Single point of failure

Architecture. Many common practices negatively affect SCADA security. For example, while it is convenient to use SCADA capabilities for other purposes such as fire and security systems, these practices create single points of failure. Also, the connection of SCADA networks to other automation systems and business networks introduces multiple entry points for potential adversaries. 

Any location that has a connection to the SCADA network is a target, especially unmanned or unguarded remote sites. Conduct a physical security survey and inventory access points at each facility that has a connection to the SCADA system. Identify and assess any source of information including remote telephone/ computer network/fiber optic cables that could be tapped radio and microwave links that are exploitable computer terminals that could be accessed and wireless local area network access points. Identify and eliminate single points of failure. The security of the site must be adequate to detect or prevent unauthorized access. Do not allow live network access points at remote, unguarded sites simply for convenience. 

A more robust solution is to introduce a load balancer between die clients and a farm of identical middle tier servers. The load balancer routes requests to one of the middle tier servers based on the load and netweork topology. If one middle tier server fails, it can reroute the request to another to prevent single point of failure (fail-over). This architecture requires that the servers in the middle tier farm synchronize user sessions with each other in case one has to take over a client from another. 

D. The hub provides the central connecting device in a star topology. All workstations must, therefore, connect to the hub in order to gain access to each other or any other resources present on the network. The one disadvantage of this is that the hub becomes a single point of failure. If the hub stops working, no one connected to the hub has network connectivity. 

The two-phase commit protocol has some limitations. One is the performance overhead that is introduced by aU the message exchanges. If the remote sites are distributed over a wide area network, the response time could suffer further. The two-phase commit is also very sensitive to the availability of aU sites at the time of update, and even a single point of failure could jeopardize the entire transaction. Therefore, decisions should be based on the business needs and the trade-off between the cost of maintaining the data on a single site and the cost of the two-phase commit when data are distributed at remote sites. 

Sound architectural design is essential in eliminating single points of failure and in providing an appropriate level of redundancy. 

The system architecture has a previously unidentified single point of failure... 

When clinicians rely on systems without access to alternative sources of information this can result in a single point of failure for the delivery of safe cUiueal care. 

Within aviation, analyzing the exact causes of accidents and incidents is a nontrivial task. Even if detailed flight data from the black box are available, it is usually still difficult to come up with a clear analysis, for the simple reason that the causes of incidents cannot be attributed to a single point of failure of one individual entity. Instead, most incidents in aviation are found to be caused by a complex interplay of processes at various levels of the socio-technical system, involving pilots, air traffic controllers, technical systems, and their interaction. For example the famous accident in 2009 of Air France Flight 447 is stiU under investigation and seems to have been the consequence of a rare combination of factors. On May 31, 2009, this flight disappeared... 

Relief valve lines too small to relieve pressure fast enough This is in effect a single point of failure for the emergency relief system... 

In 2004, Selker and Goler report on The SAVE system — secure architecture for voting electronically[Sl] This voting architecture provides a means to vote over open networks in a way that is reliable, secure, and private. Their proposal is based on demonstrating that — through n-version redundancy techniques — there is no single point of failure in their system. However, their proposed architecture is not robust against denial-of-service attacks. 

Finally, when allocating risk reduction, it is important to remember that one operator equals one response. Multiple alarms generally do not yield higher performance because the operator is the single point of failure for the necessary response. If the team has allocated risk reduction to an operator action in the BPCS layer, additional risk reduction should not be taken for an operator action allocated to the SIS layer for the same hazard scenario unless a detailed analysis is performed. When examining the overall risk reduotion that can be provided by the alarms, it is important to recognize the potential for common-mode failure due to operator or procedural error. 

DST—Distributed spanning trees based routing protocol (Radhakrishnan, 1999). In DST, all nodes are grouped into trees, within which a node becomes a routing node or an internal node. The root, which is also a node, controls the structure of the tree. This may become a disadvantage of DST for the root node creates a single point of failure. 

In a diverse system of systems such as exists within the Trust, as a group of hospitals, the importance of the network has become ever greater. For some years, a policy of improving the capacity and resilience of the network has had many benefits. Technological diversity, physical separation and avoidance of single points of failure have all been developed as guiding principles. The performance of network components is kept under review, with less reliable components being updated as needed. 

Single points of failure one malfunctioning device causes an SIF failure. 

High availability, no single point of failure When a system experiences a failure, it should continue operation without interruption during repair, that is, failure recovery. 

No single point of failure to interrupt continuous plant operation... 

At Johnson, safety programs are centralized under a Director who oversees five divisions and an Independent Assessment Office... the Space Shuttle Division Chief is empowered to represent the Center, the Shuttle Program, and NASA Headquarters Safety and Mission Assurance at critical junctures in the safety process. This position therefore represents a critical node in NASA s Safety and Mission Assurance architecture that seems to the Board to be plagued with conflict of interest. It is a single point of failure without any checks and balances. 

Single point of failure condition Has it been identified - Record. ... 

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