NeTS: Small: Collaborative Research: Configuration Management for Mobility Support in Cellular Networks

移动支持被认为是下一代互联网的一项基本服务。目前的蜂窝网络是唯一能够在现实中成功提供广域、无所不在的移动支持的大型基础设施。随着智能手机设备的爆炸性增长和移动数据流量的激增，蜂窝网络已经演变为一个日益异构化的网络系统。因此，管理移动性变得既有挑战性，又有回报。本项目旨在研究2G/3G/4G网络移动性管理的配置问题，以确保理想的移动性支持。这项研究侧重于评估两个结构属性：稳定性和可达性。稳定性意味着在恒定的网络条件下没有持续的振荡环路，而可达性意味着没有接入黑洞(例如，设备无法到达某些小区或甚至给定的移动技术(例如，4G))。该项目的成功不仅将识别和描述当今蜂窝网络中的错误配置，还将保护对快速扩张的移动信息基础设施的数万亿美元投资。所获得的结果可能会影响即将到来的5G无线网络的设计。拟议的研究有三个关键领域的技术贡献。首先，它采用了一种新的构型研究方法。它对有问题的情况进行建模和分析，针对移动性配置问题提出了不稳定和不可达的分类，并推导出每个有问题的实例的触发条件。根本问题在于其分布式但不协调的配置决策。第二，该项目涵盖了从理论到实践的活动。考虑到理论上发现的错误配置实例，它进一步在运行中的移动网络中对它们进行经验评估。它试图衡量它们在现实中的可能性，并量化它们对用户设备和网络基础设施的负面影响。需要分析不同的根本原因，包括单个参数内的策略冲突、不同类型参数之间的不一致以及设备和网络之间的不协调决策。最后，对移动网络中的配置管理提出了新的解决方案。这项研究简化了当前的方法，同时保留了其对参数的完全可配置性。为此，探索了最小复制决策规则和无多跳移动决策两种设计准则，以确保移动支持的稳定性和可达性。

Mobility support is deemed a fundamental service for the next-generation Internet. The current cellular network is the only large-scale infrastructure that successfully provides wide-area, ubiquitous mobility support in reality. With the explosive growth of smartphone devices and the surge of mobile data traffic, cellular networks have been evolving into an increasingly heterogeneous networked system. As a result, managing mobility becomes challenging yet rewarding. This project seeks to study the configuration issues on mobility management of 2G/3G/4G networks, in order to ensure desirable mobility support. The research focuses on assessing two structural properties: stability and reachability. Stability implies no persistent oscillation loops during constant network conditions, while reachability denotes no access black hole (e.g., certain cells or even a given mobile technology (e.g., 4G) cannot be reached by the device). The success of the project will not only identify and characterize misconfigurations in today's cellular networks, but also protect multi-trillion dollar investment in the fast expanding mobile information infrastructure. The obtained results may influence the design of upcoming 5G wireless networks. The proposed research has three key areas of technical contributions. First, it takes a novel approach to configuration study. It models and analyzes problematic cases and comes up with a taxonomy of instability and unreachability for the mobility configuration problems, and derives triggering conditions for each problematic instance. The fundamental problem lies in its distributed, yet not well-coordinated configuration decision-making. Second, the project covers activities from theory to practice. Given the misconfiguration instances discovered in theory, it further empirically assesses them in operational mobile networks. It seeks to measure their likelihood in reality and quantify their negative impacts on both the user device and the network infrastructure. The diversified root causes are to be analyzed, spanning policy conflicts within a single parameter, inconsistency between different types of parameters, and uncoordinated decisions between the device and the network. Last, the research proposes new solutions to configuration management in mobile networks. This research simplifies the current approach, while retaining its full configurability for parameters. To this end, two design guidelines of minimal replication of decision rules and no multi-hop mobility decision are explored in order to ensure both stability and reachability of mobility support.