Application Troubleshooting

Network Visibility makes it easy to answer the question: Is the network impacting my application's performance? This page describes the high-level troubleshooting workflows and includes several examples of how to use these workflows to solve real-world network problems.

Application Dashboard: Are network conditions to blame for the issue?

From the Application Dashboard I see slow, very slow, error, or stalled transactions. Are network conditions to blame?

Network Agents collect network-performance metrics for each application tier. If you notice performance issues in the Application Flow Map, open a popup and click Network tab. Do you see correlations between the Response Time and the other charts? If so, it indicates that the Response Time is affected by:

  • TCP effects between the two tiers (Latency)
  • Performance Impacting Events at the client tier, server tier, or the network path between the tiers (PIE)
  • Errors setting up or tearing down TCP connections (Errors)

Application Dashboard

Go to the Network Dashboard, which shows the TCP and network context for the application. Each tier and link has a View Metrics right-click option that opens a context-sensitive dashboard. The dashboard charts make it easy to determine network root causes. Start from the top-left chart in each dashboard, then search for metric correlations in the other charts.

TCP and network context for the application

TCP and network context for the application

Tier Dashboard: Which network metrics on this tier correlate with my outlier transactions?

The link and tier dashboards both have a Network Pie - Contributors chart, which answers the question:Where are these network conditions occurring – on the client tier, server tier, or the network link?

In this example, the top chart shows that a spike in Stalled transactions is correlated with a spike in PIE (Performance Impacting Events); the bottom chart shows that these events occurred on the client tier. With this information, you can then locate other correlated metrics and identify the issues on the client tier.

Chart comparison

Basic Diagnosis:

You now have a set of correlated network metrics and associated tiers/links. In many cases, this information is enough to identify and resolve the issue. You can contact your network team and say: "I see the following network issues on tier X, link Y, and so on, and these issues correlate with performance issues in my application." You can send them a URL to the Network Dashboard and say: "Click on link Y and look at the connections. The issues are happening on one or more of these connections." This often provides enough information for the networking team to identify and resolve the issue.

Basic diagnosis

Network Dashboard (Advanced Diagnosis): On which TCP connections are these network issues occurring?

If you need to collect more information, you can drill down to the TCP connection(s) where the network conditions are occurring. Click the relevant network link and select Connections in the popup. Sort the table based on the KPI metrics for the monitored connections (Throughput, TCP Loss, PIE, Errors). You can then right-click a connection and view metrics in the Metric Browser, or in a context-sensitive dashboard.

Note: By default, Network Agents do not monitor individual connections. The recommended workflow is to enable connection monitoring only after you narrow an issue down to a specific set of links. See Dynamic Monitoring Mode and Network Visibility.