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2021-01-11
Malik, A., Fréin, R. de, Al-Zeyadi, M., Andreu-Perez, J..  2020.  Intelligent SDN Traffic Classification Using Deep Learning: Deep-SDN. 2020 2nd International Conference on Computer Communication and the Internet (ICCCI). :184–189.
Accurate traffic classification is fundamentally important for various network activities such as fine-grained network management and resource utilisation. Port-based approaches, deep packet inspection and machine learning are widely used techniques to classify and analyze network traffic flows. However, over the past several years, the growth of Internet traffic has been explosive due to the greatly increased number of Internet users. Therefore, both port-based and deep packet inspection approaches have become inefficient due to the exponential growth of the Internet applications that incurs high computational cost. The emerging paradigm of software-defined networking has reshaped the network architecture by detaching the control plane from the data plane to result in a centralised network controller that maintains a global view over the whole network on its domain. In this paper, we propose a new deep learning model for software-defined networks that can accurately identify a wide range of traffic applications in a short time, called Deep-SDN. The performance of the proposed model was compared against the state-of-the-art and better results were reported in terms of accuracy, precision, recall, and f-measure. It has been found that 96% as an overall accuracy can be achieved with the proposed model. Based on the obtained results, some further directions are suggested towards achieving further advances in this research area.
Khandait, P., Hubballi, N., Mazumdar, B..  2020.  Efficient Keyword Matching for Deep Packet Inspection based Network Traffic Classification. 2020 International Conference on COMmunication Systems NETworkS (COMSNETS). :567–570.
Network traffic classification has a range of applications in network management including QoS and security monitoring. Deep Packet Inspection (DPI) is one of the effective method used for traffic classification. DPI is computationally expensive operation involving string matching between payload and application signatures. Existing traffic classification techniques perform multiple scans of payload to classify the application flows - first scan to extract the words and the second scan to match the words with application signatures. In this paper we propose an approach which can classify network flows with single scan of flow payloads using a heuristic method to achieve a sub-linear search complexity. The idea is to scan few initial bytes of payload and determine potential application signature(s) for subsequent signature matching. We perform experiments with a large dataset containing 171873 network flows and show that it has a good classification accuracy of 98%.
2020-11-17
Poltronieri, F., Sadler, L., Benincasa, G., Gregory, T., Harrell, J. M., Metu, S., Moulton, C..  2018.  Enabling Efficient and Interoperable Control of IoBT Devices in a Multi-Force Environment. MILCOM 2018 - 2018 IEEE Military Communications Conference (MILCOM). :757—762.

Efficient application of Internet of Battlefield Things (IoBT) technology on the battlefield calls for innovative solutions to control and manage the deluge of heterogeneous IoBT devices. This paper presents an innovative paradigm to address heterogeneity in controlling IoBT and IoT devices, enabling multi-force cooperation in challenging battlefield scenarios.

2020-08-28
Ferreira, P.M.F.M., Orvalho, J.M., Boavida, F..  2005.  Large Scale Mobile and Pervasive Augmented Reality Games. EUROCON 2005 - The International Conference on "Computer as a Tool". 2:1775—1778.
Ubiquitous or pervasive computing is a new kind of computing, where specialized elements of hardware and software will have such high level of deployment that their use will be fully integrated with the environment. Augmented reality extends reality with virtual elements but tries to place the computer in a relatively unobtrusive, assistive role. To our knowledge, there is no specialized network middleware solution for large-scale mobile and pervasive augmented reality games. We present a work that focus on the creation of such network middleware for mobile and pervasive entertainment, applied to the area of large scale augmented reality games. In, this context, mechanisms are being studied, proposed and evaluated to deal with issues such as scalability, multimedia data heterogeneity, data distribution and replication, consistency, security, geospatial location and orientation, mobility, quality of service, management of networks and services, discovery, ad-hoc networking and dynamic configuration
2020-05-04
Zhou, Zichao, An, Changqing, Yang, Jiahai.  2018.  A Programmable Network Management Architecture for Address Driven Network. 2018 10th International Conference on Communications, Circuits and Systems (ICCCAS). :199–206.
The operation and management of network is facing increasing complexities brought by the evolution of network protocols and the demands of rapid service delivery. In this paper, we propose a programmable network management architecture, which manages network based on NETCONF protocol and provides REST APIs to upper layer so that further programming can be done based on the APIs to implement flexible management. Functions of devices can be modeled based on YANG language, and the models can be translated into REST APIs. We apply it to the management of ADN (Address Driven Network), an innovative network architecture proposed by Tsinghua University to inhibit IP spoofing, improve network security and provide high service quality. We model the functions of ADN based on YANG language, and implement the network management functions based on the REST APIs. We deploy and evaluate it in a laboratory environment. Test result shows that the programmable network management architecture is flexible to implement management for new network services.
2020-02-18
Yu, Bong-yeol, Yang, Gyeongsik, Jin, Heesang, Yoo, Chuck.  2019.  White Visor: Support of White-Box Switch in SDN-Based Network Hypervisor. 2019 International Conference on Information Networking (ICOIN). :242–247.

