# US 2021/0176162 A1 · Methods and apparatus to reflect routes from a remotely located virtual route reflector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0176162 A1 - Document ID: US20210176162A1 - Status: Published application - Kind: A1 - Application number: 17/178,345 - Filed: 2021-02-18 - Published: 2021-06-10 - Earliest claimed: 2015-07-29 - Assignees: AT&T Intellectual Property I, L.P. - Applicants: AT&T Intellectual Property I, L.P. - Inventors: Chaitanya Yadlapalli; James Uttaro - Web page: https://patentgrep.com/patent/US20210176162A1 ## CPC - H04L 45/033: by updating distance vector protocols - H04L 45/04: {Interdomain routing, e.g. hierarchical routing} - H04L 45/12: Shortest path evaluation - H04L 45/52: Multiprotocol routers - H04L 45/586: of virtual routers - H04L 45/60: Router architectures - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Routes are reflected from a virtual route reflector. For instance, topology information and external route information are requested by a virtual route reflector remote from an autonomous system. The external route information identifies border routers through which a remote destination can be reached. Using the topology information, a first path can be selected from among paths emanating from a selected node in the autonomous system, the paths exiting the autonomous system at respective border routers of the border routers. Further, a route to the remote destination can be advertised from the virtual route reflector to a client router in the autonomous system, the route including a first border router at which the first path exits the autonomous system. ## Claims ### Claim 1 A method, comprising: based on information comprising a topology of a network within an autonomous system, selecting, by a virtual route reflector of a device comprising a processor, a lowest cost path from paths emanating from a selected internal node of internal nodes of the autonomous system and exiting the autonomous system at respective border routers at a border of the autonomous system that are able reach a destination node external to the autonomous system via an external network that is external to the network; and transmitting, by the virtual route reflector to a client router in the autonomous system, a route from the selected internal node to the destination node, the route comprising a border router of the respective border routers at which the lowest cost path exits the autonomous system. ### Claim 2 (depends on 1) The method of claim 1, wherein the lowest cost path is determined to be the border router having a nearest point of egress from the autonomous system relative to the selected internal node. ### Claim 3 (depends on 1) The method of claim 1, wherein the lowest cost path is determined to be the border router having a lowest overhead to send a packet between the selected internal node and the border router. ### Claim 4 (depends on 1) The method of claim 1, wherein the information further comprises external route information that identifies destination nodes that are able to be reached by the respective border routers of the autonomous system. ### Claim 5 (depends on 1) The method of claim 1, further comprising performing, by the virtual route reflector, the selecting and the transmitting for all of the internal nodes of the autonomous system. ### Claim 6 (depends on 1) The method of claim 1, further comprising performing, by the virtual route reflector, the selecting and the transmitting for the selected internal node to another destination node external to the autonomous system via the external network. ### Claim 7 (depends on 1) The method of claim 1, wherein the topology comprises respective costs for respective links of the topology. ### Claim 8 A server, comprising: a processor; and a memory that stores executable instructions that, when executed by the processor, facilitate performance of operations, comprising: selecting, using information comprising a topology of an internal network within an autonomous system, a lowest cost path from paths emanating from a selected node of nodes within the autonomous system and exiting the autonomous system at respective edge routers, at an edge of the autonomous system, that are able reach an external node outside of the autonomous system via an external network; and transmitting, to a client router within the autonomous system, a route from the selected node to the external node, the route comprising an edge router of the respective edge routers at which the lowest cost path exits the autonomous system. ### Claim 9 (depends on 8) The server of claim 8, wherein the lowest cost path is determined to be the edge router having a nearest exit point from the autonomous system relative to the selected node. ### Claim 10 (depends on 8) The server of claim 8, wherein the lowest cost path is determined to be the edge router having a lowest overhead to send a packet between the selected node and the edge router. ### Claim 11 (depends on 8) The server of claim 8, wherein the information further comprises external route information that identifies external nodes to which edge routers of the autonomous system are able to connect. ### Claim 12 (depends on 8) The server of claim 8, wherein the operations further comprise iteratively performing the selecting and the transmitting for the nodes of the autonomous system. ### Claim 13 (depends on 8) The server of claim 8, wherein the operations further comprise performing the selecting and the transmitting for the selected node to another external node outside of the autonomous system via the external network. ### Claim 14 (depends on 8) The server of claim 8, wherein the topology comprises respective costs for respective links specified by the topology. ### Claim 15 A non-transitory machine-readable medium, comprising executable instructions that, when executed by a processor of a device, facilitate performance of operations, comprising: selecting, using information comprising a topology of a network within an autonomous system, a lowest cost path from paths emanating from a selected node of nodes within the autonomous system and exiting the autonomous system at respective boundary routers at a boundary of the autonomous system that are able reach an external destination outside of the autonomous system via an external network; and transmitting, to a client router within the autonomous system, a route from the selected node to the external destination, the route comprising a boundary router of the respective boundary routers at which the lowest cost path exits the autonomous system. ### Claim 16 (depends on 15) The non-transitory machine-readable medium of claim 15, wherein the lowest cost path is determined to be the boundary router having a nearest exit point from the autonomous system relative to the selected node. ### Claim 17 (depends on 15) The non-transitory machine-readable medium of claim 15, wherein the lowest cost path is determined to be the boundary router determined to have a lowest overhead to send a packet between the selected node and the boundary router. ### Claim 18 (depends on 15) The non-transitory machine-readable medium of claim 15, wherein the information further comprises external route information that identifies external destinations that boundary routers of the autonomous system have been determined to be able to reach. ### Claim 19 (depends on 15) The non-transitory machine-readable medium of claim 15, wherein the operations further comprise iteratively performing the selecting and the transmitting for a defined group of the nodes of the autonomous system. ### Claim 20 (depends on 15) The non-transitory machine-readable medium of claim 15, wherein the operations further comprise performing the selecting and the transmitting for the selected node to another external destination outside of the autonomous system via the external network.