چکیده:
Society is growing increasingly dependent upon large-scale, highiy distributed systems that operate in unbounded open network environments. Unless safeguards are incorporated in the system, a failure of even a single component, e.g a link or a node, can significantly impact the network performance and can cause highly expensive damages. The discipl Inc of survivability attempts to ensure that network systems can deliver essential services and maintains inherent properties such as integrity, confidentiality, and performance, in the presence of attacks, failures or accidents. Optical networks based on Wavelength-Division Multiplex ing (WDM) technology can potentially transfer hundreds of gigabits of data per second in the network. WDM networks are believed to be a promising candidate to meet the explosive increase of bandwidth demand in the Internet. However, the high capacity of a link has the drawback that a failure can potentially lead to the loss of a large amount of data. This is why the survivability performance of networks is an important research issue. The objective of this paper is to answer questions like “What does survivability mean°”, “Why is it important*”, “How does it differ from fault tolerance°” and “How is it being measured*” by surveying the concepts of information and network survivability, its relation to and its distinction from dependability, fault tolerance and security. The survivability of optical networks and protection techniques in WDM networks are reviewed as an example of techniques to improve the network survivability. The problem of survivability measures from network analysis and design point of view is also presented in the paper.
خلاصه ماشینی:
The discipl Inc of survivability attempts to ensure that network systems can deliver essential services and maintains inherent properties such as integrity, confidentiality, and performance, in the presence of attacks, failures or accidents.
The objective of this paper is to answer questions like “What does survivability mean°”, “Why is it important*”, “How does it differ from fault tolerance°” and “How is it being measured*” by surveying the concepts of information and network survivability, its relation to and its distinction from dependability, fault tolerance and security.
Information and Network Survivability, Fault Tolerance, Dependability, Optical Network, WDM INTRODUCTION Since failure of information systems can cause a major loss of service, their dependability is a major concern.
Current facets of dependability, such as reliability and availability, do not address the needs of critical information systems adequately because they do not include the notion of degraded service as an explicit requirement.
Current facets of dependability, such as reliability and availability, do not address the needs of critical information systems adequately because they do not include the notion of degraded service as an explicit requirement.
Today, recovery strategies in use include the replication of critical information and services, the use of fault-tolerant designs, and a variety of backup systems for hardware and software, including maintaining master copies of critical software in isolation from the network [26].
For example, Figure 2: The survivable(View the image of this page) network analysis method a Fictional Company (FC) would be required to provide services to keep extranet customers such as the credit card companies and online stores connected at all times tor transactions to be occurred.