# US 2017/0257307 A1 · Method and Device for Establishing Multi-Domain Dual-Home Path > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0257307 A1 - Document ID: US20170257307A1 - Status: Published application - Kind: A1 - Application number: 15/322,173 - Filed: 2014-10-13 - Published: 2017-09-07 - Earliest claimed: 2014-06-27 - Assignees: Zte Corporation - Applicants: Zte Corporation - Inventors: Gang LU; Feng SHI - Web page: https://patentgrep.com/patent/US20170257307A1 ## CPC - H04L 45/128: for finding disjoint paths - H04L 45/02: Topology update or discovery - H04L 45/04: {Interdomain routing, e.g. hierarchical routing} - H04L 45/22: {Alternate routing} - H04L 45/24: Multipath - H04L 45/50: using label swapping, e.g. multi-protocol label switch [MPLS] - H04L 67/63: Routing a service request depending on the request content or context - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Disclosed are a method and a device for establishing a multi-domain and dual-home path, herein the method includes: a client network sending information of a first dual-home path and a computation request of a dual-home separating path of the first dual-home path to a parent PCE of a serving network with which the client network is associated; the client network receiving information of the dual-home separating path responded by the parent PCE, herein the information of the dual-home separating path is computed by the parent PCE at least according to the information of the first dual-home path; and the client network establishing a second dual-home path according to the information of the dual-home separating path. ## Claims ### Claim 1 A method for establishing a multi-domain and dual-home path, comprising: a client network sending information of a first dual-home path and a computation request of a dual-home separating path of the first dual-home path to a parent Path Computation Element PCE of a serving network with which the client network is associated; the client network receiving information of the dual-home separating path responded by the parent PCE, wherein the information of the dual-home separating path is computed by the parent PCE at least according to the information of the first dual-home path; and the client network establishing a second dual-home path according to the information of the dual-home separating path. ### Claim 2 (depends on 1) The method according to claim 1, wherein, after the client network sending the information of the first dual-home path and the computation request of the dual-home separating path of the first dual-home path to the parent PCE of the serving network with which the client network is associated, the method further comprises: the parent PCE receiving the computation request and the information of the first dual-home path; the parent PCE responding to the computation request, and computing the information of the dual-home separating path according to the information of the first dual-home path; and the parent PCE sending the information of the dual-home separating path to a requester of the computation request. ### Claim 3 (depends on 2) The method according to claim 2, wherein the parent PCE responding to the computation request, and computing the information of the dual-home separating path according to the information of the first dual-home path comprises: the parent PCE performing nodes, links and Shared Risk Link Groups SRLG s separating processing by taking the information of the first dual-home path as a separating condition, and obtaining the information of the dual-home separating path. ### Claim 4 (depends on 2) The method according to claim 2, wherein the parent PCE responding the computation request, and computing the information of the dual-home separating path according to the information of the first dual-home path comprises: the parent PCE querying a plaintext inter-domain path of the first dual-home path according to the information of the first dual-home path and extracting a domain sequence according to the plaintext inter-domain path; the parent PCE computing a boundary node sequence of domains through which the dual-home separating path passes according to an inter-domain topology of the serving network, an end-to-end topology consisting of head and tail Client Edges CEs of the first dual-home path and the domain sequence taken as a separating condition; the parent PCE respectively sending a path computation request to each of child PCEs of the parent PCE according to the boundary node sequence; the parent PCE performing jointing according to received path computation responses made by each of the child PCEs to obtain the information of the dual-home separating path; and the parent PCE sending the information of the dual-home separating path to the requester of the computation request of the dual-home separating path. ### Claim 5 (depends on 4) The method according to claim 4, wherein each of the child PCEs makes a response to the path computation request according to following policies: under a situation that the dual-home separating path and the first dual-home path are overlapped in a domain governed by a current child PCE, the current child PCE performing avoidance processing on the dual-home separating path according to the information of the first dual-home path; and the current child PCE sending a path computation response obtained after the avoidance processing performing on the parent PCE. ### Claim 6 (depends on 1) The method according to claim 1, wherein, before the client network sending the information of the first dual-home path and the computation request of the dual-home separating path of the first dual-home path to the parent PCE of the serving network with which the client network is associated, the method further comprises: the client network sending a computation request of the first dual-home path to the parent PCE; the client network receiving the information of the first dual-home path responded by the parent PCE; and the client network establishing the first dual-home path according to the information of the first dual-home path. ### Claim 7 (depends on 6) The method according to claim 6, wherein, before the client network receiving the information of the first dual-home path responded by the parent PCE, the method further comprises: the parent PCE receiving the computation request of the first dual-home path; the parent PCE responding to the computation request of the first dual-home path, and computing a boundary node sequence of domains through which the first dual-home path passes according to an inter-domain topology of the serving network; the parent PCE respectively sending a path computation request to each of child PCEs of the parent PCE according to the boundary node sequence; the parent PCE respectively receiving path computation responses made by each of the child PCEs; the parent PCE performing jointing according to the received path computation responses made by each of the child PCEs to obtain the information of the first dual-home path; and the parent PCE sending the information of the first dual-home path to the requester of the computation request of the first dual-home path. ### Claim 8 A method for establishing a multi-domain and dual-home path, comprising: a parent Path Computation Element PCE in a serving network receiving information of a first dual-home path and a computation request of a dual-home separating path of the first dual-home path; the parent PCE responding to the computation request, and computing information of the dual-home separating path according to the information of the first dual-home path; and the parent PCE sending the information of the dual-home separating path to a requester of the computation request, wherein the information of the dual-home separating path is used by the requester to establish a second dual-home path. ### Claim 9 A device for establishing a multi-domain and dual-home path, located in a client network, comprising: a sending module arranged to send information of a first dual-home path and a computation request of a dual-home separating path of the first dual-home path to a parent Path Computation Element PCE of a serving network; a receiving module arranged to receive information of the dual-home separating path responded by the parent PCE, wherein the information of the dual-home separating path is computed by the parent PCE at least according to the information of the first dual-home path; and an establishment module arranged to establish a second dual-home path according to the information of the dual-home separating path. ### Claim 10 A device for establishing a multi-domain and dual-home path, located in a parent Path Computation Element PCE of a serving network, comprising: a receiving module arranged to receive information of a first dual-home path and a computation request of a dual-home separating path of the first dual-home path; a computation module arranged to respond to the computation request, and compute information of the dual-home separating path according to the information of the first dual-home path; and a sending module arranged to send the information of the dual-home separating path to a requester of the computation request, wherein the information of the dual-home separating path is used by the requester to establish a second dual-home path.