Patent ID: 6914878
Filing Date: 2005-07-05
Classification: H04L

Abstract:
1. A cell switch comprising: a first switch plane comprising a first switch core; a second switch plane comprising a second switch core; a sender switch port interface unit; N number of receiver switch port interface units; wherein the sender switch port interface unit applies maintenance cells to the N number of receiver switch port interface units in a cycle, the cycle comprising (1) non-inverted first plane maintenance cells sent via the first switch plane to each of the N number of receiver switch port interface units; (2) non-inverted second plane maintenance cells sent via the second switch plane to each of the N number of receiver switch port interface units; (3) inverted first plane maintenance cells sent via the first switch plane to each of the N number of receiver switch port interface units; and (4) inverted second plane maintenance cells sent via the second switch plane to each of the N number of receiver switch port interface units, the inverted first plane maintenance cells and the inverted second plane maintenance cells having at least a portion thereof inverted with respect to the corresponding non-inverted cell of the cycle; wherein the sender switch port interface unit sends maintenance cells by sending first plane maintenance cells via the first switch plane but not via the second switch plane and by sending second plane maintenance cells via the second switch plane but not via the first switch plane, each of the first plane maintenance cells and the second plane maintenance cells including a plane indicator which informs the receiver switch port interface unit whether the maintenance cell traveled through the first switch plane or the second switch plane; wherein the receiver switch port interface unit detects an erroneous switch plane when the first plane maintenance cells and the second plane maintenance cells from the sender switch port interface unit do not arrive in a predetermined sequence.