Enhanced Linear Protection Switching Methods Supporting Dual Node Interconnection in Packet Transport Networks

Kim, Dae-Ub,Ryoo, Jeong-dong,Cheung, Taesik,Song, Jongtae,Kim, Kwangjoon IEEE 2018 Journal of Lightwave Technology Vol.36 No.13

<P>In this paper, we discuss the issues of supporting protection switching in multiple recovery domains (MRDs). In MRDs, dual node interconnection (DNI) between two adjacent domains is essential to provide reliable services for customers whose traffic traverses multiple domains. Existing linear protection switching solutions in packet transport networks, such as multiprotocol label switching—transport profile (MPLS-TP) and Ethernet, support protection of an end-to-end flow between two end nodes in a recovery domain; however, they do not provide DNI capability between two recovery domains. We propose a DNI scheme with linear protection switching technology and analyze its advantages. In the case of a large number of connections affected by a single failure in MRDs protected by linear protection, traffic recovery can be delayed owing to the signaling associated with excessive simultaneous signal fail triggers. We design a collective interconnection message (CIM) scheme that improves the performance of linear protection DNI (LP-DNI) in MRDs and confirms that the CIM mechanism reduces restoration time significantly. By extensive simulations on link and node failures scenarios, we investigate different combinations of LP-DNI and existing ring protection processes to establish the influence of service resiliency in MRDs.</P>

노드 이중화를 위한 이중 프로세스 선형 보호 절체 방법

김대업(Dae-Ub Kim),김병철(Byung Chul Kim),이재용(Jae Young Lee) 대한전자공학회 2016 전자공학회논문지 Vol.53 No.9

현재 전달망의 핵심기술은 링크 또는 노드 장애가 발생했을 경우에 경로 이중화를 통해 50ms이내에 망을 복구하는 OAM 및 보호절체 기술이다. 개별 통신사업자, 지방/중앙 정부, 중요 기업의 전달 망은 장애에 대한 실시간 망 복구를 위해 보호 서브네트워크를 개별적으로 설정, 관리되고 있다. 그래서 개별 보호 서브네트워크의 종단 노드에 대해 노드 이중화를 적용하여 종단 노드 장애에 대해 대비하는 것이 중요하다. 하지만 MPLS-TP, 캐리어 이더넷과 같은 패킷 전달망에서 선형 보호절체가 적용되는 보호 서브네트워크는 이중 노드 상호 연결 방안이 존재하지 않는다. 비록 이더넷 링 보호절체는 이중 노드 상호 연결방안을 포함하고 있지만 이더넷 링 보호절체의 기술적 특성상 연결 노드에서 장애가 발생하면 전이 트래픽이 급격하게 증가될 수 있다. 본 논문에서는 보호 서브네트워크에서 연결 노드 이중화를 위한 선형 보호절체 적용 방안을 제시한다. 그리고 링크와 상호 연결 노드의 장애에 대한 여러 실험을 통해 제안된 선형 보호와 링 보호 프로세스의 다양한 조합이 어떻게 다중 보호 서브네트워크에서 서비스 트래픽의 복구 탄력성에 영향을 미치는 지를 분석한다. The core technologies of the current transport network are OAM and protection switching to meet the sub-50ms protection switching time via a path redundancy when a link or node failure occurs. The transport networks owned by public network operators, central/local governments, and major enterprises are individually configured and managed with service resiliency in each own protected sub-network. When such networks are cascaded, it is also important to provide a node resiliency between two protected sub-networks. However, the linear protection switching in packet transport networks, such as MPLS-TP and Carrier Ethernet, does not define a solution of dual node interconnection. Although Ethernet ring protection switching covers the dual node interconnection scheme, a large amount of duplicated data frames may be flooded when a failure occurs on an adjacent (sub) ring. In this paper, we suggest a dual node interconnection scheme with linear protection switching technology in multiple protected sub-networks. And we investigate how various protected sub-network combinations with a proposed linear or ring protection process impact the service resiliency of multiple protected sub-networks through extensive experiments on link and interconnected node failures.

