Systems for supporting packet processing operations
Several systems for supporting packet processing are described. A first system supports virtual routing of a packet. A second system supports de-multiplexing of a packet. A third system supports advanced MPLS label processing of a packet.
1. A system comprising:
a receive interface to receive a packet comprising at least a destination address, a payload, and a key indicating a desired class of service for the packet selected from a plurality of possible classes of service;
key deriving logic for deriving the key indicating the desired class of service for the packet from the plurality of possible classes of service selected from the group comprising uni-cast routing, multi-cast routing, and bridging;
starting address logic for providing a starting address of a program sequence for processing the packet responsive to the key, the starting address selected from a plurality of possible starting addresses, each associated with a different class of service from among the plurality of possible classes of service, wherein the starting address logic is a content addressable memory (CAM) holding a plurality of entries, each having a tag portion and a content portion indicating the starting address of a program sequence for a desired class of service, wherein the CAM is configured to search for an entry having a tag portion matching the key and a content portion indicating the starting address for a program sequence corresponding to the desired class of service indicated by the key, and, when a match is found, outputting the content portion of the matching entry and a signal indicating a hit condition, and, when a match is not found, outputting a signal indicating a miss condition;
a memory for holding a plurality of program sequences corresponding to the possible starting addresses; and
execution logic for executing the program sequence corresponding to the starting address provided by the starting address logic.
2. The system of claim 1 wherein the starting address logic is a lookup table holding a plurality of addressable entries, each indicating the starting address of a program sequence for a desired class of service, wherein the lookup table is configured to access an entry in the table addressed by the key and indicating the starting address for a program sequence corresponding to the desired class of service indicated by the key, and output the starting address indicated by the entry.
3. A method comprising:
receiving a packet comprising at least a destination address, a payload, and a key indicating a desired class of service for the packet selected from a plurality of possible classes of service;
deriving a key indicating the desired class of service for the packet from the plurality of possible classes of service selected from the group comprising uni-cast routing, multi-cast routing, and bridging;
providing a starting address of a program sequence for the packet responsive to the key, the starting address selected from a plurality of possible starting addresses, each associated with a different class of service from among the plurality of possible classes of service, wherein providing the starting address of the program sequence comprises searching through a plurality of entries, each having a tag portion and a content portion indicating the starting address of a program sequence for a desired class of service, for an entry having a tag portion matching the key and a content portion indicating the starting address for a program sequence corresponding to the desired class of service indicated by the key, and, if a match is found, outputting the content portion of the matching entry and a signal indicating a hit condition, and, if a match is not found, outputting a signal indicating a miss condition;
holding a plurality of program sequences corresponding to the plurality of possible starting addresses; and
executing the program sequence corresponding to the provided starting address.
4. The method of claim 3 wherein providing the starting address of the program sequence comprises addressing a plurality of addressable entries, each indicating the starting address of a program sequence for a desired class of service, to access an entry addressed by the key and indicating the starting address for a program sequence corresponding to the desired class of service indicated by the key, and outputting the starting address indicated by the addressed entry.
5. A packet processing system comprising:
a memory to store logic;
a Content Addressable Memory (CAM) to store a plurality of program sequences;
a processor to execute the logic and one or more of the plurality of the program sequences;
a receive interface to receive a packet comprising at least a destination address, a payload, and a key indicating a desired class of service for the packet selected from a plurality of possible classes of service;
wherein the logic comprises:
key deriving logic to derive the key indicating the desired class of service for the packet from the plurality of possible classes of service;
searching logic to search a plurality of entries, each having a tag portion and a content portion, for an entry having a tag portion that matches the key, the searching logic to further output the content portion of a matching entry and an indicator of a hit condition when the matching entry is found, and output an indicator of a miss condition when the matching entry is not found;
starting address logic to provide a starting address of one of the plurality of program sequence in the CAM for processing the packet responsive to the key, the starting address selected from a plurality of possible starting addresses, each associated with a different class of service from among the plurality of possible classes of service; and
execution logic for executing the program sequence corresponding to the starting address provided by the starting address logic.
6. The packet processing system of claim 5 wherein the processing logic is to execute a programmed sequence of one or more commands for the packet, including executing a first command if the searching logic outputs an indicator of a hit condition, and second command distinct from the first if the searching logic outputs an indicator of a miss condition.
7. A non-transitory processor-readable medium having instructions stored thereon that, when executed by a processor in a packet processing system, the instructions cause the packet processing system to perform operations comprising:
receiving a packet comprising at least a destination address, a payload, and a key indicating a desired class of service for the packet selected from a plurality of possible classes of service;
deriving a key indicating the desired class of service for the packet from the plurality of possible classes of service selected from the group comprising uni-cast routing, multi-cast routing, and bridging;
providing a starting address of a program sequence for the packet responsive to the key, the starting address selected from a plurality of possible starting addresses, each associated with a different class of service from among the plurality of possible classes of service;
wherein providing the starting address of the program sequence comprises searching through a plurality of entries, each having a tag portion and a content portion indicating the starting address of a program sequence for a desired class of service, for an entry having a tag portion matching the key and a content portion indicating the starting address for a program sequence corresponding to the desired class of service indicated by the key, and, if a match is found, outputting the content portion of the matching entry and a signal indicating a hit condition, and, if a match is not found, outputting a signal indicating a miss condition;
holding, in a Content Addressable Memory (CAM) of the packet processing system, a plurality of program sequences corresponding to the plurality of possible starting addresses; and
executing the program sequence corresponding to the provided starting address.
8. The non-transitory processor-readable medium of claim 7 wherein providing the starting address of the program sequence comprises addressing a plurality of addressable entries in the CAM, each indicating the starting address of a program sequence for a desired class of service, to access an entry addressed by the key and indicating the starting address for a program sequence corresponding to the desired class of service indicated by the key, and outputting the starting address indicated by the addressed entry.
9. A packet processing system comprising:
means for receiving a packet comprising at least a destination address, a payload, and a key indicating a desired class of service for the packet selected from a plurality of possible classes of service selected from the group comprising uni-cast routing, multi-cast routing, and bridging;
means for deriving a key indicating the desired class of service for the packet from the plurality of possible classes of service;
means for providing a starting address of a program sequence for the packet responsive to the key, the starting address selected from a plurality of possible starting addresses, each associated with a different class of service from among the plurality of possible classes of service, wherein the means for providing the starting address of the program sequence comprises means for searching through a plurality of entries, each having a tag portion and a content portion indicating the starting address of a program sequence for a desired class of service, for an entry having a tag portion matching the key and a content portion indicating the starting address for a program sequence corresponding to the desired class of service indicated by the key, and, if a match is found, means for outputting the content portion of the matching entry and a signal indicating a hit condition, and, if a match is not found, means for outputting a signal indicating a miss condition;
a Content Addressable Memory (CAM) for holding a plurality of program sequences corresponding to the plurality of possible starting addresses; and
a processor to execute the program sequence corresponding to the provided starting address.
10. The packet processing system of claim 9 wherein the means for providing the starting address of the program sequence comprises means for addressing a plurality of addressable entries in the CAM, each indicating the starting address of a program sequence for a desired class of service, to access an entry addressed by the key and indicating the starting address for a program sequence corresponding to the desired class of service indicated by the key, and outputting the starting address indicated by the addressed entry.