Topology Discovery Research Articles

Hierarchical Distributed Orchestration Framework for Multi-Domain SDTNs

This paper presents an overarching orchestration architecture that combines hierarchical orchestration and distributed orchestration architectures for multicarrier and multi-domain software-defined transport networks (SDTNs). The objective of this study is to investigate how to combine the hierarchical topology discovery architecture and the distributed per-domain provisioning architecture, in which a set of child orchestrators (COs) enables end-to-end provisioning services in peer-to-peer environments while a parent orchestrator (PO) as well as the COs disseminate abstract inter- and intra-domain topological information between the PO and the COs. To analyze the proposed architecture, a hierarchical distributed orchestration framework was implemented and evaluated. The experimental and mathematical results demonstrate that the proposed architecture has advantages that enable fast dissemination of the abstract inter-domain topological information and evenly distribute the path computation and provisioning burden among all COs, thereby resulting in high scalability and efficiency for the orchestration of heterogeneous SDTN controllers and transport network infrastructure.

Efficient topology discovery algorithm for software‐defined networks

Software-defined networking (SDN) already has an established presence in the networking industry as an emerging paradigm for designing network architectures, decoupling the control from the forwarding plane and offering a centralised way of network management. Cloud and enterprise infrastructure engineers have already adopted such techniques for building up their environments, deliberating the cost and flexibility advantages gained from this technology. However, smaller companies may choose a progressive replacement of their equipment due to operational and budget constraints. Hence, mixing equipment could lead up to hybrid SDN environments making network management even more complex. In this study, an event-based generic topology discovery algorithm, capable of providing an efficient packet discovery mechanism using existing protocols in SDN networks, is proposed. For testing and evaluation purposes, address resolution protocol and link layer discovery protocol are being used to extract the information needed and reconstruct the topology to the controller. Implementation is accomplished using Internet Engineering Task Force's ForCES framework.

IoT환경에서의 부하 균형을 이룬 네트워크 토폴로지 탐색

IoT환경에서의 부하 균형을 이룬 네트워크 토폴로지 탐색

Fuzzy topology discovery protocol for SDN-based wireless sensor networks

The growing trend in pervasive systems forces traditional wireless sensor networks to deal with new challenges, such as dynamic application requirements and heterogeneous networks. One of the latest paradigms in this area is software defined wireless sensor network. According to the paradigm, the networks take care of managing topological information and forwarding decisions using a bipartite architecture in which a control plane decides the forwarding policies and the data plane (i.e. ordinary sensor nodes) executes them. Unfortunately, in highly dynamic networks, this approach generates an overhead of control packet exchange between the ordinary nodes and the control plane, that leads to additional energy consumptions. This paper proposes a fuzzy logic based solution, called Fuzzy Topology Discovery Protocol (FTDP), to improve the efficiency of software defined wireless sensor networks. This work is designed according to the Software Defined Networking solution for WIreless SEnsor networks (SDN-WISE), which is an open source solution for software defined wireless sensor networks. The proposed work is one of the first attempts to use fuzzy theory in software defined based wireless sensor networks. The simulation results show that our approach can increase the lifetime of the network by 45% and decreases the packet loss ratio by 50% compared to the basic SDN-WISE solution.

AS-Level Topology Discovery: Measurement strategies tailored for crowdsourcing systems

The rise of crowdsourcing systems for network measurements fosters the design of new measurement paradigms to cope with the limitations of such systems, i.e. devices with scarce resources. In this paper we address the problem of running active measurements for discovering the Internet topology at the autonomous system level of abstraction with crowdsourcing systems. We show how to obtain meaningful results with an extremely low number of measurements. We devise two classes of measurement strategies based on different approaches: topological and historical. We experimentally validate our strategies by comparing them with measurements collected with a broad strategy by Portolan, a crowdsourcing system based on mobile devices. We show that the number of measurements can be reduced up to over 80%, at the cost of a negligible loss of useful information. We finally provide pros and cons of the two classes of strategies along with a detailed analysis of the reasons why the (small) loss of information happens.

Software-Defined Wireless Mesh Networking: Current Status and Challenges

The combination of Software-Defined Networking (SDN) and Wireless Mesh Network (WMN) is challenging due to the different natures of both concepts. SDN describes networks with homogeneous, static and centralized controlled topologies. In contrast, a WMN is characterized by a dynamic and distributed network control, and adds new challenges with respect to time-critical operation. However, SDN and WMN are both associated with decreasing the operational costs for communication networks which is especially beneficial for internet provisioning in rural areas. This work surveys the current status for Software-Defined Wireless Mesh Networking. Besides a general overview in the domain of wireless SDN, this work focuses especially on different identified aspects: representing and controlling wireless interfaces, control-plane connection and topology discovery, modulation and coding, routing and load-balancing and client handling. A complete overview of surveyed solutions, open issues and new research directions is provided with regard to each aspect.

