# US 12,009,984 B2 · Targeted neighbor discovery for border gateway protocol > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,009,984 B2 - Document ID: US12009984B2 - Status: Granted - Kind: B2 - Application number: 17/030,085 - Filed: 2020-09-23 - Published: 2022-03-24 - Granted: 2024-06-11 - Earliest claimed: 2020-09-23 - Assignees: Nokia Solutions and Networks Oy - Applicants: Nokia Solutions and Networks Oy - Inventors: Pranjal Kumar Dutta - Web page: https://patentgrep.com/patent/US12009984B2 ## CPC - H04L 45/04: {Interdomain routing, e.g. hierarchical routing} - H04L 45/26: {Route discovery packet} - H04L 67/141: Setup of application sessions (admission control or resource allocation in data switching networks H04L47/70) - H04L 12/66: Arrangements for connecting between networks having differing types of switching systems, e.g. gateways - H04L 41/40: using virtualisation of network functions or resources, e.g. SDN or NFV entities - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A first router receives a targeted message that is unicast from a second router that is multiple network hops away from the first router. The first router establishes a transport layer connection between the first router and the second router in response to the targeted message. The first router then establishes a session over the transport layer connection. The session operates according to a border gateway protocol (BGP). In some cases, the targeted message includes information such as an IP address of the first router, a transport layer parameter, an ASN associated with the second router, and an identifier of the routing protocol associated with the second router. A frequency of targeted messages exchanged by the first and second routers is reduced in response to a duration of the session increasing and turned off if the duration exceeds a threshold duration. ## Claims ### Claim 1 An apparatus, comprising: at least one processor; and at least one memory including instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving, at a first router from a second router that is multiple network hops away from the first router, a border gateway protocol hello message including an autonomous system number of the second router, a border gateway protocol identifier of the second router, and a set of flags, wherein the set of flags includes a first flag set to a value indicative that the border gateway protocol hello message is a state change hello message, a second flag set to a value indicative that the border gateway protocol hello message is a targeted border gateway protocol hello message, and a third flag set to a value indicative that the second router is requesting that the first router send periodic targeted border gateway protocol hello messages to the second router; establishing, by the first router based on the targeted border gateway protocol hello message, a border gateway protocol adjacency between the first router and the second router; establishing, by the first router based on the border gateway protocol adjacency, a transport layer connection between the first router and the second router; and establishing, by the first router based on the transport layer connection, a border gateway protocol session between the first router and the second router. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the targeted border gateway protocol hello message is received by the first router based on monitoring of an Internet Protocol (IP) address by the first router. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the targeted border gateway protocol hello message includes at least one of a transport layer parameter or an identifier of a routing protocol associated with the second router. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the first router is a route reflector router within an autonomous system (AS) that comprises the second router. ### Claim 5 An apparatus, comprising: at least one processor; and at least one memory including instructions that, when executed by the at least one processor, cause the apparatus at least to perform: sending, by a first router toward a second router that is multiple network hops away from the first router, a border gateway protocol hello message including an autonomous system number of the first router, a border gateway protocol identifier of the first router, and a set of flags, wherein the set of flags includes a first flag set to a value indicative that the border gateway protocol hello message is a state change hello message, a second flag set to a value indicative that the border gateway protocol hello message is a targeted border gateway protocol hello message, and a third flag set to a value indicative that the first router is requesting that the second router send periodic targeted border gateway protocol hello messages to the first router; establishing, by the first router based on the targeted border gateway protocol hello message, a border gateway protocol adjacency between the first router and the second router; establishing, by the first router based on the border gateway protocol adjacency, a transport layer connection between the first router and the second router; and establishing, by the first router based on the transport layer connection, a border gateway protocol session between the first router and the second router. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the targeted border gateway protocol hello message includes a border gateway protocol hello message. ### Claim 7 (depends on 5) The apparatus of claim 5, wherein the second router comprises a route reflector (RR). ### Claim 8 An apparatus, comprising: at least one processor; and at least one memory including instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving, at a first router from a second router, a targeted border gateway protocol hello message including a border gateway protocol identifier of the second router and an Internet Protocol address of the second router; determining, at the first router based on the border gateway protocol identifier of the second router, that the first router does not have a border gateway protocol adjacency with the second router; determining, at the first router, that the Internet Protocol address of the second router is included in a set of target Internet Protocol addresses configured on the first router; and establishing, by the first router based on the Internet Protocol address of the second router being included in the set of target Internet Protocol addresses configured on the first router, a targeted border gateway protocol adjacency with the second router based on the border gateway protocol identifier of the second router.