[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["很难理解","hardToUnderstand","thumb-down"],["信息或示例代码不正确","incorrectInformationOrSampleCode","thumb-down"],["没有我需要的信息/示例","missingTheInformationSamplesINeed","thumb-down"],["翻译问题","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["最后更新时间 (UTC)：2025-08-29。"],[],[],null,["# Use case: Troubleshoot network connectivity\n===========================================\n\nIn this use case, you're a network administrator supporting a network that\nincludes several load-balanced applications. You've been alerted of a latency\nproblem and have been told that your organization's mobile application is\nintermittently slow and timing out. You know that a number of different users\nare affected, and that there have been no recent application deployments. The\nissue is likely related to a change in the environment and not the application.\n\nThe following use case demonstrates how Network Topology can help you\nquickly troubleshoot and investigate issues in your deployment.\n\nTopology details\n----------------\n\nThe deployment spans three Google Cloud regions (`us-central1`,\n`europe-west1`, and `asia-east1`). All external client requests are served by a\nsingle external Application Load Balancer that has multiple backends in each of the three\nregions. Client requests that come from one of three business regions (Americas,\nEMEA, and APAC) are served by application instances in the closest\nGoogle Cloud region.\n\nThe following topology shows the top-level hierarchy for the deployment:\n[](/static/network-intelligence-center/docs/network-topology/images/use-cases/auditing-topology.png) Network Topology example topology (click to enlarge)\n\nNetwork latency\n---------------\n\nIn this scenario, assume that you have a load balancer named `shopping-site-lb`.\nYou check the latency between external clients and the load balancer to see if\nthe latency between them has changed. You discover that it has and decide to\nfurther investigate the load balancer's backends.\n\n1. You filter the topology to show only the traffic for your external load balancer\n `shopping-site-lb`.\n\n After you apply the filter, Network Topology shows only the\n connections related to the load balancer, as shown in the following example.\n [](/static/network-intelligence-center/docs/network-topology/images/use-cases/auditing-filter.png) Filter for a load balancer (click to enlarge)\n2. Starting with the external clients in Americas, you click the traffic metrics\n between the Americas business region and the load balancer.\n\n Network Topology shows charts in the details pane. The\n information includes ingress and egress traffic between your selected\n entity and the connected entity. For example, Network Topology\n provides the latest values for queries per second (QPS) and the HTTP request\n latency.\n\n In the request latency chart, you see values for the 50th, 95th, and 99th\n percentiles. In this example, assume that all of the latency values are\n higher than you expected.\n3. To expand the time series charts to 6 weeks, at the top of the details pane, you select\n **6 weeks**.\n\n [](/static/network-intelligence-center/docs/network-topology/images/use-cases/troubleshooting-zoom.png) Expanding the chart^1^ (click to enlarge) \n\n ^1^The figure is for reference. Its data doesn't reflect the use\n case.\n\n You see a significant jump that happened about two hours ago, roughly when\n the first issues were reported. You're confident that the issue is related\n to increased latency with the load balancer.\n4. Having a high-level view of the issue, you investigate the load balancer\n further by going to the **Load balancing** page in the Google Cloud console. You\n eventually find that an instance in the load balancer's backend service was\n taking longer than normal to respond. You take that instance out of service,\n which resolves the issue.\n\nWhat's next\n-----------\n\n- [Monitor your networking configuration with Network Topology](/network-intelligence-center/docs/network-topology/how-to/audit-troubleshoot-networking-issues)\n- [Use case: Audit network performance](/network-intelligence-center/docs/network-topology/concepts/auditing-network-performance)\n- [Troubleshoot Network Topology](/network-intelligence-center/docs/network-topology/support/troubleshooting)"]]
