System and method for egress packet marking

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 any one or more of Virtual Local Area Network Priority (VLAN VPRI), Multi-Protocol Label Switching Experimental Use (MPLS EXP), and Internet Protocol version 4 Type of Service/version 6 Traffic Class (IPv4ToS/IPv6TC) 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 any one or more of VLAN VPRI, MPLS EXP, and IPv4ToS/IPv6TC QoS fields with an index, (2) values of the any one or more of VLAN VPRI, MPLS EXP, and IPv4ToS/IPv6TC 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 any one or more of VLAN VPRI, MPLS EXP, and IPv4ToS/IPv6TC QoS fields in the packet;
• wherein the packet marker processor, upon executing these commands, individually selects, for each of the any one or more of VLAN VPRI, MPLS EXP and IPv4ToS/IPv6TC 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 egress mark control 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.

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 method of 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:

• holding in one or more memories (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 of the packet prior to modification thereof by the packet modification system, and (3) one or more egress mark commands;
• and
• selectively updating the one or more QoS fields of the packet, comprising individually selecting, for each such field, 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.