Method and Apparatus for Restoring Service Label Information

Abstract

Multiple service label types may be used in a given network element to optimize scalability of the data plane, minimize overhead associated with service label management, and allow new services to be offered. Service label management may be done in a dynamic manner so that service labels may be selected for routes in a dynamic fashion as the network changes. VPNs handled by the network element may have different types of service labels, and different routes within a particular VPN may be allocated different service label types. Service label requests may be stored on the data plane to allow a service label request database to be restored from the data plane upon a control plane failure, so that new service labels are not required to be allocated after a control plane failure.

1 - 16 . (canceled) 
     
     
         17 . A method of enabling recovery of service label information after a control plane failure in routed data network, the method comprising:
 storing, in a data plane of the routed data network, information characterizing requests for service labels; and   storing, in the data plane in association with the stored information characterizing requests for service labels, information indicative of service labels allocated in response to the service label requests.   
     
     
         18 . The method of  claim 17 , further comprising providing, from the data plane to the control plane on loss of data by the control plane, at least some of the stored information characterizing requests for service labels and at least some of the associated stored information indicative of service labels allocated in response to the service label requests. 
     
     
         19 . The method of  claim 18 , wherein:
 storing information in the data plane comprises storing information in at least one line card of a network element; and   providing information from the data plane to the control plane comprises providing information from the at least one line card to at least one control card of the network element.   
     
     
         20 . The method of  claim 19 , wherein the at least one control card is configured to maintain a label database. 
     
     
         21 . The method of  claim 20 , wherein the at least one control card is configured to repopulate the label database after loss of data from the label database using information characterizing requests for service labels and information indicative of service labels allocated in response to the service label requests provided by the at least one data card. 
     
     
         22 . The method of  claim 21 , wherein the at least one control card comprises a label manager configured:
 to match a new service label request with a service label request characterized in the repopulated label database; and   in response to the matched new service label request, to assign a service label associated with the service label request characterized in the repopulated label database.   
     
     
         23 . The method of  claim 22 , wherein the label manager is configured to assign a service label not currently in use on the network when a new service label request does not match any service label request characterized in the repopulated label database. 
     
     
         24 . The method of  claim 17 , wherein the information characterizing requests for service labels is not used by the data plane to program the data plan to handle data traffic. 
     
     
         25 . The method of  claim 17 , wherein:
 the routed data network is a Multi-Protocol Label Switching (MPLS) based Virtual Private Network (VPN); and   the service labels are inner labels used to identify traffic received from a label switched paths.   
     
     
         26 . The method of  claim 25 , wherein the MPLS VPN uses outer transport labels to switch traffic along the label switched paths. 
     
     
         27 . The method of  claim 17 , further comprising advertising a route with an associated service label. 
     
     
         28 . The method of  claim 17 , wherein each service label has a service label type attribute specifying data plane actions to be taken on packets associated with the service label. 
     
     
         29 . The method of  claim 28 , wherein different service label type attributes specify different data plane actions to be taken on packets associated with the service label.