# US 2021/0243044 A1 · Re-convergence of protocol independent multicast assert states > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0243044 A1 - Document ID: US20210243044A1 - Status: Published application - Kind: A1 - Application number: 16/778,669 - Filed: 2020-01-31 - Published: 2021-08-05 - Earliest claimed: 2020-01-31 - Assignees: Cisco Technology, Inc. - Applicants: Cisco Technology, Inc. - Inventors: Ramakrishnan Chokkanathapuram Sundaram; Kesavan Thiruvenkatasamy; Rishabh Parekh; Raunak Banthia - Web page: https://patentgrep.com/patent/US20210243044A1 ## CPC - H04L 45/16: Multipoint routing - H04L 12/185: {with management of multicast group membership} - H04L 45/02: Topology update or discovery - H04L 45/021: Ensuring consistency of routing table updates, e.g. by using epoch numbers - H04L 49/201: Multicast operation; Broadcast operation - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract This disclosure describes techniques for improving convergence of Protocol Independent Multicast assert state information in multicast groups. A method includes forwarding, by a router, a PIM join message originating from a destination host and stores distribution tree information based on the join message. The method further includes participating, by the router, in a Protocol Independent Multicast (“PIM”) assert election among a plurality of routers and storing, by the router, PIM assert state information based on an outcome of the PIM assert election. The method further includes acquiring, by the router, routing information base (“RIB”) convergence. The method further includes triggering by the router, or causing, by the router, another router to trigger, a PIM assert among the plurality of routers. The method further includes re-converging, by the router, with PIM assert states among the plurality of routers and storing, by the router, converged PIM assert state information. ## Claims ### Claim 1 A router comprising: one or more processors; and one or more non-transitory computer-readable media storing computer-executable instructions that, when executed by the one or more processors, cause the one or more processors to: participate in a Protocol Independent Multicast (“PIM”) assert election among a plurality of routers and store PIM assert state information based on an outcome of the PIM assert election; acquire routing information base (“RIB”) convergence; trigger, or cause another router to trigger, a PIM assert among the plurality of routers; and re-converge with PIM assert states among the plurality of routers and store converged PIM assert state information. ### Claim 2 (depends on 1) The router of claim 1, wherein the instructions further cause the one or more processors to store PIM assert state information based on the outcome of the router being elected as a PIM assert winner in the PIM assert election. ### Claim 3 (depends on 1) The router of claim 1, wherein the instructions cause the one or more processors to acquire RIB convergence following a convergence-loss event at the router, and the instructions cause the PIM assert to be triggered before or after RIB convergence is acquired. ### Claim 4 (depends on 1) The router of claim 1, wherein a Generation ID (“GenID”) of the router changes after the one more processors acquire RIB convergence, and causing another router to trigger the PIM assert comprises forwarding a PIM message among the plurality of routers. ### Claim 5 (depends on 4) The router of claim 4, wherein the instructions further cause the one or more processors to participate in a second PIM assert election among the plurality of routers and store PIM assert state information based on an outcome of the second PIM assert election. ### Claim 6 (depends on 1) The router of claim 1, wherein a GenID of the router remains the same after the one or more processors acquire RIB convergence, and triggering the PIM assert comprises sending a PIM hello message including an assert state request option to the plurality of routers. ### Claim 7 (depends on 6) The router of claim 6, wherein the instructions further cause the one or more processors to receive a join message including a PIM assert re-trigger option, and re-converging with PIM assert states comprises sending a PIM assert message to the plurality of routers. ### Claim 8 A method comprising: participating, by a router, in a Protocol Independent Multicast (“PIM”) assert election among a plurality of routers and storing, by the router, PIM assert state information based on an outcome of the PIM assert election; acquiring, by the router, routing information base (“RIB”) convergence; triggering by the router, or causing, by the router, another router to trigger, a PIM assert among the plurality of routers; and re-converging, by the router, with PIM assert states among the plurality of routers and storing, by the router, converged PIM assert state information. ### Claim 9 (depends on 8) The method of claim 8, wherein PIM assert state information is stored based on the outcome of the router being elected as a PIM assert winner in the PIM assert election. ### Claim 10 (depends on 8) The method of claim 8, wherein RIB convergence is acquired following a convergence-loss event at the router, and the PIM assert is triggered before or after RIB convergence is acquired. ### Claim 11 (depends on 8) The method of claim 8, wherein a Generation ID (“GenID”) of the router changes after acquiring, by the router, RIB convergence, and causing, by the router, another router to trigger the PIM assert comprises forwarding, by the router, a PIM message among the plurality of routers. ### Claim 12 (depends on 11) The method of claim 11, further comprising participating, by the router, in a second PIM assert election among the plurality of routers and storing, by the router, PIM assert state information based on an outcome of the second PIM assert election. ### Claim 13 (depends on 8) The method of claim 8, wherein a GenID of the router remains the same after acquiring, by the router, RIB convergence, and triggering, by the router, the PIM assert comprises sending, by the router, a PIM hello message including an assert state request option to the plurality of routers. ### Claim 14 (depends on 13) The method of claim 13, further comprising receiving, by the router, a join message including a PIM assert re-trigger option, and re-converging, by the router, with PIM assert states comprises sending, by the router, a PIM assert message to the plurality of routers. ### Claim 15 A router comprising: one or more processors; and one or more non-transitory computer-readable media storing computer-executable instructions that, when executed by the one or more processors, cause the one or more processors to: participate in a Protocol Independent Multicast (“PIM”) assert election among a plurality of routers and store PIM assert state information based on an outcome of the PIM assert election; acquire routing information base (“RIB”) convergence; send a hello message including a state request option to the plurality of routers; and re-converge with PIM assert states among the plurality of routers and store converged PIM assert state information. ### Claim 16 (depends on 15) The router of claim 15, wherein the instructions further cause the one or more processors to store PIM assert state information based on the outcome of the router being elected as a PIM assert loser in the PIM assert election. ### Claim 17 (depends on 15) The router of claim 15, wherein the instructions cause the one or more processors to acquire RIB convergence following a convergence-loss event at the router, and the instructions cause the hello message to be sent before or after RIB convergence is acquired. ### Claim 18 (depends on 15) The router of claim 15, wherein the one or more processors is configured to send the hello message including a state request option is performed after the router has acquired RIB convergence. ### Claim 19 (depends on 15) The router of claim 15, wherein re-converging with PIM assert states comprises receiving a PIM assert message from a PIM assert winner. ### Claim 20 (depends on 19) The router of claim 19, wherein re-converging with PIM assert states comprises storing PIM assert state information based on the PIM assert message.