Topology Discovery Protocol for Train Inauguration in Wireless Train Networks

With the recent rapid improvement of wireless communication technology, wireless network gains increasing interest as a train backbone in order to provide the passenger service as well as the original real-time control duties. To use the wireless network as a train backbone, however, the existing standard protocol, IEC Std. 61375 Train Communication Network(TCN), needs to be modified to reflect the wireless-specific characteristics because it was originally designed for the wired network such as switched Ethernet. The train topology discovery protocol(TTDP) that provides automatic network reconfiguration is one of the key TCN protocols to be modified to support a wireless train bus. This paper proposes a modified topology discovery protocol that can be used for a train-wide wireless LAN. Proposed protocol finds the bus topology based on the radio signal strength with maintaining the existing standards and controls the transmit signal power to avoid overhearing problem in wireless network. The time bound to build network topology using the proposed protocol is also estimated by computer simulation.

Network Topology Discovery Technology in Smart Substation

Topology discovery technology is the basis of realizing the management of communication network management in smart substation, and the working principle and working flow of LLDP are described in detail, and its features make it suitable for smart substation network. Through reading the lldpRem Table in switches, all the switch nodes in the whole network can be deeply searched. According this method, a specific implementation case is given. By reading the MAC address table of switch, the connection position of the terminal device on the switch is acquired, also the solution of the incompleteness and aging of the MAC address table is provided. Then, an entire network topology containing every switch port can be constructed.

Hierarchical Distributed Topology Discovery Protocol for Multi-Domain SDN Networks

This letter presents a hierarchical distributed topology discovery protocol on the use of hierarchical path computation elements (PCEs) for orchestrating multi-domain software-defined networking. The challenge of this protocol is how child PCEs can maintain an abstract inter-domain topology while preserving intra-domain confidential information in a hierarchical PCE-based orchestration architecture. The experimental results show that the proposed protocol evenly distributes path computation burden among all child PCEs compared with the hierarchical PCE approach. The proposed protocol considerably reduces the provisioning delay compared with the distributed approach while preserving confidential intra-domain information.

FACT: A Framework for Authentication in Cloud-Based IP Traceback

IP traceback plays an important role in cyber investigation processes, where the sources and the traversed paths of packets need to be identified. It has a wide range of applications, including network forensics, security auditing, network fault diagnosis, and performance testing. Despite a plethora of research on IP traceback, the Internet is yet to see a large-scale practical deployment of traceback. Some of the major challenges that still impede an Internet-scale traceback solution are, concern of disclosing Internet Service Provider (ISP’s) internal network topologies (in other words, concern of privacy leak), poor incremental deployment, and lack of incentives for ISPs to provide traceback services. In this paper, we argue that cloud services offer better options for the practical deployment of an IP traceback system. We first present a novel cloud-based traceback architecture, which possesses several favorable properties encouraging ISPs to deploy traceback services on their networks. While this makes the traceback service more accessible, regulating access to traceback service in a cloud-based architecture becomes an important issue. Consequently, we address the access control problem in cloud-based traceback. Our design objective is to prevent illegitimate users from requesting traceback information for malicious intentions (such as ISPs topology discovery). To this end, we propose a temporal token-based authentication framework, called FACT, for authenticating traceback service queries. FACT embeds temporal access tokens in traffic flows, and then delivers them to end-hosts in an efficient manner. The proposed solution ensures that the entity requesting for traceback service is an actual recipient of the packets to be traced. Finally, we analyze and validate the proposed design using real-world Internet data sets.

