Man-Soo Han

Efficient dynamic bandwidth allocation for FSAN-compliant GPON

We suggest an immediate allocation with colorless grant (IACG) method for dynamic bandwidth allocation of a gigabit passive optical network (GPON) system. The suggested method is based on the GigaPON Access Network (GIANT) media access control (MAC) method. The IACG method can assign the transmission bandwidth regardless of the value of a scheduling counter, whereas the GIANT MAC method can assign the transmission bandwidth only when the scheduling counter has a value of 1. Also, unlike the GIANT MAC method, the IACG method utilizes the unallocated remainder of the transmission bandwidth. At the end of scheduling, the IACG MAC method assigns the unallocated remainder to each optical network unit (ONU) with an equal share. Using computer simulations with the self-similar traffic model, we show that the IACG method dramatically outperforms the GIANT MAC method in mean delay and frame-loss rate.

Minimum Credit Method for Dynamic Bandwidth Allocation in EPON

We suggest a new minimum credit method for the dynamic bandwidth allocation in EPON. In the suggested method, to eliminate the unused transmission time-slot, each ONU requests no more than a predetermined maximum. We analyze the upstream channel resource wastage when traffic is light. Based on the analysis, we derive a minimum credit that eliminate the upstream channel resource wastage. The OLT estimates a traffic load and grants a minimum credit when the request is smaller than the minimum credit and traffic is light. Using simulation, we show the minimum credit discipline is superior than the existing methods in the mean delay and the frame loss rate.

Enhanced Class-of-Service Oriented Packet Scheduling Scheme for EPON Access Networks

A fast class-of-service oriented packet scheduling (FCOPS) has a service fairness problem since a credit pool for a service class is initialized at the beginning of a transmission cycle whose starting moment is fixed at a specific ONU. To remedy the service unfairness of FCOPS, we suggest an enhanced class-of-service oriented packet scheduling (ECOPS) that uses a new initialization cycle whose starting moment is fairly distributed to each ONU. Also, ECOPS generates a colorless grant to utilize the resource wastage, when traffic is light and the total sum of grants of an ONU is less than a minimum size. Using simulation, we validate ECOPS as superior to FCOPS in the mean delay and the service fairness.

Dual Thresholds Method for Dynamic Bandwidth Allocation in EPON

We suggest a dual thresholds method for the dynamic bandwidth allocation in EPON. In the suggested method, a buffer in ONU has two thresholds and ONU generates a normal request and a greedy request based on the two thresholds. Also, OLT estimates the overall traffic load and grants the greedy request when estimated traffic is light. We study upstream channel resource wastage and show the suggested method decreases the upstream channel resource wastage. Using simulation, we validate the dual thresholds method is superior to the existing methods in the mean delay.

Stability analysis of input-buffered packet switches with maximal size matching

We analyze the stability of input-buffered packet switches with virtual output queue (VOQ), maximal size matching (MSM) algorithm and speedup. We first introduce a queueing system for the stability analysis. Using supplementary variables to represent the packet switching mode and remaining packet service time, we describe the behavior of the queueing system. Then, we propose a Lyapunov function to prove speedup of 2 is sufficient to achieve 100 % throughput in input-buffered packet switches with MSM algorithm.

Simple iterative matching for input and output buffered switch with multiple switching planes

We present a simple iterative matching for an input and output buffered switch with multiple switching planes. The suggested algorithm is based on iSLIP and consists of request, grant and accept steps. The pointer update scheme of iSLIP is simplified in the suggested algorithm to enhance a match efficiency and a service fairness. In addition, we show a switch performance is improved when the suggested algorithm is used with an occupancy level of a queue. Using computer simulation under Bernoulli traffic, we show the suggested algorithm is better than iSLIP for cell scheduling of input and output buffered switches.