Preservation of priority traffic in communications systems

Abstract

Systems and methods for restoring lost or corrupted data in packets that traverse a packet-switched network. In some embodiments, a device at the edge of a packet switched network may restore data that was originally inserted in a packet header by a sender, but overwritten or bleached during transport over a network by identifying an associated packet, and transferring a value from the associated packet to the packet.

1 . A device in a communications network that receives a packet from a sender, the device configured to selectively use the packet to identify a different packet from a different sender and write data from the first packet to the different packet. 
     
     
         2 . The device of  claim 1  where the device is located in an operator network between a subscriber and a packet-switched network. 
     
     
         3 . The device of  claim 1  where the device identifies the different packet based on rearranging data in a selective one of the first packet and the different packet. 
     
     
         4 . The device of  claim 3  where the different packet is identified using a hash of the rearranged data. 
     
     
         5 . The device of  claim 1  where the data written from the first packet to the different packet causes the different packet to be processed differently by the communications network. 
     
     
         6 . The device of  claim 1  where the data is located in a field of an IP header in the packet. 
     
     
         7 . The device of  claim 1  where the device is configured to use data from the packet to identify sequential ones of a plurality of subsequent packets received from the different sender, at a time subsequent to the identification of different packet, where the device is configured to use less time identifying the sequential ones of the plurality of subsequent packets than used to identify the different packet. 
     
     
         8 . A device that receives a packet from a sender through a packet-switched network, the device configured to selectively restore a data value in the packet changed in transit through the packet-switched network, where the device determines the restored value from a plurality of potential values prior to the packet being received from the sender. 
     
     
         9 . The device of  claim 8  configured to determine the restored value from a plurality of potential values prior to the packet being sent from the sender. 
     
     
         10 . The device of  claim 8  configured to determine the restored value from a plurality of potential values prior to the packet being constructed by the sender. 
     
     
         11 . The device of  claim 1  in an operator network between a subscriber and the packet switched network. 
     
     
         12 . The device of  claim 11  where the restored value causes the packet to be processed differently by the operator network. 
     
     
         13 . The device of  claim 11  where the packet is the first packet identified from the sender by the device in an ongoing IP flow. 
     
     
         14 . A method comprising:
 receiving a first packet from a sender, the first packet having a header a plurality of fields;   rearranging the plurality of fields and using the rearranged plurality of fields to associate the first packet with a second packet;   writing a value received from one of the plurality of fields in a selective one of the first packet and the second packet to a corresponding field in the other selective one of the first packet and the second packet; and   sending the other selective one of the first packet and the second packet to a destination over a network.   
     
     
         15 . The method of  claim 14  where transferring the value to the other selective one of the first packet and the second packet changes its processing through the network. 
     
     
         16 . The method of  claim 14  where the step of rearranging the plurality of fields mirrors values in selective pairs of fields. 
     
     
         17 . The method of  claim 14  where the transferred value is at least one of a DSCP value and a Flow ID. 
     
     
         18 . The method of  claim 14  including the step of hashing the rearranged plurality of fields to produce a hashed value that identifies the selective one of the first packet and the second packet. 
     
     
         19 . The method of  claim 18  including the step of hashing a second plurality of fields in the header to produce a second hashed value that identifies a flow associated with the first packet, the second hashed value different than the first hashed value. 
     
     
         20 . The method of  claim 18  where the second hashed value is used to identify a subsequent packet from the sender, the identification used to process the subsequent packet faster than the first packet.