A comparison of hard-state and soft-state signaling protocols
A comparison of hard-state and soft-state signaling protocols
复制标题
硬状态和软状态信令协议的比较
DOI：
10.1145/863955.863984
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
D. Towsley
中科院分区：
文献类型：
--
作者：
P. Ji;Zihui Ge;J. Kurose;D. Towsley
从电话网到面向VC的数据网，再到因特网，所有电信网络中的关键基础设施组件之一是其信令系统。可以识别两种广泛的信令方法：所谓的硬状态和软状态方法。尽管发出信号具有根本的重要性，但我们对这些方法的理解--它们的利弊以及它们最好使用的环境--大多是轶事（偶尔也是宗教）。在本文中，我们比较和对比各种信令的方法，从一个“纯”的软状态，软状态的方法增加明确的状态删除和/或可靠的信号，一个“纯”的硬状态的方法。我们开发了一个分析模型，该模型允许我们量化单跳和多跳信令场景中的状态不一致性，以及与给定信令方法及其参数（例如，状态刷新和移除定时器）。在类的软状态的方法，我们发现，一个软状态的方法加上明确的删除大大提高了状态的一致性程度，同时引入了很少的额外的信令消息开销。添加可靠的显式设置/更新/删除允许软状态方法实现与硬状态方法相当（有时更好）的一致性。
One of the key infrastructure components in all telecommunication networks, ranging from the telephone network, to VC-oriented data networks, to the Internet, is its signaling system. Two broad approaches towards signaling can be identified: so-called hard-state and soft-state approaches. Despite the fundamental importance of signaling, our understanding of these approaches - their pros and cons and the circumstances in which they might best be employed - is mostly anecdotal (and occasionally religious). In this paper, we compare and contrast a variety of signaling approaches ranging from a "pure" soft state, to soft-state approaches augmented with explicit state removal and/or reliable signaling, to a "pure" hard state approach. We develop an analytic model that allows us to quantify state inconsistency in single- and multiple-hop signaling scenarios, and the "cost" (both in terms of signaling overhead, and application-specific costs resulting from state inconsistency) associated with a given signaling approach and its parameters (e.g., state refresh and removal timers). Among the class of soft-state approaches, we find that a soft-state approach coupled with explicit removal substantially improves the degree of state consistency while introducing little additional signaling message overhead. The addition of reliable explicit setup/update/removal allows the soft-state approach to achieve comparable (and sometimes better) consistency than that of the hard-state approach.