Network virtualization is a fundamental technology for datacenters and upcoming wireless communications (e.g., 5G). It takes advantage of software-defined networking (SDN) that provides efficient network management by converting networking fabrics into SDN-capable devices. Moreover, white-box switches, which provide flexible and fast packet processing, are broadly deployed in commercial datacenters. A white-box switch requires a specific and restricted packet processing pipeline; however, to date, there has been no SDN-based network hypervisor that can support the pipeline of white-box switches. Therefore, in this paper, we propose WhiteVisor: a network hypervisor which can support the physical network composed of white-box switches. WhiteVisor converts a flow rule from the virtual network into a packet processing pipeline compatible with the white-box switch. We implement the prototype herein and show its feasibility and effectiveness with pipeline conversion and overhead.

2020-02-10
Chen, Yige, Zang, Tianning, Zhang, Yongzheng, Zhou, Yuan, Wang, Yipeng.  2019.  Rethinking Encrypted Traffic Classification: A Multi-Attribute Associated Fingerprint Approach. 2019 IEEE 27th International Conference on Network Protocols (ICNP). :1–11.

With the unprecedented prevalence of mobile network applications, cryptographic protocols, such as the Secure Socket Layer/Transport Layer Security (SSL/TLS), are widely used in mobile network applications for communication security. The proven methods for encrypted video stream classification or encrypted protocol detection are unsuitable for the SSL/TLS traffic. Consequently, application-level traffic classification based networking and security services are facing severe challenges in effectiveness. Existing encrypted traffic classification methods exhibit unsatisfying accuracy for applications with similar state characteristics. In this paper, we propose a multiple-attribute-based encrypted traffic classification system named Multi-Attribute Associated Fingerprints (MAAF). We develop MAAF based on the two key insights that the DNS traces generated during the application runtime contain classification guidance information and that the handshake certificates in the encrypted flows can provide classification clues. Apart from the exploitation of key insights, MAAF employs the context of the encrypted traffic to overcome the attribute-lacking problem during the classification. Our experimental results demonstrate that MAAF achieves 98.69% accuracy on the real-world traceset that consists of 16 applications, supports the early prediction, and is robust to the scale of the training traceset. Besides, MAAF is superior to the state-of-the-art methods in terms of both accuracy and robustness.

2020-01-20
Warabino, Takayuki, Suzuki, Yusuke, Miyazawa, Masanori.  2019.  ROS-based Robot Development Toward Fully Automated Network Management. 2019 20th Asia-Pacific Network Operations and Management Symposium (APNOMS). :1–4.

While the introduction of the softwarelization technologies such as SDN and NFV transfers main focus of network management from hardware to software, the network operators still have to care for a lot of network and computing equipment located in the network center. Toward fully automated network management, we believe that robotic approach will be significant, meaning that robot will care for the physical equipment on behalf of human. This paper explains our experience and insight gained throughout development of a network management robot. We utilize ROS(Robot Operating System) which is a powerful platform for robot development and secures the ease of development and expandability. Our roadmap of the network management robot is also shown as well as three use cases such as environmental monitoring, operator assistance and autonomous maintenance of the equipment. Finally, the paper briefly explains experimental results conducted in a commercial network center.

