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US 9,178,797 B2Granted
Selective BGP graceful restart in redundant router deployments
AssigneeJuniper Networks, Inc.
InventorsJohn Galen Scudder, Ross W. Callon
Life of this patent
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AssigneeJuniper Networks, Inc.
InventorsJohn Galen Scudder, Ross W. Callon
Estimating the term…
In general, techniques are described for selectively invoking graceful restart procedures when a route reflector member of a redundant route cluster fails. In one example, a method is provided that includes determining, by a provider edge router that supports graceful restart procedures, that a first router forms a redundant group with at least a second router. The method also includes detecting a failure of the first router and determining that at least the second router in the redundant group is operating approximately while the first router is failed. The method further includes overriding graceful restart procedures with respect to the failed first router when at least the second router is operating. The method also includes forwarding one or more data packets according to route information provided via the second router.
A method, comprising:
A graceful restart enabled network device, comprising:
A tangible non-transitory computer-readable medium comprising instructions for causing a programmable processor to perform operations comprising:
A method comprising:
Dependencies are inferred from the claim text.
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Topology update or discovery: ensuring consistency of routing table updates, e.g. by using epoch numbers
By isolating or reconfiguring faulty entities: by reconfiguring faulty entities
Using network fault recovery: by dynamic selection of recovery network elements, e.g. replacement by the most appropriate element after failure
Topology update or discovery: delayed use of routing table updates
About 6 years 8 months of term left · ends 28 Jun 2033 (estimated)
The invention relates to computer networks and, more specifically, to techniques to reduce a recovery period in the event a network device incurs a failure.
A computer network is a collection of interconnected computing devices that exchange data and share resources. In a packet-based network, such as the Internet, computing devices communicate data by dividing the data into small blocks called packets, which are individually routed across the network from a source device to a destination device. The destination device extracts the data from the packets and assembles the data into its original form. Dividing the data into packets enables the source device to resend only those individual packets that may be lost during transmission.
Certain devices within the network, such as routers, maintain routing information that describes routes through the network. Each route defines a path between two locations on the network. From the routing information, the routers may generate forwarding information, which is used by the routers to relay packet flows through the network and, more particularly, to relay the packet flows to a next hop. In reference to forwarding a packet, the “next hop” from a network router typically refers to a downstream neighboring device along a given route. Upon receiving an incoming packet, the router examines information within the packet to identify the destination for the packet. Based on the destination, the router forwards the packet in accordance with the forwarding information.
FIG. 1 is a block diagram illustrating an example computer network in which some network devices form a redundant route reflector cluster, in accordance with techniques described herein.
FIG. 2 is a block diagram illustrating one exemplary embodiment of a provider edge (PE) router that forwards data packets according to redundant routes in redundant route reflector cluster when a communication session with a router of the cluster is down, in accordance with techniques described herein.
FIGS. 3A and 3B are block diagrams illustrating example forwarding procedures based on a position of a failed router in the network topology, in accordance with techniques described herein.
In accordance with common practice, the various described features are not drawn to scale and are drawn to emphasize features relevant to the present invention. Like reference characters denote like elements throughout the figures and text.
FIG. 1 is a block diagram illustrating an example communication network 2 in which some network devices selectively invoke graceful restart in accordance with the techniques described herein. In the example of FIG. 1, communication network 2 includes an intermediate network 6, such as a service provider network, that interconnects computer networks 8-1 through 8-L, collectively referred to as “computer networks 8.” Designator L may be any number of computer networks 8 that communication network 2 supports. Computer networks 8 are communicatively connected to at least one provider edge router 4 of network 6. FIG. 1 is just one example of a communication network 2 and is not meant to be limiting.
In the example of FIG. 1, network 6 includes provider edge (PE) routers 4-1 through 4-N, collectively referred to as “provider edge routers 4.” A provider edge router 4 may refer to any router coupled to a route cluster. That is, a provider edge router 4 may be any type of router that is a client router of a redundant route reflector cluster. Network 6 also includes core routers 10-1 and 10-2, collectively referred to as “routers 10.” Each router 4 and 10 is connected to at least one other router 4 or 10 through one or more data links 16 through 16 (referred to collectively as “data links 16”). Provider edge router 4-1 which serves as an ingress point (and, in some cases, an egress point) between computing network 8-1 and network 6. Network 6 also comprises provider edge routers 4-2 through 4-N that function as ingress or egress points. For illustrative purposes only, FIG. 1 depicts network 6 as comprising four provider edge routers, PEs 4-1 through 4-N. In other examples, network 6 comprises other numbers of provider routers 4, including multiple ingress and egress routers.