Patent ID: 6747954
Filing Date: 2004-06-08
Classification: H04L

Abstract:
A method of operating an ATM switch having plural switch ports connected to a switch core, the switch core having plural cross point buffers, the method comprising:(1) maintaining, at the switch core, pollstate status information indicative of which of selected ones of the cross point buffers of the switch core have service cells stored therein; (2) sending a retrieve pollstate control cell from an origination switch port to a row column unit of the switch core when the origination switch port desires to ascertain the pollstate status information, the retrieve pollstate control cell being terminated at the row column unit; (3) in response to the retrieve pollstate control cell, sending the pollstate status information in a pollstate status control cell from the row column unit to the originating switch port, the pollstate status control cell being originated at the row column unit; and (5) using the pollstate status information obtained from the pollstate status control cell for determining to which of the selected ones of cross point buffers of the switch core service cells can be transmitted from the originating switch port, the service cells including switchable user data but neither the retrieve pollstate control cell nor the pollstate status control cell being switched through the switch core.