DBA algorithm for various traffic services over ATM-PON system

Abstract

In ATM-PON, the MAC protocol should guarantee the fairness and QoS of user data. The efficient MAC protocol would make multiple ONUs dynamically share the given bandwidth. This thesis proposes frame format, scheduling, DBA algorithm and grant allocation algorithm for MAC protocol in ATM-PON that comply with the specifications of ITU-T G.983.1 and G.983.4. The proposed DBA scheme deals with the various traffic services such as CBR(DBR class 1), rtVBR(SBR class 2), nrtVBR(DBR class 2), nrtVBR(SBR class 2) and UBR. This DBA algorithm assigns upstream bandwidth to each T-CONT considering its traffic characteristics. This thesis also presents two typical ONU types. One uses four T-CONTs(T-CONT type 1, 2, 3, and 4) that are mapped with the above ATM service categories and the other has one T-CONT type 5. The performance is evaluated by computer simulation in point of view of average queue-length, maximum queue-length and CDV(Cell Delay Variation). Traffic configuration-1 and -2 are used in simulation. The former is offered by FSAN and the latter is the modified traffic configuration-1. When traffic configuration-1 is applied to PON system with 32 ONUs, the most average queue-length of static mode is about 12000 cells. It means that PON system like this can statistically cover 32 ONUs. But in view point of maximum queue-length, PON system in static mode can support 14 ONUs at the most. And observing average queue-length of each T-CONT, PON system in static mode may not support the traffic characteristics of user data. On the other side, PON system that is applied the proposed DBA algorithm to, shows better performances, that is, when 32 ONUs are accommodated, the most average queue-lengths for ONU-1 and ONU-2 are about 8400 cells and about 7200 cells respectively. And in view point of maximum queue-length, PON system with ONU-1 can cover 17 ONUs and one with ONU-2 can cover 19 ONUs. These results show that the proposed DBA algorithm makes PON system able to...