2020-01-13
Lipps, Christoph, Krummacker, Dennis, Schotten, Hans Dieter.  2019.  Securing Industrial Wireless Networks: Enhancing SDN with PhySec. 2019 Conference on Next Generation Computing Applications (NextComp). :1–7.
The requirements regarding network management defined by the continuously rising amount of interconnected devices in the industrial landscape turns it into an increasingly complex task. Associated by the fusion of technologies up to Cyber-Physical Production Systems (CPPS) and the Industrial Internet of Things (IIoT) with its multitude of communicating sensors and actuators new demands arise. In particular, the driving forces of this development, mobility and flexibility, are affecting today's networks. However, it is precisely these wireless solutions, as enabler for this advancement, that create new attack vectors and cyber-security threats. Furthermore, many cryptographic procedures, intended to secure the networks, require additional overhead, which is limiting the transmission bandwidth and speed as well. For this reason, new and efficient solutions must be developed and applied, in order to secure the existing, as well as the future, industrial communication networks. This work proposes a conceptual approach, consisting of a combination of Software-Defined Networking (SDN) and Physical Layer Security (PhySec) to satisfy the network security requirements. Use cases are explained that demonstrate the appropriateness of the approach and it is shown that this is a easy to use and resource efficient, but nevertheless sound and secure approach.
2019-12-02
Tseng, Yuchia, Nait-Abdesselam, Farid, Khokhar, Ashfaq.  2018.  SENAD: Securing Network Application Deployment in Software Defined Networks. 2018 IEEE International Conference on Communications (ICC). :1–6.
The Software Defined Networks (SDN) paradigm, often referred to as a radical new idea in networking, promises to dramatically simplify network management by enabling innovation through network programmability. However, notable security issues, such as app-to-control threats, remain a significant concern that impedes SDN from being widely adopted. To cope with those app-to-control threats, this paper proposes a solution to securely deploy valid network applications while protecting the SDN controller against the injection of the malicious application. This problem is mitigated by proposing a novel SDN architecture, dubbed SENAD, which splits the well-known SDN controller into: (1) a data plane controller (DPC), and (2) an application plane controller (APC), to secure this latter by design. The role of the DPC is dedicated for interpreting the network rules into OpenFlow entries and maintaining the communication with the data plane. The role of the APC, however, is to provide a secured runtime for deploying the network applications, including authentication, access control, resource isolation, control, and monitoring applications. We show that this approach can easily shield against any deny of service, caused for instance by the resource exhaustion attack or the malicious command injection, that is caused by the co-existence of a malicious application on the controller's runtime. The evaluation of our architecture shows that the packet\_in messages take less than 5 ms to be delivered from the data plane to the application plane on the long range.
2019-09-09
Almohaimeed, A., Asaduzzaman, A..  2019.  A Novel Moving Target Defense Technique to Secure Communication Links in Software-Defined Networks. 2019 Fifth Conference on Mobile and Secure Services (MobiSecServ). :1–4.
Software-defined networking (SDN) is a recently developed approach to computer networking that brings a centralized orientation to network control, thereby improving network architecture and management. However, as with any communication environment that involves message transmission among users, SDN is confronted by the ongoing challenge of protecting user privacy. In this “Work in Progress (WIP)” research, we propose an SDN security model that applies the moving target defense (MTD) technique to protect communication links from sensitive data leakages. MTD is a security solution aimed at increasing complexity and uncertainty for attackers by concealing sensitive information that may serve as a gateway from which to launch different types of attacks. The proposed MTD-based security model is intended to protect user identities contained in transmitted messages in a way that prevents network intruders from identifying the real identities of senders and receivers. According to the results from preliminary experiments, the proposed MTD model has potential to protect the identities contained in transmitted messages within communication links. This work will be extended to protect sensitive data if an attacker gets access to the network device.
2019-08-05
Marchal, Xavier, Cholez, Thibault, Festor, Olivier.  2018.  $M$NDN: An Orchestrated Microservice Architecture for Named Data Networking. Proceedings of the 5th ACM Conference on Information-Centric Networking. :12-23.

As an extension of Network Function Virtualization, microservice architectures are a promising way to design future network services. At the same time, Information-Centric Networking architectures like NDN would benefit from this paradigm to offer more design choices for the network architect while facilitating the deployment and the operation of the network. We propose $μ$NDN, an orchestrated suite of microservices as an alternative way to implement NDN forwarding and support functions. We describe seven essential micro-services we developed, explain the design choices behind our solution and how it is orchestrated. We evaluate each service in isolation and the entire microservice architecture through two realistic scenarios to show its ability to react and mitigate some performance and security issues thanks to the orchestration. Our results show that $μ$NDN can replace a monolithic NDN forwarder while being more powerful and scalable.

