Patent ID: 7466653
Filing Date: 2008-12-16
Classification: H04L

Abstract:
1. A stackable network device comprising: a plurality of stack units interconnected by a plurality of stacking links, wherein each of the stack units comprises a control plane processor, a plurality of ports to receive and transmit packets of data in parallel with an external network, and a forwarding engine to transfer the packets of data between the ports in accordance with the control plane processor, wherein the control plane processor in a first one of the stack units identifies a path for a planned data flow within the stackable network device, the identified path comprising a plurality of the stack units interconnected in series by one or more of the stacking links and comprising a first stack unit that is the source of the planned data flow and a last stack unit that is the destination of the planned data flow, wherein the planned data flow has a quality of service; wherein the control plane processor in the first one of the stack units transmits a path message over the identified path; wherein the control plane processors in each of the stack units, other than the first one of the stack units, in the identified path, receive the path message from a next upstream one of the stack units in the identified path, and transmit the path message to a next downstream one of the stack units in the identified path; wherein the control plane processor in the last one of the stack units in the identified path transmits a reserve message over the identified path; wherein the control plane processors in each of the stack units, other than the last one of the stack units, in the identified path, receive the reserve message from a next downstream one of the stack units in the identified path, and make an attempt to reserve resources on the one of the stacking links connected to the next downstream one of the stack units according to the quality of service of the planned data flow; and wherein the control plane processors in each of the stack units, other than the first and last ones of the stack units, in the identified path, transmit the reserve message to a next upstream one of the stack units in the identified path when the attempt to reserve resources is successful.