Dong-Yong Kwak

Mean starting potential fair queuing for high-speed packet networks

This paper proposes an efficient fair queuing algorithm, called mean starting potential fair queuing (MSPFQ), which has O(l) complexity for the virtual time computation while it has delay and fairness properties similar to starting-potential fair queueing (SPFQ). The key idea of MSPFQ algorithm is that it recalibrates the system virtual time to the mean value of the minimum possible virtual start times of HOL packets in each backlogged session. Through analysis and simulation, this paper shows that the proposed algorithm has good delay and fairness properties.

A CAC algorithm using CDV measurement

We propose a new CAC algorithm for traffic control in ATM networks which is based on a monitoring of the CDV tolerance /spl tau/ from the modified leaky bucket algorithm and uses a cell loss probability to decide whether a connection can be accepted or not. The proposed method can manage difficulty in deciding CDV tolerance /spl tau/ before a connection establishment phase and improve bandwidth utilization. This algorithm is compared with other CAC algorithm and shows good bandwidth utilization.

Implementation of a peak cell rate policer using the virtual scheduling algorithm

ATM technology adopts statistical multiplexing in order to use network resources efficiently, but it requires complicated traffic management. We describe the architecture of a policing device that implements the virtual scheduling algorithm among various algorithms for the peak cell rate policing and discuss some implementation issues. We also present a method of selecting the modes of the devices used to realize various policing schemes and show the experimental results for four different peak cell rate values to confirm that the device performs the policing function satisfactorily. We use the priority encoder to run the algorithm in parallel instead of sequentially, which reduce the operation time to a great extent. It takes about 850 ns for the device to produce the policed cell after receiving an incoming cell.

Adaptive CAC algorithms using measurement and estimation

To prevent network congestion due to unpredictable statistical fluctuation of broadband traffic pattern, a robust and reliable traffic control mechanism is required in an asynchronous transfer mode (ATM) network. We propose new adaptive connection admission control (CAC) algorithms which calculate the cell loss performance of related function blocks in a switch node using only a declared peak cell rate and an estimated mean cell rate to reduce the inaccuracy of the declared source parameters. We measure only the mean cell rate of the aggregate cell stream in a link to guarantee measurement accuracy. The proposed CAC algorithms can allow more relaxed source parameter declarations and thus guarantee efficient bandwidth utilization.

A restoration mechanism using K-shortest control paths

This paper presents a restoration scheme using k-shortest control paths. Our mechanism classified connections into two classes: real time class and non-real time class. In real time class, an ATM protection switching (APS) mechanism, a preventive restoration method defined in 1.630, is used as a restoration scheme that is realizing fast restoration and high reliability. In the non-real time class, the interactive restoration mechanism using k-shortest control paths is applied. The performance evaluations via simulations show the effectiveness of the proposed mechanism and the improved restoration ratio than the pure APS mechanism.

Hybrid self-healing mechanism with VP priority and dynamic bandwidth assignment policy in ATM networks

It is reasonable to restore the VP failures according to the VP priority level in respect of guaranteeing the QoS which is coupled with the VP priority. This paper proposes a new hybrid self-healing mechanism based on the VP priorities over the ATM networks. Backup VPs are assigned to restore the failures on the restoration domains such as the OAM segment or end-to-end VPC. Semi-dynamic VP restoration algorithms are used for the VPs which do not have backup VPs or whose backup VPs fail. The simulation results show that the proposed algorithm can restore higher priority VPs faster than the lower priority VPs.

A partial shaping mechanism for ATM networks

We propose a partial shaping mechanism (PSM) built upon the continuous-state leaky bucket (LB) mechanism which can control the shaping delay and the output buffer size. We assume that input traffic of the proposed shaping mechanism is the worst case traffic tolerated by the continuous-state LB mechanism and characterize traffic patterns that can depart from our shaping mechanism. We also compare shaping delay and output buffer size of the proposed shaping mechanism with the existing shaping mechanism which holds peak emission time strictly. Our results show that the proposed shaping mechanism can easily manage the shaping delay and the output buffer size than other mechanisms.