Automatically Repairing Network Control Planes Using an Abstract Representation
Automatically Repairing Network Control Planes Using an Abstract Representation
复制标题
DOI：
10.1145/3132747.3132753
复制
发表时间：
2017-10
期刊：
影响因子：
--
通讯作者：
Aaron Gember;Aditya Akella;Ratul Mahajan;H. Liu
中科院分区：
文献类型：
--
作者：
Aaron Gember;Aditya Akella;Ratul Mahajan;H. Liu
计算机网络的转发行为由分布式路由协议和访问过滤器的配置（统称为网络控制平面）控制。不幸的是，控制平面配置通常是错误的，导致网络违反了重要的策略：例如，特定的流量类（按源和目标端点定义）应始终能够到达其目的地，或者始终跨越航路点。由于路由器，交通类别和策略之间的交流性质相互缠绕，手动修复这些配置令人生畏。受自动程序维修的最新工作的启发，我们介绍了CPR，该系统自动计算正确的，最小的网络控制平面维修。 CPR将配置修复作为MAXSMT问题，其约束基于基于Digraph的对照平面语义的表示。至关重要的是，该表示形式必须捕获由控制平面构建体的跨交通类别产生的流量类别之间的依赖性。 MAXSMT公式必须考虑这些依赖项，同时还要考虑所有策略，并且更喜欢将配置更改的大小（例如，行数）最小化。使用来自96个数据中心网络的配置，我们表明CPR在不到一分钟的时间内为98％的网络提供维修，并且这些维修需要更改相同或更少的配置行，而不是手写的维修。
The forwarding behavior of computer networks is governed by the configuration of distributed routing protocols and access filters---collectively known as the network control plane. Unfortunately, control plane configurations are often buggy, causing networks to violate important policies: e.g., specific traffic classes (defined in terms of source and destination endpoints) should always be able to reach their destination, or always traverse a waypoint. Manually repairing these configurations is daunting because of their inter-twined nature across routers, traffic classes, and policies. Inspired by recent work in automatic program repair, we introduce CPR, a system that automatically computes correct, minimal repairs for network control planes. CPR casts configuration repair as a MaxSMT problem whose constraints are based on a digraph-based representation of a control plane's semantics. Crucially, this representation must capture the dependencies between traffic classes arising from the cross-traffic-class nature of control plane constructs. The MaxSMT formulation must account for these dependencies whilst also accounting for all policies and preferring repairs that minimize the size (e.g., number of lines) of the configuration changes. Using configurations from 96 data center networks, we show that CPR produces repairs in less than a minute for 98% of the networks, and these repairs requiring changing the same or fewer lines of configuration than hand-written repairs in 79% of cases.