US 12,149,432 B2
Source address validation for asymmetric routing
Alfred Clarence Lindem, III, Cary, NC (US); Lester C Ginsberg, Mount Hermon, CA (US); and Peter Psenak, Bratislava (SK)
Assigned to Cisco Technology, Inc., San Jose, CA (US)
Filed by Cisco Technology, Inc., San Jose, CA (US)
Filed on Nov. 3, 2023, as Appl. No. 18/501,775.
Application 18/501,775 is a continuation of application No. 18/091,824, filed on Dec. 30, 2022, granted, now 11,882,019.
Claims priority of provisional application 63/391,663, filed on Jul. 22, 2022.
Prior Publication US 2024/0064092 A1, Feb. 22, 2024
Int. Cl. H04L 45/122 (2022.01); H04L 45/00 (2022.01); H04L 45/02 (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 device connected to a network, the method comprising:
receiving a packet from a destination node, the packet being destined for a source node and sent via a return network path in the network;
determining that the packet was received on an interface that is a non-Reverse Path Forwarding (non-RPF) interface for the source node;
performing a path computation to determine one or more network devices in one or more network paths between the network device and the source node;
determining that one or more interfaces associated with the one or more network devices are valid RPF interfaces for the source node;
determining whether the interface is included in the valid RPF interfaces for the source node; and
in response to determining that the interface is included in the valid RPF interfaces, forwarding the packet to a next-hop node; or
in response to determining that the interface is not included in the valid RPF interfaces, dropping the packet.