atmIfVpcRxOamCellCongestionState 1.3.6.1.4.1.562.2.4.1.114.4.120.1.55

This attribute contains the current state of the receive side OAM cell congestion for this connection. Its value reflects whether the rate of received OAM cells for this connection is below a specified threshold. The connection maintains a count of the number of OAM cells which are terminated per second. Once that count exceeds the specified threshold, extraction of all OAM cells for this connection is disabled for a period of one minute. This is a congestion management mechanism to prevent the processor from being overloaded with handling OAM cells for a particular connection. This mechanism ensures that tasks, such as trunks obtain enough processor cycles to remain in service, and are not adversely affected by excessive rate of OAM cells on a particular connection. The value is good when the rate of received OAM cells is less than the allowed threshold. The value is bad when the arrival rate has exceeded the allowed threshold. It remains bad for one minute, before returning to good again. During this timeout, extraction of all OAM cells is disabled for this connection. As a result, other loopback failure conditions may occur. The value is unknown when the application has not yet begun to use this connection. An example is the Test component before a test has been started. Each type of OAM cell is counted separately. The threshold for AIS cells is three cells per second. If more than three AIS cells are received within a one second interval, this attribute is set to bad. The threshold for RDI cells and each loopback type is also three, but the threshold for trace cells is 250 per second. The state of this attribute has no direct effect on the value of the operStatus attribute or on the number of troubled connections.