In-service software upgrade utilizing metadata-driven state translation

Abstract

A method and apparatus for a metadata-driven upgrade of a network element is described. A network element comprises an active and backup controller card and receives new software to be installed on that network element. In addition, the network element installs the software on the backup controller card and synchronizes the active state of the network element to the backup controller card. Furthermore, the network element uses metadata to translate the active state to the format used by the new software.

What is claimed is: 
     
         1 . A method performed within a network element having a first controller card and a second controller card, the method comprising:
 receiving new software to be installed on the network element, wherein the first controller card is currently acting as an active controller card and is running old software that uses a first data structure format, wherein the new software comprises second metadata describing a second data structure format used by the new software, wherein the first data structure format is not the same as the second data structure format;   installing the new software on the second controller card, wherein the second controller card is currently acting as a backup controller card;   synchronizing, from the first controller card onto the second controller card, active state data representing an active state of the network element, wherein the active state data is stored in the first data structure format; and   translating the active state data synchronized onto the second controller card from the first data structure format into the second data structure format using the second metadata, wherein the active state data that is translated using the second metadata includes at least one of a traffic forwarding table, user session information, and subscriber session information, wherein the active state data that is translated has been dynamically built up during runtime and is used to control how the network element handles data traffic.   
     
     
         2 . The method of  claim 1 , wherein the new software is one of a network element operating system and a service running on the network element. 
     
     
         3 . The method of  claim 1 , wherein a first metadata describes constituent fields of the first data structure format used by the old software including names, types, and sizes of the constituent fields, and wherein translating comprises comparing the second metadata describing the second data structure format used by the new software with the first metadata associated with the old software. 
     
     
         4 . The method of  claim 1 , further comprising switching control from the first controller card over to the second controller card so that the second controller card begins to act as the active controller card, wherein the second controller card is running the new software. 
     
     
         5 . The method of  claim 1 , wherein the translating also includes one or more of adding a field to the first data structure format, removing a field from the first data structure format, rearranging two or more fields in the first data structure format, and changing a literal value associated with an enumerated constant. 
     
     
         6 . The method of  claim 1 , further comprising assigning a default value to a field of the second data structure format, wherein there is no corresponding field in the first data structure format. 
     
     
         7 . A machine-readable storage medium that stores instructions, which when executed by a set of one or more processors, causes said set of one or more processors to:
 responsive to receiving new software, install the new software on a second controller card, which is currently acting as a backup controller card, while a first controller card, which is currently acting as an active controller card, runs old software that uses a first data structure format, wherein the new software comprises second metadata that describes a second data structure format used by the new software, wherein the first data structure format is not the same as the second data structure format;   synchronize active state data that represents an active state of a network element, from the first controller card onto the second controller card , wherein the active state data is stored in the first data structure format; and   translate the active state data synchronized onto the second controller card from the first data structure format into the second data structure format using the second metadata, wherein the active state data to be translated using the second metadata includes at least one of a traffic forwarding table, user session information, and subscriber session information, wherein the active state data to be translated is dynamically built up during runtime and is used to control how the network element handles data traffic.   
     
     
         8 . The machine-readable storage medium of  claim 7 , wherein the new software is one of a network element operating system and a service that runs on the network element. 
     
     
         9 . The machine-readable storage medium of  claim 7 , wherein a first metadata describes constituent fields of the first data structure format used by the old software including names, types, and sizes of the constituent fields, and wherein the translation of the active state comprises a comparison of the second metadata that describes the second data structure format used by the new software with the first metadata associated with the old software. 
     
     
         10 . The machine-readable storage medium of  claim 7 , wherein the instructions further cause the set of one or more processors to:
 switch control from the first controller card over to the second controller card so that the second controller card begins to act as the active controller card, wherein the second controller card runs the new software.   
     
     
         11 . The machine-readable storage medium of  claim 7 , wherein the translation of the active state includes an operation to change the byte offset of a field within the second data structure format from the byte offset of the corresponding field within the first data structure format. 
     
     
         12 . The machine-readable storage medium of  claim 7 , wherein the translation of the active state also includes one or more of addition of a field to the first data structure format, removal of a field from the first data structure format, rearrangement of two or more fields in the first data structure format, and change of a literal value associated with an enumerated constant. 
     
     
         13 . The machine-readable storage medium of  claim 7 , wherein the instructions further cause the set of one or more processors to:
 assign a default value to a field of the second data structure format, wherein there is no corresponding field in the first data structure format.   
     
     
         14 . A network element comprising:
 a first controller card and a second controller card;   a machine-readable storage medium storing instructions, which when executed by a processor of the network element, cause said network element to:   responsive to receiving new software, install the new software on the second controller card, which is currently acting as a backup controller card, while the first controller card, which is currently acting as an active controller card, runs old software that uses a first data structure format, wherein the new software comprises second metadata that describes a second data structure format used by the new software, wherein the first data structure format is not the same as the second data structure format;   synchronize, from the first controller card onto the second controller card, active state data that represents an active state of the network element, wherein the active state data is stored in the first data structure format; and   translate the active state data synchronized onto the second controller card from the first data structure format into the second data structure format using the second metadata, wherein the active state data that is translated using the second metadata includes at least one of a traffic forwarding table, user session information, and subscriber session information, wherein the active state data that is translated has been dynamically built up during runtime and is used to control how the network element handles data traffic.   
     
     
         15 . The network element of  claim 14 , wherein a first metadata describes constituent fields of the first data structure format used by the old software including names, types, and sizes of the constituent fields, and wherein the translation of the active state comprises a comparison of the second metadata that describes the second data structure format used by the new software with the first metadata associated with the old software. 
     
     
         16 . The network element of  claim 14 , wherein the network element is operative to switch control from the first controller card over to the second controller card so that the second controller card begins to act as the active controller card, wherein the second controller card runs the new software. 
     
     
         17 . The network element of  claim 14 , wherein the new software is one of a network element operating system and a service that runs on the network element, and wherein the active state that is to be translated includes a traffic forwarding table. 
     
     
         18 . The network element of  claim 14 , wherein the translation of the active state includes an operation to change the byte offset of a field within the second data structure format from the byte offset of the corresponding field within the first data structure format. 
     
     
         19 . The network element of  claim 14 , wherein the translation of the active state also includes one or more of addition of a field to the first data structure format, removal of a field from the first data structure format, rearrangement of two or more fields in the first data structure format, and change of a literal value associated with an enumerated constant. 
     
     
         20 . The network element of  claim 14 , wherein the instructions further cause the network element to:
 assign a default value to a field of the second data structure format, wherein there is no corresponding field in the first data structure format.