From the perspective of the Tier n client process what's important is the time taken from sending the first Request packet to receiving the last Response packet.ĪPDU Response Time measures first request to last response Service Time In the diagram above we see a Request APDU split across four packets and a Response APDU split across three packets. Don't be put off by the talk of reference models, it's a very simple concept. The following diagram is our reference model for response time analysis. In the diagram above we see a Request APDU split across two packets and a Response APDU split across three packets. Typically a segment can only carry 1,460 bytes of data, and so if the APDU is, say, 2,000 bytes it must be split into two segments and hence two packets. Many APDUs are transported from client to service using TCP, and TRANSUM can analyze these types of flow.Īn APDU may not fit into a single segment. Response APDU that flows from service to client an example would be an HTTP 200 OK response Request APDU that flows from client to service an example would be an HTTP POST message When the processes communicate with each other, in almost all cases one will take the role of client and the other will provide a service.įlowing between the client and service we have application messages, which we will call Application Protocol Data Units or APDUs. We start by understanding that every multi-tier system is made up of multiple processes running on infrastructure. It's a simple concept but you'll need to understand it to make any sense of the TRANSUM output. The concept of Response Time Elements is key to the design and use of TRANSUM. The principle objective of TRANSUM is to enable an application or network analyst to be able to quickly pinpoint the cause of slow response times. Identify slow response times from components such as web, application and database servicesīreakdown the slow response times into network and service elements

TRANSUM extends the capabilities of Wireshark by providing a breakdown of the overall response time from a service in a way that makes it simple to: We can use a tool like Wireshark to analyze the data flows between the components. Network analysis is a tremendously powerful way to analyze the performance of a computer system, and Wireshark is by far the most widely used tool for this purpose. In this manual we refer to these types of issues as gray problems. When a performance problem occurs it can be difficult to determine the causing component let alone the fix. Today's business applications are delivered by complex multi-tiered systems. A particular challenge for network and application support people is identifying the cause of a slow response time issue.

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