MANAGING ROUTING INFORMATION IN A HUB-AND-SPOKES NETWORK

摘要

In general, techniques are described for managing routing information in a hub-and-spoke network 2 in a manner that reduces flooding of link information. A hub router 6 of a virtual private network (VPN) 2, configured in a hub-and-spoke network topology, including a memory and a processor performs the techniques. The memory is configured to store a representation of a topology of the VPN 2. The processor is configured to utilize a separate instance of a multi-instance version of a link state protocol to communicate with each of a plurality of spoke routers 10A, 10B of the VPN 2. Each separate instance of the multi-instance version of the link state protocol includes the hub router 6 and a different one of the plurality of spoke routers10A, 10B. The processor processes link state advertisements from the separate instances of the multi-instance version of the link state protocol to maintain the representation of the topology of the VPN 2. VPN 2 includes spoke site networks 12A to 12C connected to a public network 4. Each of spoke site networks 12A to 12C is connected to spoke site routers 10A and 10B via one or more access links 11. Routers 6, 10A, 10B exchange link information with one another in accordance with a multi-instance form of a link state protocol, such as Open Shortest Path First (OSPF) or an Intermediate System-to-Intermediate System (IS-IS). OSPF routing instances 14A, 14B correspond to different interior gateway protocol (IGP) routing domains. Each one of instances 14A, 14B is configured to include hub router 6 and a different one of spoke routers 10. Because each one of instances 14A, 14B of the multi-instance OSPF protocol is separate from one another, spoke routers 10A, 10B may only flood link state advertisements to hub router 6 and not to those of spoke routers 10A, 10B participating in separate OSPF instances 14. In this respect, the number of link state advertisements flooded between spoke routers 10A, 10B is reduced and potentially eliminated.