Hardware based fast convergence for network failures
AssigneeCisco Technology, Inc.
InventorsNavindra Yadav, Ayaskant Pani, Kit Chiu Chu
Life of this patent
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Abstract
Certain features required for routing decisions are provided by hardware. For example, the router logic may be modified to provide multiple alternative paths for a link. In some implementations, hardware autonomously detects a link or port failure and routes on an alternate link without software intervention. In one approach, the router stores the alternate paths in the data plane. In some implementations, network devices are also configured for active loop avoidance and detection is implemented so that packets never loop due to multiple failures that occur close to each other.
Claims44
A network device comprising:
- (a) a plurality of interfaces for coupling with network links;
- and
- (b) a processor with hardware logic configured to
- determine that a link to one of the plurality of interfaces of the network device is not functioning properly,
- look up, in a forwarding table, interfaces of the network device for reaching network addresses, the forwarding table containing, for each of one or more network addresses, a primary interface of the plurality of interfaces and one or more alternate interfaces of the plurality of interfaces, and
- upon determining that the primary interface of the network device for reaching a network address is coupled to the link identified as not functioning properly, identify, in the forwarding table, one of the alternate interfaces for reaching the network address.
A network comprising a plurality of leaf and spine network devices connected in a multi-rooted tree topology,
- wherein each of at least some of the spine network devices comprises:
- a plurality of interfaces for coupling with network links;
- and
- a processor with hardware logic configured to
- determine that a link to one of the plurality of interfaces is not functioning properly,
- look up, in a forwarding table, interfaces for reaching network addresses, the forwarding table containing, for each of one or more network addresses, a primary interface of the plurality of interfaces and one or more alternate interfaces of the plurality of interfaces, and
- identify in the forwarding table, one of the alternate interfaces for reaching a network address after the primary interface for said network address coupled to the link is identified as not functioning properly;
- and
- wherein each of the leaf network devices comprise:
- a plurality of interfaces for coupling with spine network devices and end devices.
A method of rerouting a packet when a link to a network device has failed, the network device comprising a plurality of interfaces for coupling with network links, and a processor with hardware logic, the method comprising:
- (a) determining, by the network device, that a link to one of the plurality of interfaces of the network device is not functioning properly,
- (b) looking up interfaces for reaching network addresses in a forwarding table containing, for each of one or more network addresses, a primary interface of the plurality of interfaces and one or more alternate interfaces of the plurality of interfaces, and
- (c) identifying in the forwarding table one of the alternate interfaces for reaching a network address upon determining that the primary interface for said network address is coupled to the link identified as not functioning properly,
- wherein at least (b) and (c) are performed by the hardware logic.
Dependencies are inferred from the claim text.