Efficient convergence of grouped VPN prefixes

摘要

In one embodiment, a list of border node next hop options is maintained in a memory. The list of border node next hop options includes one or more of border nodes that may be utilized to reach one or more prefixes. An index value is associated with each border node of the list of border node next hop options. A list of labels is also maintained in the memory. The index value of each border node is associated with a corresponding label for a path to reach that border node. When a change to the one or more border nodes is detected, the list of border node next hop options is updated to remove a border node. However, a label for the path to reach the border node is maintained in the list of labels for at least a period of time.

主权项

1. A method comprising:
maintaining a list of border node next hop options in a memory of a network device, the list of border node next hop options including one or more border nodes that may be utilized to reach one or more prefixes; maintaining a list of virtual private network (VPN) labels in the memory of the network device, the list of VPN labels including one or more labels for paths; determining that one or more prefixes share the one or more border nodes from the list of border node next hop options; associating an index value with each shared border node; associating the index value of each shared border node of the list of border node next hop options with a corresponding VPN label of the list of VPN labels for a path to reach that border node; receiving traffic associated with a prefix of the one or more prefixes; determining, using the prefix, a particular border node for the traffic from the one or more shared border nodes; determining the index value based on the particular border node; applying the index value to select a VPN label from the list of VPN labels; applying the selected VPN label to the traffic; detecting a change to the one or more shared border nodes that may be utilized to reach the prefix; in response to the detecting, updating the list of border node next hop options to remove a border node from the list of border node next hop options, while maintaining a VPN label for the path to reach the border node in the list of VPN labels for at least a period of time; forwarding, by the network device, the traffic associated with the prefix by determining a second particular border node for the traffic from the one or more shared border nodes, determining a second index value associated with the second particular border node and applying the second index value to the list of VPN labels to determine a particular VPN label for the traffic.