Analyzing the robustness of an array of wireless access points to mobile jammers

We present an approach for measuring the vulnerability of a wireless network. Our metric, n-Robustness, measures the change in a network’s total signal strength resulting from the optimal placement of n jammers by an attacker. Toward this end, we develop a multi-period mixed-integer programming interdiction model that determines the movement of n jammers over a time horizon so as to minimize the total signal strength of users during a sustained jamming attack. We compared several solution approaches for solving our model including a Lagrangian relaxation heuristic, a genetic algorithm, and a stage decomposition heuristic. We tested our approach on a wireless trace dataset developed as part of the Wireless Topology Discovery project at the University of California San Diego. We found that the Lagrangian approach, which performed best overall, finds a close-to-optimal solution while requiring much less time than solving the MIP directly. We then illustrate the behavior of our model on a small example taken from the dataset as well as a set of experiments. Through our experiments we conclude that the total signal power follows a sigmoid curve as we increase the number of jammers and access points. We also found that increasing access points only improves network robustness initially; after that the benefit levels off. In addition, we found that the problem instances we considered have an n-Robustness of between 39 and 69%, indicating that the value of the model parameters (e.g., number of jammers, number of time periods) has an effect on robustness.

SOUNET: Self-Organized Underwater Wireless Sensor Network.

In this paper, we propose an underwater wireless sensor network (UWSN) named SOUNET where sensor nodes form and maintain a tree-topological network for data gathering in a self-organized manner. After network topology discovery via packet flooding, the sensor nodes consistently update their parent node to ensure the best connectivity by referring to the time-varying neighbor tables. Such a persistent and self-adaptive method leads to high network connectivity without any centralized control, even when sensor nodes are added or unexpectedly lost. Furthermore, malfunctions that frequently happen in self-organized networks such as node isolation and closed loop are resolved in a simple way. Simulation results show that SOUNET outperforms other conventional schemes in terms of network connectivity, packet delivery ratio (PDR), and energy consumption throughout the network. In addition, we performed an experiment at the Gyeongcheon Lake in Korea using commercial underwater modems to verify that SOUNET works well in a real environment.

Topology Discovery in Software Defined Networks: Threats, Taxonomy, and State-of-the-Art

The fundamental role of the software defined networks (SDNs) is to decouple the data plane from the control plane, thus providing a logically centralized visibility of the entire network to the controller. This enables the applications to innovate through network programmability. To establish a centralized visibility, a controller is required to discover a network topology of the entire SDN infrastructure. However, discovering a network topology is challenging due to: 1) the frequent migration of the virtual machines in the data centers; 2) lack of authentication mechanisms; 3) scarcity of the SDN standards; and 4) integration of security mechanisms for the topology discovery. To this end, in this paper, we present a comprehensive survey of the topology discovery and the associated security implications in SDNs. This survey provides discussions related to the possible threats relevant to each layer of the SDN architecture, highlights the role of the topology discovery in the traditional network and SDN, presents a thematic taxonomy of topology discovery in SDN, and provides insights into the potential threats to the topology discovery along with its state-of-the-art solutions in SDN. Finally, this survey also presents future challenges and research directions in the field of SDN topology discovery.

A Low-Cost Measurement Framework in Software Defined Networks

Software Defined Network (SDN) makes network management more flexible by separating control plane and data plane, centralized control and being programmable. Although, network measurement still remains in primary stage in SDN, it has become an essential research field in SDN management. In this context, this paper presents a low-cost high-accuracy measurement framework to support various network measurement tasks, such as throughput, delay and packet loss rate. In this framework, we only measure per-flow edge switches (the first and the last switches). In addition, a new adaptive sampling algorithm is proposed to significantly improve measurement accuracy and decrease network overhead. Meanwhile, we consider a low-cost topology discovery approach into our framework instead of topology discovery currently implemented by SDN controller frameworks. In order to improve the accuracy of delay, we also join a time threshold value to adjust the time delay. Furthermore, we consider and analyze the balance between measurement overhead and accuracy in several aspects. Last, we utilize POX controller to implement the proposed measurement framework. The effectiveness of our solution is demonstrated through simulations in Mininet and Matlab.

Discovering the Network Topology: An Efficient Approach for SDN

Network topology is a physical description of the overall resources in the network. Collecting this information using efficient mechanisms becomes a critical task for important network functions such as routing, network management, quality of service (QoS), among many others. Recent technologies like Software-Defined Networks (SDN) have emerged as promising approaches for managing the next generation networks. In order to ensure a proficient topology discovery service in SDN, we propose a simple agents-based mechanism. This mechanism improves the overall efficiency of the topology discovery process. In this paper, an algorithm for a novel Topology Discovery Protocol (SD-TDP) is described. This protocol will be implemented in each switch through a software agent. Thus, this approach will provide a distributed solution to solve the problem of network topology discovery in a more simple and efficient way.

