LAYER 3 ROUTING LOOP PREVENTION SYSTEM

摘要

A layer 3 routing loop prevention system includes a port extender coupled to a first and second control bridges by a LAG. The first and second control bridges are coupled by an interchassis link. When the first control bridge receives a packet and determines that its LAG link to the port extender is unavailable, it provides a control bridge failover identifier in the packet and performs layer 3 forwarding to send the packet to the second control bridge over the interchassis link. When the second control bridge receives the packet though the interchassis link and determines that its LAG link to the port extender is unavailable, that the packet includes the first control bridge failover identifier, and that layer 3 forwarding will result in the packet being sent back to the first control bridge device, the packet is dropped to prevent layer 3 routing loops.

主权项

1. A layer 3 routing loop prevention system, comprising:
an extender device; a first control bridge device that is coupled to the extender device by at least one first link in a first link aggregation group (LAG); a second control bridge device that is coupled to the extender device by at least one second link in the first LAG, to the first control bridge device by at least one third link, and to a network, wherein the second control bridge is configured to:
receive a packet through the network that is directed to the extender device;determine that the at least one second link is unavailable for forwarding the packet to the extender device;provide a second control bridge device failover identifier in the packet; andperform layer 3 forwarding to send the packet to the first control bridge device over the at least one third link; wherein the first control bridge device is configured to:
receive the packet from the second control bridge device over the at least one third link;determine that the at least one first link is unavailable for forwarding the packet to the extender device;determine that the performance of layer 3 forwarding will result in the packet being sent to the second control bridge device; anddrop the packet in response to determining that the packet was received from the second control bridge device over the at least one third link, includes the second control bridge device failover identifier, and will be sent to the second control bridge device if layer 3 forwarding is performed.