10기가비트 이더넷 물리계층 관리를 위한 인터페이스 변환장치

김대업(Dae Ub Kim),정해원(Hae Won Jung) 대한전자공학회 2002 대한전자공학회 학술대회 Vol.2002 No.11

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

Song, Jongtae,Han, Kyeong-Eun,Kim, Dae-Ub,Park, Chansung,Kim, Kwangjoon Springer-Verlag 2018 PHOTONIC NETWORK COMMUNICATION Vol.36 No.2

Implementation of Absolute Delay Differentiation Scheme in Next-Generation Networks

백정훈(Jung Hoon Paik),김대업(Dae Ub Kim),주범순(Bheom Soon Joo) 대한전자공학회 2008 電子工學會論文誌 IE (Industry electronics) Vol.45 No.1

본 논문에서는 차세대 패킷 네트워크에서의 서비스 품질 기능 고도화를 목적으로 절대적 지연 차별화 기능을 제공하는 알고리듬을 제시하고 시뮬레이션을 통해 성능 분석을 수행한다. 또한, 제안된 알고리듬을 XPC 860 CPU 기반의 시험 보드상에서 VHDL 로 구현하여 실제 트래픽 입력 상황하에서의 성능 분석을 수행한다. 제안된 알고리듬은 매 시간 구간마다 입력되는 트래픽을 측정하고 이를 기반으로 다음 시간 구간 동안 입력될 트래픽의 양을 예측한 후 실제로 다음 시간 구간 동안에 입력된 트래픽과 비교하여 오차분을 도출하여 이를 다음 타임 슬롯의 지연 차별화 동작에 지속적으로 반영하는 것이 특징적 요소이므로 오차분을 고려하지 않는 기존 방식에 비해 버스트 트래픽에 대하여 우수한 적응성을 보여준다. 제안된 방식의 성능은 시뮬레이션과 실제 보드상에서의 시험을 통해 절대적 지연 목표를 충족시킴과 동시에 기존 방식에 비해 버스트 트래픽에 대하여 성능 개선 효과가 달성됨이 확인된다. In this paper, an algorithm that provisions absolute differentiation of packet delays is proposed, simulated, and implemented with VHDL on XPC 860 CPU based test board with an objective for enhancing quality of service (QoS) in future packet networks. It features a scheme that compensates the deviation for prediction on the traffic to be arrived continuously. It predicts the traffic to be arrived at the beginning of a time slot and measures the actual arrived traffic at the end of the time slot and derives the difference between them. The deviation is utilized to the delay control operation for the next time slot to offset it. As it compensates the prediction error continuously, it shows superior adaptability to the bursty traffic as well as the exponential traffic. It is demonstrated through both simulation and the real traffic test on the board that the algorithm meets the quantitative delay bounds and shows superiority to the traffic fluctuation in comparison with the conventional non-adaptive mechanism.

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

Wang, Lin,Wang, Xinbo,Tornatore, Massimo,Kim, Kwang Joon,Kim, Sun Me,Kim, Dae-Ub,Han, Kyeong-Eun,Mukherjee, Biswanath IEEE 2018 Journal of optical communications and networking Vol.10 No.4

<P>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.</P>

네트워크 스케줄링 알고리즘의 병렬 처리 동향

박찬성(Chansung Park),송종태(Jongtae Song),김대업(Dae-Ub Kim),한경은(Kyeong-Eun Han),김광준(Kwangjoon Kim) 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.6

Distributed memory access architecture and control for fully disaggregated datacenter network

Kyeong-Eun Han(Kyeong-Eun Han),Ji Wook Youn(Ji Wook Youn),Jongtae Song(Jongtae Song),Dae-Ub Kim(Dae-Ub Kim),Joon Ki Lee(Joon Ki Lee) 한국전자통신연구원 2022 ETRI Journal Vol.44 No.6

In this paper, we propose novel disaggregated memory module (dMM) architecture and memory access control schemes to solve the collision and contention problems of memory disaggregation, reducing the average memory access time to less than 1 μs. In the schemes, the distributed scheduler in each dMM determines the order of memory read/write access based on delay-sensitive priority requests in the disaggregated memory access frame (dMAF). We used the memory-intensive first (MIF) algorithm and priority-based MIF (p-MIF) algorithm that prioritize delay-sensitive and/or memory-intensive (MI) traffic over CPU-intensive (CI) traffic. We evaluated the performance of the proposed schemes through simulation using OPNET and hardware implementation. Our results showed that when the offered load was below 0.7 and the payload of dMAF was 256 bytes, the average round trip time (RTT) was the lowest, ~0.676 μs. The dMM scheduling algorithms, MIF and p-MIF, achieved delay less than 1 μs for all MI traffic with less than 10% of transmission overhead.