Nec Corporation

Toshihiko Sugaya

Yumi Tanaka

In an OAM detecting apparatus and an OAM detecting method, normal lines are not adversary influenced at occurrence of failure and one failed position can be recognized at occurrence of a double failure. A timer counter comparator generates a discard signal when a timer counter value measuring a predetermined time equal to or less than one second after reception of an OAM cell is less than a reference value. A failed position display and comparator compares, when a failed position display change flag is &ldquo;0&rdquo;, failed position display information of a new OAM cell received with failed position display information previously stored, and generates a discard signal when the comparison results in mismatching. When the flag is &ldquo;1&rdquo;, the display and comparator compares the failed position display information of a new OAM cell received with the failed position display information previously stored, and does not generates a discard signal even when the comparison results in mismatching. The display and comparator updates the failed position display information previously stored to the failed position display information of the new OAM cell and sets the flag to &ldquo;0&rdquo;.

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Fukuoka, Japan

Toshihiko Sugaya