Dae-Ub Kim

OAM and protection mechanisms for MPLS-TP packet transport networks

MPLS Transport Profile (TP) uses a subset of the existing MPLS toolkit which represents the minimal amount of functionality that is needed in a transport network environment. MPLS-TP delivers the richness and reliability of operations, administration and maintenance (OAM) mechanisms that are characteristics of transport technology at the same time as it will support packet-based services more efficiently than conventional transport networks. Also, MPLS-TP protection switching technologies in the area of packet transport networks have been developed to meet the requirement of sub 50ms traffic recovery in case of a link failure. This paper discusses the MPLS-TP OAM and protection mechanisms that are available and introduces the MPLS-TP equipment of ETRI.

Priority-based grant-aware scheduling for low-latency switching

This paper introduces new scheduling algorithms supporting low-latency switching. The proposed grant-aware (GA) algorithm improves the average delay performance by using the grant information of previous iteration. The simulation result shows that the average delay of GA algorithm is about one-tenth of the existing algorithm in high-load condition. We also introduce two priority-based scheduling algorithms grant-aware and priority-aware (GAPA) algorithm and cyclic scheduling with the longest-queue-first (C-LQF) algorithm. In the priority-based scheduling, the scheduling priority of VoQ is determined based on its queue size. GAPA and C-LQF consider the priority only after the first iteration to prevent the starvation problem. The simulation result shows that GAPA and C-LQF scheduling achieves better performance than GA in terms of average delay, maximum delay, and hotspot throughput.

Scheduling with machine-learning-based flow detection for packet-switched optical data center networks

A scalable, low-latency, high-speed, and energy- efficient data center network is a key element in the deployment of future large-scale data centers, and photonic switching has recently been recognized as a promising solution to fulfill these goals. In this study, we present a packet-switched optical network (PSON) architecture with centralized control for intra-data-center connectivity. For efficient PSON operation, intelligent yet low-complexity bandwidth-scheduling algorithms are critical. To align with realistic traffic flows in a data center, we consider “mice flow,” which occurs frequently but carries a small number of bytes, and “elephant flow,” which occurs occasionally but has a huge number of bytes. To classify traffic flows with different characteristics, we investigate various machine-learning (classification) techniques, such as C4.5 and Naïve Bayes Discretization, and compare their performance in terms of accuracy and classification speed. We also develop a priority-aware scheduling algorithm for packet switching, which is optimized for PSON, and is adaptive to flow classification under a dynamic traffic scenario. Numerical simulations show that our proposed scheduling algorithm assisted by flow-classification techniques can outperform a benchmark algorithm in terms of average delay and packet-loss ratio.

A protection switching management of two-layer transport networks with MPLS-TP over OTN

We study various options for the survivability in Multiprotocol Label Switching - Transport Profile (MPLS-TP) over Optical Transport Network (OTN) in terms of network resource usage. We present an efficient design model for protecting an MPLS-TP over OTN two layer networks to minimize the total amount of network resource. We also introduce the coordination behavior between two layers to coordinate timing of protection switches when using the hold-off timer. Lastly, we discuss the cost rates of current network elements based on our implemented system.