Dujeong Lee

Distributed potential field based routing and autonomous load balancing for wireless mesh networks

Congested hot spots and node failures severely degrade the performance of wireless mesh networks. However, conventional routing schemes are inefficient in mitigation of the problems. Considering analogy to physics, we propose a novel distributed potential-field-based routing scheme for anycast wireless mesh networks, which is robust to sudden traffic and network perturbations, effectively balancing load among multiple gateways and mesh nodes with little control overhead. Simulation results exhibit autonomous load balancing and failure-tolerant performance in wireless mesh networking.

Efficient Ethernet Ring Mesh Network Design

Ethernet ring protection (ERP) is an emerging solution for carrier-grade optical Ethernet networking developed as an ITU-T recommendation. The most recent development of the ERP technique provides multi-ring protection in a mesh packet transport network. The ERP configuration and capacity planning in a ring mesh topology can be optimized in the selection of the interconnected ring hierarchy and logical loop prevention block positions. This paper reports the first investigation to understand the designing principles of protected Ethernet ring mesh networks and proposes an optimized design scheme for cost-effective and reliable ERP networking.

Multipath Video Real-Time Streaming by Field-Based Anycast Routing

Wireless mesh networking (WMN) for video surveillance provides a strong potential for rapid deployment in a large community, for which reliability and survivability for real-time streaming are the key performance measure. However, current routing protocols do not provide a robust solution to meet video transmission requirements such as providing load balancing for the high data rate and delay requirements. We propose an application of field-based anycast routing (FAR) protocol, which utilizes rapid routing dynamics inspired by an electrostatic potential field model governed by Poissons equation. This routing metric takes into account geometric proximity and congestion degree in order to increase delivery ratio and decrease end-to-end delay, which determine the quality of the delivered video. In addition, FAR protects node failure with an on-the-fly rerouting process that guarantees the continuity of video streaming. Simulation results show 100% delivery ratio in congestion situations and it shows tolerance to different delay requirements compared with AODV and FDMR protocols in terms of delivering real-time and non real-time video surveillance which verifies FAR as a strong candidate for video transmission over WMN.

Reliable Network Design for Ethernet Ring Mesh Networks

A Novel Design Optimization For Reliable Networking Is Investigated In Ethernet Ring Mesh Networks With The Itu-T G.8032 Ethernet Ring Protection Recommendation. Designing An Ethernet Ring Mesh Consisting Of Multiple Rings To Achieve The Maximum Network Availability Is An Np-Complete Problem. We Show That A Graph With Vertex Connectivity Equal To Or Greater Than Two Is A Sufficient Condition For Designing An Ethernet Ring Mesh. A Novel Design Rule With An Efficient Heuristic Algorithm Is Proposed To Find A Design Close To An Optimal Ethernet Ring Mesh In Terms Of Maximum Network Availability. Compared With An Optimal Network Design Algorithm With An Exponential Enumeration Search Cost, The Heuristic Algorithm Achieves Network Availability Nearly As High As That Of An Optimal Design At A Polynomial Cost.

Cost-effective topology design for HSR resilient mesh networks

High-availability seamless redundancy (HSR) protocol provides a zero failover time protection applicable to any Ethernet topology. HSR is also capable of tolerating multiple simultaneous failures, which further promotes the application of packet-based Ethernet protection. Deploying HSR in mesh networks may incur a significant unnecessary cost if not designed carefully. This paper addresses the problem of minimizing the cost of HSR mesh networks given a network availability constraint. We first develop an enumeration-based method to find the optimal design. However, due to the NP-hard complexity of the problem, this is limited to only small networks. Hence, a novel two-step heuristic algorithm is proposed. The algorithm first searches a design of an initial mesh topology compliant with HSR survivability conditions, and then an evolution process takes place to find a modification of the initial topology that satisfies the required availability. The simulation results show that our heuristic algorithm achieves a comparable performance close to optimal while being computationally scalable.

