Troubleshooting › General Troubleshooting › Increase in Network Round Trip Time (NRTT) › Determine the Cause of a Degradation in Performance

Determine the Cause of a Degradation in Performance

Determine if another application is active on the network:

1. Click the Engineering page.
2. Select the following Settings from any Response Time view:
   • Application -- All
   • Server -- All
   • Network Set - the relevant aggregation, such as the remote site aggregation as shown below
3. On the Response Time Composition view, click the blue hypertext Application link to see all applications that are being monitored by the management console on this server.

   If another application appears in the resulting Performance Map, complete these steps again for this application to determine if it is the problem source of the performance issue.

   The key is an increase in the number of observations at the same time a performance issue was reported.

4. If no other application appears in the resulting Performance Map, use the back arrow to go back to the main Engineering page. Select Trends from the horizontal menu and check whether this performance event demonstrates a pattern over the past weeks and month. If a pattern appears you need to use historic NetFlow data, IP accounting, or protocol analyzer data to determine if an application was saturating the network at the times in question. If no historical data is available, you can manually review the time in question on a projected recurring time and date to identify the problem source application.

   Examples of applications that create issues for the primary application on a network are:

   • Replication or backup data between remote sites
   • Large file transfers between servers
   • Users streaming large amounts of data on subrate WAN links (< T1)
   • Anti-virus upgrades across subrate WAN links

Determine if network has become unreliable:

1. Check the switch port facing the server and the server NIC to ensure that it is set for the correct duplex and speed settings (see the following table) and is free from errors.

1. Determine if the network has become unreliable because of configuration issues or network errors by setting up thresholds in the management console to launch an investigation when NRTT exceeds accepted values. The management console automatically gathers relevant information from routers and switches.
2. Review router and switch logs, interface errors, and change records to discover any events that might be affecting the stability of the network, such as routing divergence and circuit errors.