domain connection information is communicated by the PCE to the parent PCE by extending a path computation element communication protocol (PCEP) notification message to include a new notification-type (NT) and notification-value (NV) of a notification object in the PCEP notification message. ### Claim 14 (depends on 13) The PCE of claim 13, wherein the notification-value (NV) indicates whether connections and access points indicated by type-length-values (TLVs) in the notification object within the PCEP notification message are to be updated or withdrawn. ### Claim 15 (depends on 14) The PCE of claim 14, wherein the domain connection information comprises a domain identifier of the first domain of the PCE, inter-domain links and area border routers (ABRs) of the first domain of the PCE to adjacent domains, and wherein the domain connection information comprises access points within the first domain of the PCE. ### Claim 16 (depends on 15) The PCE of claim 15, wherein the inter-domain links include point-to-point (P2P) links and broadcast links, wherein the P2P links connect an autonomous system border router (ASBR) in the first domain of the PCE and a second ASBR in a different domain, and wherein the broadcast links connect the ASBR in the first domain of the PCE to multiple ASBRs in a number of different domains. ### Claim 17 (depends on 16) The PCE of claim 16, wherein the domain connection information for the P2P links comprises a link type, a local Internet Protocol (IP) address, a remote IP address, a traffic engineering metric, a maximum bandwidth, a maximum reservable bandwidth, an administrative group, and shared risk link groups (SRLG). ### Claim 18 (depends on 16) The PCE of claim 16, wherein the domain connection information for the broadcast links comprises a link type, a local Internet Protocol (IP) address with mask length, a traffic engineering metric, a maximum bandwidth, a maximum reservable bandwidth, an administrative group, and shared risk link groups (SRLG). ### Claim 19 (depends on 12) The PCE of claim 12, wherein the domain connection information communicated to the parent PCE by the PCE comprises a second set of domain connection information corresponding to the second domain of the at least one second child PCE, and wherein the first set of domain connection information and the second set of domain connection information is abstracted as a single cloud.