Energy-aware algorithms for network-assisted device-to-device content delivery networks

Due to explosively growing demands for mobile contents, network-assisted device-to-device (D2D) content delivery networks (CDNs) have emerged as an ancillary resource for content services. The key characteristics of the network system is that mobile devices are used as cache servers for localized content delivery via D2D communication that controlled by a cellular network. Recently, a few studies have reported that it can provide better content delivery performance at a low cost. However, mobile devices operating as cache servers have to inevitably make sacrifices for energy consumption by delivering requested contents to neighboring requesters. In this paper, we tackle the critical problem and finally propose two energy-aware algorithms: request routing and MAC scheduling. Simulation results exhibit that the algorithms can reconcile conflicting objectives such as extending the D2D network lifetime and achieving good content delivery performance.

Autonomous load balancing anycast routing protocol for wireless mesh networks

A wireless mesh network (WMN) is expected to be a key enabler for next generation networking due to its infrastructure-less strengths such as scalability, costefficient rapid deployment, and long distance communications. To boost the strength of WMNs, it is required to balance loads among multiple gateways as well as mesh nodes. However, there have been only few practical and easily-implementable solutions for load balancing of WMNs. In this paper, we propose a distributed autonomous load balancing routing mechanism for anycast WMNs where most traffic flows are for the Internet access through any mesh gateways. Without flooding of control messages, our protocol finds optimized paths implicitly considering geographical distance and a congestion degree based on analogy of physics theory, Poissons equation and by use of a distributed form of a finite element method. Through simulations, we assess the performance of our protocol compared with the anycast modifications of traditional shortest-path routing and geographic routing under dynamically varying network scenarios.

Availability analysis and optimization of HSR-based ethernet mesh networks

The IEC 62439-3 high-availability seamless redundancy (HSR) protocol can achieve maximal network availability by means of simultaneously transmitting duplicate frames over disjoint paths for a full utilization of inherent network redundancies. Deploying HSR in mesh networks, however, requires significant design practices to avoid an unnecessary network cost spending. This paper investigates the trade-off between the redundancy investment and the realization of the network availability demanded by the customer. In this regard, we propose an optimized design scheme for cost-effective resilient HSR mesh networks and develop an enumeration based algorithm exploiting the concept of meta-mesh graph reduction. The NP-hardness of the problem, however, limits the applicability of enumeration based approaches to only small size networks. Hence, a greedy-based heuristic algorithm is proposed to overcome the computation complexity. The simulation results show that our heuristic algorithm achieves a performance comparable to the optimal solutions.

Optimal Multicast Control for Simple Network Coding

We propose a network coding strategy for multicast applications called the simple network coding scheme, which takes network coding chances raised among adjacent nodes. The proposed scheme incorporates both intrasession and intersession network coding strategies and effectively improves multicast throughput. We characterize the capacity region of the proposed scheme and derive an optimal control algorithm for the proposed scheme. We perform a complexity analysis for the proposed control algorithm and provide some insights into its practical implementation. For a comparison, we also formulate the capacity region of conventional multicast schemes and provide performance evaluation using a linear programming solver. In empirical analyses, we investigate how the proposed scheme improves multicast throughput gains from various perspectives (i.e, the number of flows, the number of network coded packets, and split-multicast) and find out that most of the gains can be achieved by simple pairwise network coding with non-split-multicast. We observe dramatic throughput gains up to 75% beyond the conventional schemes on random topologies with ten nodes.

Autonomous load balancing anycast routing for wireless mesh networks: VoIP call support

Voice over IP (VoIP) over a wireless mesh network (WMN) is a killer application candidate of the next generation services over wireless and mobile network infrastructure. Yet, the routing and transport efficiencies in consideration of specific attributes of WMNs have been little emphasized. Distinctively from conventional networks, the major traffic pattern of WMNs is anycast (one-to-one-of-many). To fully utilize the service aspects of WMNs, load balancing and scalability should simultaneously be supported. For VoIP, one challenge is to maintain the perceived quality depending on both loss and delay. In this paper, we assess autonomous load balancing anycast routing regarding VoIP supportability. The protocol is based on physics analogy and a distributed algorithm. We compare the protocol with shortest-path routing and back-pressure routing via simulations. Simulation results exhibit that autonomous load balancing of the protocol efficiently supports voice calls to guarantee the certain level of quality.