Patent ID: 8588224

Claim:
A switching network, including: an upper tier including a master switch and a lower tier including a plurality of lower tier entities, wherein the master switch includes: a plurality of ports each coupled to a respective one of the plurality of lower tier entities, each of the plurality of ports including a plurality of virtual ports each corresponding to a respective one of a plurality of remote physical interfaces (RPIs) at the lower tier entity coupled to that port, wherein data traffic communicated between the master switch and RPIs on the plurality of lower tier entities is queued to virtual ports among the plurality of virtual ports that correspond to the RPIs on lower tier entities with which the data traffic is communicated; and a switch controller that switches data traffic between the plurality of ports; wherein the master switch enforces priority-based flow control (PFC) on data traffic of a given virtual port by transmitting, to a lower tier entity at which a particular RPI corresponding to the given virtual port resides, a PFC data frame specifying priorities for at least two different classes of data traffic communicated by the particular RPI; wherein: the lower tier entity comprises a follower switch configured in flow through mode; the particular RPI comprises a data port on the follower switch; and the follower switch receives the PFC data frame, removes an RPI identifier identifying the particular RPI from the PFC data frame to obtain a standard PFC data frame, and transmits the standard PFC data frame via the data port corresponding to the particular RPI.