US 11,882,019 B1
Source address validation for asymmetric routing
Alfred Clarence Lindem, III, Cary, NC (US); Peter Psenak, Bratislava (SK); and Lester C Ginsberg, Mount Hermon, CA (US)
Assigned to CISCO TECHNOLOGY, INC., San Jose, CA (US)
Filed by Cisco Technology, Inc., San Jose, CA (US)
Filed on Dec. 30, 2022, as Appl. No. 18/091,824.
Claims priority of provisional application 63/391,663, filed on Jul. 22, 2022.
Int. Cl. H04L 45/02 (2022.01); H04L 45/122 (2022.01); H04L 45/00 (2022.01)
CPC H04L 45/122 (2013.01) [H04L 45/02 (2013.01); H04L 45/20 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method performed by a network switching device connected with a computer network, the method comprising:
receiving by the network switching device, network topology information from a node of the network;
updating a link-state database of the network switching device based on the network topology information;
receiving a data packet associated with a data flow between one or more nodes of the computer network and the network switching device;
determining whether the data packet was received from a reverse path forwarding interface;
in response to determining that the data packet was received from a reverse path forwarding interface, sending the data packet from the network switching device to a next-hop node of the computer network;
in response to determining that the data packet was not received from a reverse path forwarding interface performing a shortest path first calculation rooted at a router advertising a source network of the data packet;
determining whether the data packet was received from a valid path of the computer network based on the shortest path first calculation;
in response to determining that the data packet was received from a valid path, sending the data packet from the network switching device to the next-hop node of the computer network; and
in response to determining that the data packet was not received from a valid path of the computer network, dropping the data packet.