Group Communication System (GCS) is an important building block for reliable, fault-tolerant distributed applications. Due to highly variable and unpredictable latency in WANs, GCS needs to cope with frequent membersh...
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ISBN:
(纸本)0769509754
Group Communication System (GCS) is an important building block for reliable, fault-tolerant distributed applications. Due to highly variable and unpredictable latency in WANs, GCS needs to cope with frequent membership, changes. It results in diminishing the scalability of GCS. In this paper we propose a new scheme that improves the scalability of group membership service for WANs by exploring dedicated membership sewers configured into multiple layers and reaching global agreement on the view through layered servers. It improves the scalability of a process group of N member processes front O(N-2) to O(N-3) with three layers, where N is the number of processes in the group. Computer simulation verifies that the proposed scheme requires much smaller number of message exchanges for reaching an agreement on a next view and does that much quicker. In addition, the proposed scheme pl events applications from being blocked until reaching the final view agreement if the applications permit temporary inconsistency.
Replication is often used to provide users of distributed virtual environments with high-performance interactions. Concurrency control is required to avoid inconsistent views among replicas due to multiple concurrent ...
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Replication is often used to provide users of distributed virtual environments with high-performance interactions. Concurrency control is required to avoid inconsistent views among replicas due to multiple concurrent updates. G. Lann has developed a prediction-based concurrency control scheme to allow real-time interactions for users and to eliminate the need for repairs. The existing scheme does not scale in terms of delivering ownership on time as the number of users increases. In this paper, we propose a scalable prediction-based concurrency control scheme with entity-centric multicasting: only the users surrounding a target entity multicast the ownership requests, by using the multicast address assigned to the entity. The experimental results and analysis reported in this paper show that the proposed scheme achieves the benefits of prediction-based concurrency control with efficiency and scalability for large distributed virtual environments.
Group Communication System (GCS) is an important building block for reliable, fault-tolerant distributed applications. Due to highly variable and unpredictable latency in WANs, GCS needs to cope with frequent membersh...
详细信息
Group Communication System (GCS) is an important building block for reliable, fault-tolerant distributed applications. Due to highly variable and unpredictable latency in WANs, GCS needs to cope with frequent membership changes. It results in diminishing the scalability of GCS. In this paper we propose a new scheme that improves the scalability of group membership service for WANs by exploiting dedicated membership servers configured into multiple layers and reaching global agreement on the view through layered servers. It improves the scalability of a process group of N member processes from O(N/sup 2/) to O(N/sup 3/) with three layers, where N is the number of processes in the group. Computer simulation verifies that the proposed scheme requires much smaller number of message exchanges for reaching an agreement on a next view and does that much quicker. In addition, the proposed scheme prevents applications from being blocked until reaching the final view agreement if the applications permit temporary inconsistency.
In a pervasive computing environment, users interact with many smart devices or service providers (SPs) to obtain some useful services from them. These SPs can be either genuine or malicious. As a result, users privac...
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In a pervasive computing environment, users interact with many smart devices or service providers (SPs) to obtain some useful services from them. These SPs can be either genuine or malicious. As a result, users privacy is at a greater risk, as they are prone to revealing their location, identity and transactions information to such SPs. On the other hand, user authentication is also required for SPs to provide service access control to only authorized users. In order to protect users privacy, they must be allowed to have anonymous interactions with SPs. But, authenticating and authorizing an anonymous user becomes a challenging task. In this paper, we propose a simple and efficient scheme that allows users to anonymously interact with SPs and the SPs can effectively authenticate and authorize the users based on the anonymous information submitted by the users.
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