Operations, administration and management

Operation, Administration and Maintenance OAM is used to monitor the data transmission in ATM and Broadband ISDN at the bit and byte level.

There are defined the five levels, the lower three levels of F1, F2 and F3 to refer to the physical layer and the transfer layer (over PDH or SDH), the top two levels of F4 and F5 on the ATM layer.

  • F1 refers to the bottom layer between the transmitter / receiver, where no change in the data occur
  • F2 describes the plane between two LT ( Line Terminals )
  • F3 denotes the entire transmission path
  • F4 is the Virtual Path ( VP) level
  • F5 is the Virtual Channel (VC ) level

OAM on ATM level

The following functions are defined on the ATM layer (F4 and F5).

  • Fault Management - AIS ( Alarm Indication Signal ) and RDI (Remote Defect Indication ) are used to alert other nodes on error, for example, break a line. CC ( Continuity Check ) is used for the continuous monitoring of a compound
  • Performance Monitoring - Measurement of cell loss
  • Activation / Deactivation - Activation and deactivation of performance monitoring.

OAM functions can be performed ( end-to -end ), but also a partial distance (segment ) by segments are defined over the entire path of a VCC ( Virtual Channel Connection) or VPC (Virtual Path Connection).

To distinguish the OAM cell from the VCC user cells 3 and 4 are to VP - level used in the VC- layer, the values ​​4 and 5 in the cell header PT field. The payload of the OAM cell contains an identifier of the feature and function-specific fields.

  • ATM network
  • ISDN
  • VoIP
Asynchronous Transfer Mode
621815
de