VC merging allows VC to be mapped onto the same VC label. It provides a scalable solution for network growth. It enables features such as stream merging in MPLS and RSVP wildcard filter to be efficiently supported ove...
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VC merging allows VC to be mapped onto the same VC label. It provides a scalable solution for network growth. It enables features such as stream merging in MPLS and RSVP wildcard filter to be efficiently supported over ATM. It also plays an important role in providing multipoint-to-multipoint multicast and share-tree multicasting paradigm. VC merging involves distinguishing cells from an identical merged VC label. Various approaches have been proposed to help this identification process. However, most of them incur additional buffering, protocol overhead and/or variable delay. They make the provision of QoS difficult to achieve. In this paper, we propose a novel merge-capable scheduler to support VC merging. The proposed scheduler consists of a core scheduler and a number of sub-queue sequencers forming a 2-level hierarchical structure. Using the proposed merge-capable scheduler, we can uniquely identify incoming cells while: (1) allowing cell cut-through forwarding and interleaving; (2) maintaining per-flow QoS; and (3) requiring no additional buffer and protocol overhead. We show analytically that the scheduler can guarantee a worst-case fairness and deliver a worst-case delay bound. We further analyze the scheduler performance in term of the service received by a queue and the average queuing delay experienced by a cell. The results indicate that the amount of services is fairly distributed among merging and non-merging flows according to their reservations. Moreover, the proposed merge-capable scheduler performs equally as well as its non-merging counterpart when reservations are highly utilized, even though it may introduce a minimal additional delay when utilization is low.
This paper proposes an approach to support integrated services Internet with RSVP over ATM shortcuts (ISAC). While similar to other LP switching approaches, our work is different in three major aspects. First, it focu...
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This paper proposes an approach to support integrated services Internet with RSVP over ATM shortcuts (ISAC). While similar to other LP switching approaches, our work is different in three major aspects. First, it focuses on supporting the integrated services model whereas other approaches currently support only best effort traffic. Second, our architecture adopts RSVP as the major signaling protocol and eliminates duplication of functionality in the ATM domain. Finally, while heterogeneous multicast has not yet been supported in any other approaches, it is considered in our proposal. Our design strives to achieve three fundamental objectives: (1) ensuring compatibility with existing networking standards, applications and system software, (2) maintaining data path efficiency, and (3) assuring portability for different operating system and switch control protocol. Our proposed architecture has been proven by a prototype implementation. Its operation has been verified by demonstrating a videoconferencing application. Our prototype has also been evaluated by measuring its signaling and control latency as well as the transfer delay of the data path.
The ATM service category UBR is intended for non-real-time applications that do not require guaranteed QoS commitments. With additional, relatively inexpensive control functions such as packet discard schemes, UBR cou...
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The ATM service category UBR is intended for non-real-time applications that do not require guaranteed QoS commitments. With additional, relatively inexpensive control functions such as packet discard schemes, UBR could become a cost-effective alternative for the transmission of data traffic; offering a straightforward and flexible solution as opposed to nrt-VBR and GFR that applies stricter traffic specifications as well as ABR with its sophisticated and complex rate-control protocol. This paper presents the results obtained from a comprehensive set of experiments with TCP over UBR, comprising of measurements taken on different protocol layers. The goal is to experimentally investigate the performance of UBR to carry TCP traffic, to evaluate the performance gain achievable by packet discard schemes and TCP parameter tuning, to study the influence of the TCP implementation, and in a final step, to relate the measurements to simulation results.
In recent years, there has been a lot of interest in providing real-time multimedia services like digital audio and video over packet-switched networks such as Internet and ATM. These services require certain quality ...
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In recent years, there has been a lot of interest in providing real-time multimedia services like digital audio and video over packet-switched networks such as Internet and ATM. These services require certain quality of service (QoS) from the network. The routing algorithm should take QoS factor for an application into account while selecting the most suitable route for the application. In this paper, we introduce a new routing metric and use it with two different heuristics to compute the multicast tree for guaranteed QoS applications that need firm end-to-end delay bound. We then compare the performance of our algorithms with the other proposed QoS-based routing algorithms. Simulations were run over a number of random networks to measure the performance of different algorithms. We studied routing algorithms along with resource reservation and admission control to measure the call throughput over a number of random networks. Simulation results show that our algorithms give a much better performance in terms of call throughput over other proposed schemes like QOSPF.
The emergence of Open Systems Interconnection protocols, as specified within the U.S. Government Open Systems Interconnection Profile (GOSIP) Federal Information Processing Standard (FTPS), provides both an opportunit...
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