October 2006

Network Rules – Webinar and Seminar Series

VIAVI Solutions is hosting a series of seminars to help you manage a variety of network and technology challenges including:

  • Deploying and managing Voice over IP (VoIP)
  • Using network forensics and post-event analysis
  • Monitoring trends through effective reporting
  • Improving network visibility via NetFlow and sFlow®

The Network Rules Seminar Series will be presented in 8 cities throughout the United States. Registration is free and so is lunch. RSVP now and secure your spot.

In Practice: Application monitoring and long-term trending

Summary
Continuous monitoring and long-term trend analysis are critical for efficiently managing application service delivery. By understanding typical server and network behavior, you can establish benchmarks to define normal network performance and proactively handle issues before they impact your network.



In our example, an organization’s network administrator had been using Expert Observer’s Network Trending feature to track SQL application performance for a number of months. They knew from experience that average application response time for the SQL servers doesn’t often go above 60 milliseconds. Even though users hardly notice when response times exceed this level, it could mean trouble down the road. So in addition to running network trending, the administrator was in the habit of periodically glancing at Observer’s real-time application analysis response time chart.

 

One morning, the administrator started up Observer’s Application Analysis and saw the following response time analysis charts to the right.

In Practice
D1 Chart: Server performance degrading under steady load


The bottom chart (D2, the order processing database) shows a server in good shape. Transaction volume and response times are stable and within usual limits. The top chart, however (D1, the CRM database) shows trouble. Although transaction volume was flat, response times had been creeping up all morning. If the trend continued, the server could have come to a standstill.

 

 

In Practice
D2 Chart: Server performance acceptable


Because Observer® is a full-featured network analyzer, it was easy for the administrator to eliminate virus infection or hacker attack as possibilities by using Observer’s other diagnostic tools. Examining the server process table revealed a memory leak on the DB1 server. They restarted the system to solve the immediate problem, and later found a patch for the SQL server to fix the memory leak itself.

 



Tech Tip: Understanding Application Response Time: What does it measure?

Application response time answers the question: "How long did it take to fulfill the client's request?" Using SQL as an example, true application response time measures how long it took the server to deliver every last bit of data asked for by a client's SELECT request, down to the last data frame.

Some tools merely measure TCP handshake completion time or TCP ACK response time and call this "application response time." While these TCP metrics are useful in showing you TCP performance, they reveal nothing about problems your users could be having at the application level. If Layer 4 is all that is being analyzed, you won't be able to see any of the delay or failed transactions caused by server problems.

Calculating true application response time requires that the analysis tool have some hard-coded knowledge of the application being monitored and how its clients and servers communicate. For this reason, it is typically available for common applications, such as SQL, HTTP, FTP, etc. If an analysis tool claims to measure application response times for any and all custom applications, what it really shows is probably some form of TCP response time.

VIAVI Solutions’ Expert Observer, however, provides true application response time and analysis by having built-in intelligence to appropriately understand how specific applications, including SQL, Citrix, MS Exchange, HTTP, and FTP, interface with clients and servers.

   
 

 

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Coming to:
    • Boston
    • Chicago
    • Dallas
    • Philadelphia
    • Washington DC

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Washington, D.C. Oct. 16-17

Abingdon, Oxfordshire, UK Oct. 17-19

   
 

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