An Algorithm of Physical Network Topology Discovery in Multi-VLANs

The most recent physical topology discovery knowledge of the Ethernet network is the key to network management tasks. Virtual LANs (VLANs) allow network managers to completely break the correlation between the logical and physical network by grouping the interfaces of the same network elements into different subnets. An efficient and general algorithm for discovering physical network topology across multi-VLANs is very necessary. Our topology discovery algorithms are simple for VLANs if we know the VLANs interface groups. The algorithm based on MIB information of SNMP standard is widely supplied by modern IP network elements and does not need modify the operating system software running on hosts or elements. The experimental results prove the correctness of the algorithm and the sufficient and necessary conditions for the uniqueness of the restored topology.

Control plane solutions for sliceable bandwidth transceiver configuration in flexi-grid optical networks

In EONs, the establishment of flexi-grid optical connections requires configuring both BVTs and bandwidth variable cross-connects. Such configuration has to be performed through proper control plane architecture and extensions, accounting for the client signal data rate, the required modulation format, the adopted forwarding error correction mechanisms, the number of carriers, and the required spectrum resources. Nowadays, two candidate control plane architectures with similar functions (like endpoint and node addressing, automatic topology discovery, network abstraction, path computation, and connection provisioning) can be adopted: distributed GMPLS - with optional PCE and instantiation/modification - and a control plane based on SDN with a logically centralized controller and an open protocol such as OpenFlow. In this work, by relying on the data modeling of 1 Tb/s SBVTs, we aim to design and provide feasible control plane enhancements for both GMPLS/PCE and SDN/OpenFlow architectures to automatically configure endpoint SBVTs while dynamically establishing end-to-end connections in EONs. Such extensions, successfully validated in experimental scenarios, are qualitatively compared to ease eventual EON operator selection.

Topology Discovery for Linear Wireless Networks With Application to Train Backbone Inauguration

A train backbone network consists of a sequence of nodes arranged in a linear topology. A key step that enables communication in such a network is that of topology discovery, or train inauguration, whereby nodes learn in a distributed fashion the physical topology of the backbone network. While the current standard for train inauguration assumes wired links between adjacent backbone nodes, this work investigates the more challenging scenario in which the nodes communicate wirelessly. The key motivations for this desired switch from wired topology discovery to wireless one are the flexibility and capability for expansion and upgrading of a wireless backbone. The implementation of topology discovery over wireless channels is made difficult by the broadcast nature of the wireless medium, and by fading and interference. A novel topology discovery protocol is proposed that overcomes these issues and requires relatively minor changes to the wired standard. The protocol is shown via analysis and numerical results to be robust to the impairments caused by the wireless channel including interference from other trains.

Design and Implementation of a Stateful PCE-Based Unified Control and Management Framework for Carrier-Grade MPLS-TP Networks

This paper presents the design and evaluation of a generalized topology discovery, operational monitoring, and provisioning (G-TOP) controller for a carrier-grade transport network. The G-TOP controller is a vendor-specific extension of the stateful PCE that integrates network topology discovery, path computation, and provisioning functions, but decouples the switch specific management framework. The G-TOP protocol enables the G-TOP controller to collect topology information, set up LSPs, and monitor state both from and to the management framework in a unified way. To validate the feasibility of the proposed framework, the author implemented a testbed using a multi-protocol label switching transport profile (MPLS-TP) switches and performed experimental testing. The experimental results show that the centralized control framework reduces provisioning time by approximately 68 ms and the autonomous management framework reduces fault recovery time by approximately 27 ms, while reducing the traffic load on the controller by several orders of magnitude compared to the OpenFlow approach.

Multipartner Demonstration of BGP-LS-Enabled Multidomain EON Control and Instantiation With H-PCE [Invited

The control of multidomain elastic optical networks (EONs) is possible by combining Hierarchical Path Computation Element (H-PCE)-based computation, Border Gateway Protocol with Extensions for Traffic Engineering Link State Information (BGP-LS) topology discovery, remote instantiation via Path Computation Element Communication Protocol (PCEP), and signaling via Resource Reservation Protocol with Extensions for Traffic Engineering (RSVP-TE). Two evolutionary architectures are considered, one based on stateless H-PCE, PCEP instantiation, and end-to-end RSVP-TE signaling (SL-E2E), and a second one based on stateful active H-PCE with perdomain instantiation and stitching. This paper presents the first multiplatform demonstration that fully validates both control architectures achieving multiprotocol interoperability. SL-E2E leads to slightly faster provisioning but needs to keep the state of the stitching of the end-to-end label-switched paths in the parent PCE.