Routing and Scheduling Issues in Support of Advance Reservations

该提案的总主题是综合分组网络中的高级预留。预先保护分布式应用程序所需资源的能力正变得越来越重要。这不仅适用于需要同时访问多个设施和多台复杂设备的高端科学或医疗应用，而且适用于视频会议等更普通的应用，其合理的资源要求使得需要确保必要的网络资源与会议参与者同时可用是可取的。对提前预留的支持涉及多个方面，例如对协议的扩展，特别是对预留(信令)协议的扩展，以及增强的资源管理过程，例如，通话准入。虽然已经有许多以前的工作解决了这两个方面，但相应的两组问题通常是分开考虑的。此外，已使用的提前预订模式基本上侧重于单一的服务模式，即从给定的开始时间和给定的持续时间(在开始时间和持续时间中可能都有随机成分)提供一定数量的资源。因此，这项提议的目标是联合调查对资源管理的协议扩展和改进，并考虑为提前预订提供更一般的服务模式。具体地说，研究人员将在OSPF协议扩展的情况下考虑提前预订请求的路由问题，其中链路状态更新已被扩展以在不同的时间间隔上携带资源可用性信息。这允许分布式实现，其通过避免将所有提前预订请求转发到中央服务器来提高可伸缩性。然而，它引入了新的问题，以便在确保足够的性能的同时遏制协议流量的相应增加。在这种情况下，研究人员将研究与信息准确性和路由性能之间的权衡相关的问题，并调查使用抢占优先级等机制来为应用提供一系列服务选项，例如，在低优先级请求大量带宽，而在高优先级请求少量带宽。此外，研究人员还将再次与相关的路由问题一起考虑高级预留模型的各种扩展，例如最小化完成时间、最大化可用带宽等，这些扩展对于可以根据可用服务修改其行为的自适应应用是潜在感兴趣的。研究人员认为，联合开发必要的基础设施，例如对OSPF协议的扩展，以及对传统提前预订模式的可取扩展的调查，将使他们能够在我们对支持提前预订的内在复杂性的基本理解以及我们部署这种能力的能力方面取得重大进展。

The general topic of the proposal is advanced reservations in itegrated packet networks. The ability to secure in advance the resources needed by a distributed application is becoming increasingly important. This is true, not only for high-end scientific or medical applications which require simultaneous access to several facilities and pieces of sophisticated equipment, but also for more mundane applications such as video-conferencing, whose reasonably high resources requirements make it desirable to ensure that the necessary network resources are available at the same time as the conference participants are. Support for advance reservations involves multiple aspects such as extensions to protocols, and in particular reservation (signalling) protocols, and enhanced resource management procedures, e.g., call admission. While there has been a number of previous works addressing both of these aspects, the corresponding two sets of issues have typically been considered separately. In addition, the advance reservation models that have been used, have essentially focused on asingle service model, i.e., the availability of a given amount of resources, from a given starting time, and for a given duration (with possibly a random component in both the starting time and the duration). The goals of this proposal are, therefore , to investigate jointly protocol extensions and enhancements to resource management, as well as consider more general service models for advance reservations. In particular, the researchers will consider the problem of routing of advance reservation requests in the context of an extension to the OSPF protocol, where link state updates have been extended to carry resource availability infromation over different time intervals. This allows for a distributed implementation which improves scalability by avoiding that all advance reservation requests be forwarded to a central server. However, it introduces new problems in order to contain the corresponding increase in protocol traffic while ensuring adequate performance. In that context, the researchers will study issues related to the trade-off between information accuracy and routing performance, and also investigate the use of mechanisms such as preemption priorities to offer applications a range of service options, e.g., request large amount of bandwidth at a low priority together with a small amount at a high priority. In addition, the researchers will also consider, again jointly with the associated routing problem, various extensions to the advanced reservation model, such as mininmizing completion time, maximizing available bandwidth, etc., that are of potential interest to adaptive applications that can modify their behavior according to the available service. The researchers believe that the joint development of the necessary infrastructure, e.g., extensions to the OSPF protocol, and the investigation of desirable extensions to the traditional advance reservation model, will allow them to make significant progress in both our basic understanding of the inherent complexity in supporting advance reservation, and our ability to deploy such capabilities.