OAM function of ATM layer

Well, today's chief telecommunications engineer's material is an ATM. They are problems of behavior and the operation, etc. of the OAM cell this time though the OAM cell calls the cell that transmits information on the maintenance operation management in the cell of the ATM. Then, today's material is [kochira] ↓↓.



- OAM function of ATM layer



The warning transfer function is achieved by sending the OAM cell that displays the breakdown to VP and VC from the device that detects the breakdown of a physical layer or the ATM layer.

These sentences are correct.
- The warning transfer function: The breakdown notification is done by sending the OAM cell (AIS cell and RDI cell) that displays the breakdown to VP or VC from the device that detects the breakdown of a function, a physical layer or the ATM layer that notifies VP and VC not to be able to be used when the breakdown occurs in the transfer function of a physical layer or the ATM layer.
VP-RDI: Signal that is judged breakdown, and sent at transmitting end when user information cell or OAM cell doesn't receive it on receiving side longer than fixed time
Signal to notify direction of reception side from the connection point the breakdown when breakdown of VP-AIS:VP connection is detected



The loop back cell that receives it is sent back as it is in the device specified for a halfway mark though the connection of the communication of a specified section of arbitrary VP and VC confirmation uses the loop back function.

These sentences are wrong.
- The OAM cell for the loop back is sent from the device on the edge of the section where it wants to confirm the communication connection. The number of the device on the other edge is written in the loop back cell as a halfway mark. This loop back cell is sent in the counter direction when received with the device for which the loop back cell is specified for a halfway mark. The communication connection in a specified section is confirmed first by receiving the turned loop back cell in the device that sends the loop back cell.
- Moreover, the meaning of this explanation is not understood. ｡｡

- Anyway, the part of "Send it back as it is" is a mistake, and "It rewrites in a specific value and send it back" answers correctly.
- The least significant bit of the loop back display field displays whether the loop back has already been executed by the pool algebra form. It is confirmed whether the loop back is executed by this field in the ATM layer. This field is coded to "00000001" in the source point. In the loop back point, it replaces it with "00 million".



The number of cell losses and the number etc. of mistakes of VP and VC can be confirmed on the receiving side according to information on the OAM cell for the continuity check.

These sentences are wrong.
- The number of cell losses and the number etc. of sign mistakes of VP and VC cannot be confirmed by using OAM cell information for the reception side continuity check.
- Anyway, it seems to be "It is not possible to judge on the receiving side. "



The continuity check function and the performance monitoring function start/are stopped by start/stop OAM cell. Which function start/is stopped is specified in peculiar to the function of the payload field.

These sentences are wrong.
- Which function start/is stopped is specified by the OAM function type of the payload.
- Continuity check or performance monitoring function or which is used is specified by "OAM function type".



Well, how about you?It is caught to the problem if it studies really neatly, and it doesn't remember surely if it is necessary to judge the correction from either that rewrites only ending of a words of sentences and sentences that can be taken. Because frequency of setting questions is considerably high, let's work hard and remember the OAM relation in the problem of the ATM. Then, around here today