EXFO FTB-8510B Guia Del Usuario página 1182

System Tab
Default Test Preferences
532
For ODU2 background traffic (ODUflex client):
The above example shows that ODU2 that contains ODUflex
foreground traffic uses ODUflex (one tributary slot) background or
Unallocated traffic.
For ODU2 background traffic (ODU0 client):
The above example shows that ODU2 that contains ODU0
foreground traffic uses ODUflex (one tributary slot) background or
Unallocated traffic.
FTB-8100 Series Transport Blazer