Marchal, Xavier, Cholez, Thibault, Festor, Olivier.  2018.  ΜNDN: An Orchestrated Microservice Architecture for Named Data Networking. Proceedings of the 5th ACM Conference on Information-Centric Networking. :12–23.
As an extension of Network Function Virtualization, microservice architectures are a promising way to design future network services. At the same time, Information-Centric Networking architectures like NDN would benefit from this paradigm to offer more design choices for the network architect while facilitating the deployment and the operation of the network. We propose μNDN, an orchestrated suite of microservices as an alternative way to implement NDN forwarding and support functions. We describe seven essential micro-services we developed, explain the design choices behind our solution and how it is orchestrated. We evaluate each service in isolation and the entire microservice architecture through two realistic scenarios to show its ability to react and mitigate some performance and security issues thanks to the orchestration. Our results show that μNDN can replace a monolithic NDN forwarder while being more powerful and scalable.
2018-05-16
Guodong, T., Xi, Q., Chaowen, C..  2017.  A SDN security control forwarding mechanism based on cipher identification. 2017 IEEE 9th International Conference on Communication Software and Networks (ICCSN). :1419–1425.

SDN is a new network architecture for control and data forwarding logic separation, able to provide a high degree of openness and programmability, with many advantages not available by traditional networks. But there are still some problems unsolved, for example, it is easy to cause the controller to be attacked due to the lack of verifying the source of the packet, and the limited range of match fields cannot meet the requirement of the precise control of network services etc. Aiming at the above problems, this paper proposes a SDN network security control forwarding mechanism based on cipher identification, when packets flow into and out of the network, the forwarding device must verify their source to ensure the user's non-repudiation and the authenticity of packets. Besides administrators control the data forwarding based on cipher identification, able to form network management and control capabilities based on human, material, business flow, and provide a new method and means for the future of Internet security.

2018-05-09
Wang, Z., Hu, H., Zhang, C..  2017.  On achieving SDN controller diversity for improved network security using coloring algorithm. 2017 3rd IEEE International Conference on Computer and Communications (ICCC). :1270–1275.

The SDN (Software Defined Networking) paradigm rings flexibility to the network management and is an enabler to offer huge opportunities for network programmability. And, to solve the scalability issue raised by the centralized architecture of SDN, multi-controllers deployment (or distributed controllers system) is envisioned. In this paper, we focus on increasing the diversity of SDN control plane so as to enhance the network security. Our goal is to limit the ability of a malicious controller to compromise its neighboring controllers, and by extension, the rest of the controllers. We investigate a heterogeneous Susceptible-Infectious-Susceptible (SIS) epidemic model to evaluate the security performance and propose a coloring algorithm to increase the diversity based on community detection. And the simulation results demonstrate that our algorithm can reduce infection rate in control plane and our work shows that diversity must be introduced in network design for network security.

2018-01-23
Deb, Supratim, Ge, Zihui, Isukapalli, Sastry, Puthenpura, Sarat, Venkataraman, Shobha, Yan, He, Yates, Jennifer.  2017.  AESOP: Automatic Policy Learning for Predicting and Mitigating Network Service Impairments. Proceedings of the 23rd ACM SIGKDD International Conference on Knowledge Discovery and Data Mining. :1783–1792.

Efficient management and control of modern and next-gen networks is of paramount importance as networks have to maintain highly reliable service quality whilst supporting rapid growth in traffic demand and new application services. Rapid mitigation of network service degradations is a key factor in delivering high service quality. Automation is vital to achieving rapid mitigation of issues, particularly at the network edge where the scale and diversity is the greatest. This automation involves the rapid detection, localization and (where possible) repair of service-impacting faults and performance impairments. However, the most significant challenge here is knowing what events to detect, how to correlate events to localize an issue and what mitigation actions should be performed in response to the identified issues. These are defined as policies to systems such as ECOMP. In this paper, we present AESOP, a data-driven intelligent system to facilitate automatic learning of policies and rules for triggering remedial actions in networks. AESOP combines best operational practices (domain knowledge) with a variety of measurement data to learn and validate operational policies to mitigate service issues in networks. AESOP's design addresses the following key challenges: (i) learning from high-dimensional noisy data, (ii) capturing multiple fault models, (iii) modeling the high service-cost of false positives, and (iv) accounting for the evolving network infrastructure. We present the design of our system and show results from our ongoing experiments to show the effectiveness of our policy leaning framework.

