A packet-switch system utilizes a linecard-to-switch (LCS) protocol to integrate linecards with a switch core. Since the linecards include a majority of the buffering of the system and are located physically away from switch core, the size of the switch core can be reduced in size. The LCS protocol is a label-swapping, credit-based, flow-control, which enables the system to operate without requiring such information as the number of port modules available within a switch core or what Qualities of Service (QoS) or multicast flows are available. In addition, the LCS protocol enables the linecards to contain and manage the majority of the buffers in the system, and also to control the data drop policy within the system.