Oversubscription buffer management

A rack switch, comprising:

• a plurality of ingress ports;
• an oversubscription buffer configured to receive packets from the plurality of ingress ports and provide the received packets for processing by the rack switch;
• and
• a packet flow control configured to monitor an occupancy level of the oversubscription buffer and to initiate adjustment of an ingress packet rate of the oversubscription buffer in response to the occupancy level of the oversubscription buffer.

A method for oversubscription control of a rack switch, comprising:

• receiving packets through at least one of a plurality of ingress ports of the rack switch;
• providing the packets to an oversubscription buffer of the rack switch and to a virtual oversubscription buffer associated with the oversubscription buffer, where a packet drain rate of the virtual oversubscription buffer is less than a packet processing rate of the rack switch;
• determining an occupancy level of the virtual oversubscription buffer;
• and
• initiating adjustment of an ingress packet rate of the oversubscription buffer in response to a comparison of the occupancy level with a predefined threshold.