2018-01-16
Boite, J., Nardin, P. A., Rebecchi, F., Bouet, M., Conan, V..  2017.  Statesec: Stateful monitoring for DDoS protection in software defined networks. 2017 IEEE Conference on Network Softwarization (NetSoft). :1–9.

Software-Defined Networking (SDN) allows for fast reactions to security threats by dynamically enforcing simple forwarding rules as counter-measures. However, in classic SDN all the intelligence resides at the controller, with the switches only capable of performing stateless forwarding as ruled by the controller. It follows that the controller, in addition to network management and control duties, must collect and process any piece of information required to take advanced (stateful) forwarding decisions. This threatens both to overload the controller and to congest the control channel. On the other hand, stateful SDN represents a new concept, developed both to improve reactivity and to offload the controller and the control channel by delegating local treatments to the switches. In this paper, we adopt this stateful paradigm to protect end-hosts from Distributed Denial of Service (DDoS). We propose StateSec, a novel approach based on in-switch processing capabilities to detect and mitigate DDoS attacks. StateSec monitors packets matching configurable traffic features (e.g., IP src/dst, port src/dst) without resorting to the controller. By feeding an entropy-based algorithm with such monitoring features, StateSec detects and mitigates several threats such as (D)DoS and port scans with high accuracy. We implemented StateSec and compared it with a state-of-the-art approach to monitor traffic in SDN. We show that StateSec is more efficient: it achieves very accurate detection levels, limiting at the same time the control plane overhead.

2017-11-20
Kaur, R., Singh, A., Singh, S., Sharma, S..  2016.  Security of software defined networks: Taxonomic modeling, key components and open research area. 2016 International Conference on Electrical, Electronics, and Optimization Techniques (ICEEOT). :2832–2839.

Software defined networking promises network operators to dramatically simplify network management. It provides flexibility and innovation through network programmability. With SDN, network management moves from codifying functionality in terms of low-level device configuration to building software that facilitates network management and debugging[1]. SDN provides new techniques to solve long-standing problems in networking like routing by separating the complexity of state distribution from network specification. Despite all the hype surrounding SDNs, exploiting its full potential is demanding. Security is still the major issue and a striking challenge that reduces the growth of SDNs. Moreover the introduction of various architectural components and up cycling of novel entities of SDN poses new security issues and threats. SDN is considered as major target for digital threats and cyber-attacks[2] and have more devastating effects than simple networks. Initial SDN design doesn't considered security as its part; therefore, it must be raised on the agenda. This article discusses the security solutions proposed to secure SDNs. We categorize the security solutions in the article by presenting a thematic taxonomy based on SDN architectural layers/interfaces[3], security measures and goals, simulation framework. Moreover, the literature also points out the possible attacks[2] targeting different layers/interfaces of SDNs. For securing SDNs, the potential requirements and their key enablers are also identified and presented. Also, the articles sketch the design of secure and dependable SDNs. At last, we discuss open issues and challenges of SDN security that may be rated appropriate to be handled by professionals and researchers in the future.

2017-03-07
Qazi, Zafar Ayyub, Penumarthi, Phani Krishna, Sekar, Vyas, Gopalakrishnan, Vijay, Joshi, Kaustubh, Das, Samir R..  2016.  KLEIN: A Minimally Disruptive Design for an Elastic Cellular Core. Proceedings of the Symposium on SDN Research. :2:1–2:12.

Today's cellular core, which connects the radio access network to the Internet, relies on fixed hardware appliances placed at a few dedicated locations and uses relatively static routing policies. As such, today's core design has key limitations—it induces inefficient provisioning tradeoffs and is poorly equipped to handle overload, failure scenarios, and diverse application requirements. To address these limitations, ongoing efforts envision "clean slate" solutions that depart from cellular standards and routing protocols; e.g., via programmable switches at base stations and per-flow SDN-like orchestration. The driving question of this work is to ask if a clean-slate redesign is necessary and if not, how can we design a flexible cellular core that is minimally disruptive. We propose KLEIN, a design that stays within the confines of current cellular standards and addresses the above limitations by combining network functions virtualization with smart resource management. We address key challenges w.r.t. scalability and responsiveness in realizing KLEIN via backwards-compatible orchestration mechanisms. Our evaluations through data-driven simulations and real prototype experiments using OpenAirInterface show that KLEIN can scale to billions of devices and is close to optimal for wide variety of traffic and deployment parameters.

