ATM Operation and Maintenance
ATM Operation and Maintenance is a set of protocols defining how ATM interfaces can test their reliability. Not unlike many other OA&M protocols, ATM OAM relies a predefined packet format for its monitoring functions.
Packet Format
F4 (VP) OAM Cell Format
GFC |
VPI |
VCI |
PT |
CLP |
HEC |
OAM TYPE |
Function TYPE |
Function Specific Fields |
Reserved |
CRC-16 |
|---|---|---|---|---|---|---|---|---|---|---|
Same as User Cell |
3 (Segment) 4 (End-to-End) |
4-bits |
4-bits |
45-octets |
6-bits |
10-bits |
F5 (VC) OAM Cell Format
GFC |
VPI |
VCI |
PT |
CLP |
HEC |
OAM TYPE |
Function TYPE |
Function Specific Fields |
Reserved |
CRC-16 |
|---|---|---|---|---|---|---|---|---|---|---|
Same as User Cell |
Same as User Cell |
100 (Segment) 101 (End-to-End) |
4-bits |
4-bits |
45-octets |
6-bits |
10-bits |
Charts from
Types and Function Types
The following table identifies the type and function type field for the major OAM operations of Fault Management, Performance Management, Activation/Deactivation, and System Management.
OAM Type |
Function Types |
||
|---|---|---|---|
Fault Management |
0001 |
AIS |
0000 |
0001 |
RDI/FERF |
0001 |
|
0001 |
Continuity Check |
0100 |
|
0001 |
Loopback |
1000 |
|
Performance Management |
0010 |
Forward Monitoring |
0000 |
0010 |
Backward Reporting |
0001 |
|
Activation/Deactivation |
1000 |
Performance Monitoring |
0000 |
1000 |
Continuity Check |
0001 |
|
System Management |
1111 |
Non-Standardized |