Televes 769501 - Dynamic Bandwidth Allocation (DBA)

20
GPON ONT
Figure 2-11: Upstream QoS Diagram
2.14.3 Dynamic Bandwidth Allocation (DBA)
The DBA (Dynamic Bandwidth Allocation) is available in order to optimize the upstream bandwidth. This mechanism consists in dening an ad-
equate T-CONT to the service trac in question. There are ve types of T-CONT, dened by the Fixed, Assured and Maximum Parameters:
Type 1: Only xed Bandwidth;
Type 2: Only Assured Bandwidth;
Type 3: Assured+Maximum Bandwidth;
Type 4: Only Maximum Bandwidth (Best Eort);
Type 5: Fixed+Assured+Maximum Band
T-CONT Type 1 Type 2 Type 3 Type 4 Type 5 Units
Fixed BW- R
F
R
F1
0 0 0 R
F5
[b/s]
Assured BW- RA 0 R
A2
R
A3
0 R
A5
[b/s]
Max Bw - RM R
M1
= R
F1
R
M2
= R
A2
R
M3
> R
A3
R
M4
R
M5
>
R
F5
+ R
A5
[b/s]
Bandwidth Eligi-
bility
0 0 Non-Assured
BW - R
NA
Best-Eort
- R
BE
R
NA
/ R
BE
Table 2-1: T-CONT types denition
In each GPON interface there are 1024 Alloc-ID (T-CONT identiers) available, provided to manage ONT services. They are distributed in the fol-
lowing way:
Alloc-ID Allocation Type
0-127 Default Alloc-ID (Dynamic or Static)
128-255 Reserved
256-639 Dynamic or Static
640-1023 Static
Table 2-2: Alloc-ID’s distribution by T-CONT type