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LTP-8X optical line terminal
Chapter 21.
DBA Configuration
Introduction
This Chapter considers DBA configuration for ONT.
GPON technology implies that all ONTs of one GPON channel use common communication medium
(fibre). It is necessary to provide a mechanism that will ensure data transfer from all ONTs without
collisions. The mechanism is called dynamic bandwidth allocation (DBA) and ensures allocation of time
intervals in OLT for data transfer to ONT.
A logical unit of the DBA algorithm is Alloc-ID (allocation) with a corresponding T-CONT (traffic counter)
on the ONT side. Data transfer parameters (frequency, transmission window) are separately configured
for every Alloc-ID (T-CONT) and are referred to as service level agreement (SLA).
G.984.3 provides several SLA combinations called T-CONT type. There are the following T-CONT types:
— T-CONT type 1 with a fixed bandwidth only. It is suitable for a traffic which is transferred at a constant
speed (or with very low variations) and is sensitive to delays and jitter.
— T-CONT type 2 with a guaranteed bandwidth only. This type is suitable for a bursty traffic with a well
defined upper bound, without strict delay and jitter restrictions.
— T-CONT type 3 is a counter with a guaranteed bandwidth and a possibility to allocate a best-effort
bandwidth. This type is suitable for a bursty traffic with peak values that requires a certain throughput
to be guaranteed.
— T-CONT type 4 allows allocation of a best-effort bandwidth without fixed or guaranteed bandwidths.
This type is suitable for a bursty traffic with peak values that does not require any guaranteed
throughput.
— T-CONT type 5 is a counter with fixed and guaranteed bandwidths and a possibility to allocate a best-
effort bandwidth. This type summarises all other types and is suitable for most types of traffic.
