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An Integrated Approach for Quality of Service in Cluster Networks

Dimension Value
  • Discipline
  • Other
  • Project Working Hours
  • Not Specified
  • Research Study Hybrid Value Creation
    • Funding Institutions
    • National governmental Funding
      • Other
    • Other Funding Institutions
    • National Science Foundation
    Contact Person/s: Dr. Chitaranjan Das

    An Integrated Approach for Quality of Service in Cluster Networks ()

    With the increasing use of cluster systems for a variety of interactive applications, predictable communication performance or Quality of Service (QoS), has become a major concern. The motivation of this research was to design a cluster communication infrastructure to support different applications with varying QoS requirements. In particular, the research focused on  using the wormhole switching paradigm, which has been used in designing many commercial routers such as the Marcum's Myrinet and IBM SP2, for providing QoS guarantees. The research activities include (1) wormhole router architecture design and evaluation to provide predictable and high performance; (2) network interface and software messaging layer support to inject/eject traffic into/from the network as per the QoS requirements; and (3) CPU scheduling mechanisms that propagate these capabilities up to the application level. Two main contributions of this research are the following: We have shown how the commercially successful wormhole routers can be extended with minimal hardware modifications to support QoS in clusters. The proposed router, called MediaWorm, includes two modifications to provide predictable performance. First, the virtual channels (VCs), which were originally proposed for improving performance by time-multiplexing different packets/flits on the same physical channel, were statically allocated to different traffic classes. Second, the traditional FCFC or round robin (RR) scheduling was replaced by the VirtualClock scheduling to provide rate proportional bandwidth to different traffic classes. It was shown that a cluster designed with the MediaWorm routers can  provide soft guarantees to MPEG II media streams in the presence of both best-effort and media traffic. Next, the design was extended for allocating the VCs dynamically to different classes of traffic. Second, for end-to-end QoS assurance, we have designed a QoS-capable NIC based on the virtual interface architecture (VIA) design paradigm. The design involves three modifications to the original VIA: (i) Inclusion of a prioritized doorbell scheme for informing the NIC the arrival of different traffic classes; (ii) Partitioning of the NIC buffer to a number of VCs compatible with the router design; and (iii) Providing a rate proportional scheduling of the VCs to inject flits into the network. Co-evaluation of the QoS-capable routers and QoS-capable NICs revealed that QoS provisioning in the NIC is more critical than that in the router/network. We believe that our NIC study is the first effort in highlighting the importance of network interface design for QoS support.

    This project was described byAdmin Istrator (18. May 2011 - 10:56)
    This project was last edited by Sanja Tumbas (24. June 2012 - 20:41)

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