Diagnose network failures via data-plane analysis

Diagnosing problems in networks is a time-consuming and error-prone process. Previous tools to assist operators primarily focus on analyzing control plane configuration. Configuration analysis is limited in that it cannot find bugs in router software, and is harder to generalize across protocols since it must model complex configuration languages and dynamic protocol behavior. This paper studies an alternate approach: diagnosing problems through static analysis of the data plane. This approach can catch bugs that are invisible at the level of configuration files, and simplifies unified analysis of a network across many protocols and implementations. We present Anteater, a tool for checking invariants in the data plane. Anteater translates high-level network invariants into boolean satisfiability problems, checks them against network state using a SAT solver, and reports counterexamples if violations have been found. Applied to a large campus network, Anteater revealed 23 bugs, including forwarding loops and stale ACL rules, with only five false positives. Nine of these faults are being fixed by campus network operators

Applying Formal Methods to Networking: Theory, Techniques and Applications

Despite its great importance, modern network infrastructure is remarkable for the lack of rigor in its engineering. The Internet which began as a research experiment was never designed to handle the users and applications it hosts today. The lack of formalization of the Internet architecture meant limited abstractions and modularity, especially for the control and management planes, thus requiring for every new need a new protocol built from scratch. This led to an unwieldy ossified Internet architecture resistant to any attempts at formal verification, and an Internet culture where expediency and pragmatism are favored over formal correctness. Fortunately, recent work in the space of clean slate Internet design---especially, the software defined networking (SDN) paradigm---offers the Internet community another chance to develop the right kind of architecture and abstractions. This has also led to a great resurgence in interest of applying formal methods to specification, verification, and synthesis of networking protocols and applications. In this paper, we present a self-contained tutorial of the formidable amount of work that has been done in formal methods, and present a survey of its applications to networking.Comment: 30 pages, submitted to IEEE Communications Surveys and Tutorial

Past Before Future: A Comprehensive Review on Software Defined Networks Road Map

Software Defined Networking (SDN) is a paradigm that moves out the network switch2019;s control plane (routing protocols) from the switch and leaves only the data plane (user traffic) inside the switch. Since the control plane has been decoupled from hardware and given to a logically centralized software application called a controller; network devices become simple packet forwarding devices that can be programmed via open interfaces. The SDN2019;s concepts: decoupled control logic and programmable networks provide a range of benefits for management process and has gained significant attention from both academia and industry. Since the SDN field is growing very fast, it is an active research area. This review paper discusses the state of art in SDN, with a historic perspective of the field by describing the SDN paradigm, architecture and deployments in detail

Fault diagnosis using automatic test packet generation

Recently networks are growing wide and more complex. However administrators use tools like ping and trace route to debug problems. Hence we proposed an automatic and Methodical approach for testing and debugging networks called Automatic Test Packet Generation (ATPG). This approach gets router configurations and generates a device-independent model. ATPG generate a few set of test packets to find every link in the network. Test packets are forwarded frequently and it detect failures to localize the fault. ATPG can detect both functional and performance (throughput, latency) problems. We found, less number of test packets is enough to test all rules in networks. For example, 4000 packets can cover all rules in Stanford backbone network, while 53 are much enough to cover all links. DOI: 10.17762/ijritcc2321-8169.15030

Monitoring and verifying network behavior using data-plane state

Modern computer networks are complex, incorporating hundreds or thousands of network devices from multiple vendors performing diverse functions such as routing, switching, and access control across physical and virtual networks (VPNs and VLANs). As in any complex computer system, these networks are prone to a wide range of errors such as misconfigurations, software bugs, or unexpected interactions across protocols. Previous tools to assist operators in debugging network anomalies primarily focus on analyzing control plane configuration. Configuration analysis is limited in that it cannot find bugs in router software, and is harder to generalize across protocols since it must model complex configuration languages and dynamic protocol behavior. This thesis studies an alternate approach: diagnosing problems through static analysis of a network's data-plane state. We call it data-plane verification. This approach can catch bugs that are invisible at the level of configuration files, and simplifies unified analysis of a network across many protocols and implementations. To prove the applicability and usefulness of data-plane verification, we designed and implemented two tools to rigorously check important network invariants, such as absence of routing loops, routing consistency of replicated devices, and other reachability properties. Our first tool, called Anteater, translates a network's data-plane state and invariants into boolean satisfiability problems, and checks them using a SAT solver. Our second tool, called VeriFlow, creates a device independent graph model of the network state, and uses standard graph traversal algorithms to detect invariant violations. We tested our tools with real world network data-plane traces, and with large emulated networks. Both of our tools were able to detect real bugs that went unnoticed to network operators for more than a month. Our tools helped them to narrow down the faulty configurations, and resolve those quickly. Results from emulated larger networks showed that the running time performance of our tools, especially that of VeriFlow, is good enough to detect bugs quickly before they can be exploited by outside attackers. Due to the fast response time of VeriFlow, it can be used in the emerging Software-Defined Networking (SDN) setting as a proactive tool to detect and filter out faulty configurations before they reach network devices

VeriTable: Fast Equivalence Verification of Multiple Large Forwarding Tables

Due to network practices such as traffic engineering and multi-homing, the number of routes---also known as IP prefixes---in the global forwarding tables has been increasing significantly in the last decade and continues growing in a super linear trend. One of the most promising solutions is to use smart Forwarding Information Base (FIB) aggregation algorithms to aggregate the prefixes and convert a large table into a small one. Doing so poses a research question, however, i.e., how can we quickly verify that the original table yields the same forwarding behaviors as the aggregated one? We answer this question in this paper, including addressing the challenges caused by the longest prefix matching (LPM) lookups. In particular, we propose the VeriTable algorithm that can employ a single tree/trie traversal to quickly check if multiple forwarding tables are forwarding equivalent, as well as if they could result in routing loops or black holes. The VeriTable algorithm significantly outperforms the state-of-the-art work for both IPv4 and IPv6 tables in every aspect, including the total running time, memory access times and memory consumption.Comment: INFOCOM 201

Scenario based security evaluation: Generic OpenFlow network

Demand for network programmability was recognized when development of protocolsslowed down due to network inflexibilities in 1980s. Research speeded up andmany proposals were made to solve architectural issues during 2000s. Academicworld put up an initiative to build up new programmable network architecturelater 2000s. OpenFlow was born.In modern public network infrastructures the security of the network architectureis crucial to archive data confidentiality, integrity and authenticity, yet high availability.Many studies have shown that there are many security vulnerabilities andissues on current OpenFlow implementations and even in OpenFlow specificationitself. Many proposals have been made to enhance these known issues. In thisresearch, the scenario based security evaluation of the generic OpenFlow networkarchitecture was carried out using technology publications and literature. Thesecurity evaluation framework was used in security assessment.Proposed risk mitigation patterns were found to be effective on most of the casesfor all 13 identified and evaluated scenarios. Lack of mandatory encryption andauthentication in OpenFlow control channel were most critical risks on generallevel. OpenFlow specification should provide clear guidance how this should beimplemented to guarantee inter-operability between different vendors. Short termsolution is to use IPSec. Second critical issue was that bugs and vulnerabilitiesin OpenFlow controller and switch software are causing major risks for security.Proper quality assurance process, testing methods and evaluation are needed toenhance security on all phases of the software production.Current OpenFlow implementations are suffering poor security. Tolerable levelcan be reached by utilizing small enhancements. There are still many areas whichneed to be researched to archive solid foundation for software defined networks ofthe future