2016-04-12
Anduo Wang, University of Illinois at Urbana-Champaign, Xueyan Mei, University of Illinois at Urbana-Champaign, Jason Croft, University of Illinois at Urbana-Champaign, Matthew Caesar, University of Illinois at Urbana-Champaign, Brighten Godfrey, University of Illinois at Urbana-Champaign.  2016.  Ravel: A Database-Defined Network. ACM SIGCOMM Symposium on Software Defined Networking Research (SOSR 2016).

SDN’s logically centralized control provides an insertion point for programming the network. While it is generally agreed that higherlevel abstractions are needed to make that programming easy, there is little consensus on what are the “right” abstractions. Indeed, as SDN moves beyond its initial specialized deployments to broader use cases, it is likely that network control applications will require diverse abstractions that evolve over time. To this end, we champion a perspective that SDN control fundamentally revolves around data representation. We discard any application-specific structure that might be outgrown by new demands. Instead, we adopt a plain data representation of the entire network — network topology, forwarding, and control applications — and seek a universal data language that allows application programmers to transform the primitive representation into any high-level representations presented to applications or network operators. Driven by this insight, we present a system, Ravel, that implements an entire SDN network control infrastructure within a standard SQL database. In Ravel, network abstractions take the form of user-defined SQL views expressed by SQL queries that can be added on the fly. A key challenge in realizing this approach is to orchestrate multiple simultaneous abstractions that collectively affect the same underlying data. To achieve this, Ravel enhances the database with novel data integration mechanisms that merge the multiple views into a coherent forwarding behavior. Moreover, Ravel is exposed to applications through the one simple, familiar and highly interoperable SQL interface. While this is an ambitious long-term goal, our prototype built on the PostgreSQL database exhibits promising performance even for large scale networks.

2015-05-06
Kuklinski, S..  2014.  Programmable management framework for evolved SDN. Network Operations and Management Symposium (NOMS), 2014 IEEE. :1-8.

In the paper a programmable management framework for SDN networks is presented. The concept is in-line with SDN philosophy - it can be programmed from scratch. The implemented management functions can be case dependent. The concept introduces a new node in the SDN architecture, namely the SDN manager. In compliance with the latest trends in network management the approach allows for embedded management of all network nodes and gradual implementation of management functions providing their code lifecycle management as well as the ability to on-the-fly code update. The described concept is a bottom-up approach, which key element is distributed execution environment (PDEE) that is based on well-established technologies like OSGI and FIPA. The described management idea has strong impact on the evolution of the SDN architecture, because the proposed distributed execution environment is a generic one, therefore it can be used not only for the management, but also for distributing of control or application functions.
 

2015-05-05
Ming Xiang, Tauch, S., Liu, W..  2014.  Dependability and Resource Optimation Analysis for Smart Grid Communication Networks. Big Data and Cloud Computing (BdCloud), 2014 IEEE Fourth International Conference on. :676-681.

Smart Grid is the trend of next generation power distribution and network management that enable a two -- way interactive communication and operation between consumers and suppliers, so as to achieve intelligent resource management and optimization. The wireless mesh network technology is a promising infrastructure solution to support these smart functionalities, while it has some inherent vulnerabilities and cyber-attack risks to be addressed. As Smart Grid is heavily relying on the underlie communication networks, which makes their security and dependability issues critical to the entire smart grid technology. Several studies have been conducted in the field of Smart Grid security, but few works were focused on the dependability and its associated resource analysis of the control center networks. In this paper, we have investigated the dependability modeling and also resource allocation in redundant communication networks by adopting two mathematical approaches, Reliability Block Diagrams (RBD) and Stochastic Petri Nets (SPNs), to analyze the dependability of control center networks in Smart Grid environment. We have applied our proposed modeling approach in an extensive case study to evaluate the availability of smart gird networks with different redundancy mechanisms. A combination of dependability models and reliability importance are used to analyze the network availability according to the most important components. We also show the variation of network availability in accordance with Mean Time to Failure (MTTF) in different network architectures.