Patent ID: 7613209

Claim:
In a packet modification system for receiving packets, previously classified by a packet classification system, from one or more switch-side devices, modifying the packets to facilitate egress thereof from the packet modification system, and transmitting the modified packets to one or more network-side devices, a packet marker for selectively updating one or more quality of service (QoS) fields in such a modified packet, prior to egress thereof from the packet modification system, comprising: one or more memories for holding (1) a table associating values for the one or more QoS fields of the packet with an index, (2) values of the one or more QoS fields taken from the packet prior to modification thereof by the packet modification system, and (3) one or more egress mark commands; and a packet marker processor for utilizing a link associated with the packet by the packet classification system to access the one or more egress mark commands stored in the one or more memories, and executing such commands to selectively update the one or more QoS fields of the modified packet; wherein the packet maker processor, upon executing these commands, individually selects, for each of the one or more QoS fields, the process used for updating the field from amongst at least the following processes: updating the field using the value of the field taken from the packet prior to modification thereof by the packet modification system as stored in the one or more memories; updating the field using a value obtained by performing a table lookup operation on the table stored in the one or more memories, using as an index in said operation a value obtained or derived from information associated with the packet by the packet classification system; and updating the field using a value derived from at least one of the one or more egress mark commands; wherein at least one of the one or more QoS fields of the packet are selected from the group consisting of a Virtual Local Area Network Priority (VLAN VPRI) field, a Multi-Protocol Label Switching Experimental Use (MPLS EXP) field, and an Internet Protocol version 4 Type of Service/version 6 Traffic Class (IPv4ToS/IPv6TC) field.