Business Case: An interaction the user has with the web-based application or website that has meaning in a business context. It could be as simple as viewing a single page, or as complicated as performing an entire transaction. In web performance trainer, this represents a series of HTTP Transactions that should be repeated by virtual users during a test.
Cache: The web browser maintains a copy of recently requested resources (pages, images etc.) so that when the resource is needed again, it does not have to ask the server for another copy. This greatly improves the performance of the browser-especially on a graphics-laden website where images (menu bars, for instance) are reused on multiple pages.
Controller: Web performance trainer can be run in two modes-as the controller or as an engine. In controller mode, web performance trainer presents a GUI that allows the recording, editing and execution of load tests. Only one controller may be run on a network with the same license key.
Cookie: A small amount (less than 1k usually) of text that a web server asks the web browser to store on the browser computer. This information is sent back to the server each time the browser makes a request for a URL on that server. This is the most common (and most preferred) method of session tracking. Country to popular opinion, cookies cannot be used by hackers to run harmful programs on your computer or steal account numbers from your Quicken files (except for Microsoft Internet Explorer-which requires a security patch to prevent such abuse).
Delay time: The amount of time between receipt of one URL and the request of the next URL. Web performance trainer records this duration while recording a business case and uses it to accurately simulate a user behavior when performing a test. When a delay time occurs between a web page, the delay time is usually due to the processing time required by the browser to parse the page and render it (and the images) on the screen. When the delay time occurs after the final image in a web page and the next web page, the delay time represents the time spent buy the user reading the page and deciding what to do next. In this case, the delay time is referred to as Think Time.
Engine: Web performance trainer can be run in two modes-as the controller of as an engine. In engine mode, web performance trainer presents a console interface and listens for commands from a controller. The controller for generating virtual users uses it. Lmany engines can by used by a controller to generate massive network loads.
FTP (File Transfer Protocol): A network protocol for sending and receiving files. FTP is built on top of TCP/IP
HTTP (Hypertext Transfer Protocol): The protocol used between web browsers and web servers to transfer web pages and associated files (images, etc). It is the language of the World Wide Web. HTTP is built on top of TCP/IP.
HTTP Transaction: A request sent from the browser to the server and the corresponding response from the server to the browser, both sent using HTTP. This round-trip communication path allows the browser to request a resource (URL) and receive a response from the server. It may include content sent by the browser (data entered in from fields, uploaded files) and content returned from the server (web page, image, etc).
Host: A computer that is connected to a TCP/IP network, include the Internet. Each host has a unique IP address.
IP (Internet Protocol): A Network protocol that specifies the format of data transferred between two hosts (called packets or data grams) and the addressing scheme. IP by itself is something like the postal system. It allows you to address a package and droop it in the system, but there is no direct link between you and the recipient. ILP is generally used in conjunction with TCP.
IP address: An identifier used by the IP protocol to identify an individual host. The current version of IP, Ipv4 uses 4 numbers to identify each network address. Each number can be in Inc. web server. Note that certain IP addresses have special meanings. 127.0.0.1 is the ‘loop back’ address that a host uses to redirect traffic to it self (usually for diagnostic proposes). The address ranges 10. *. *. *And 192.168. *. * Are always reserved for internal networks. 127. *. *. *, 0. *. *. * and 255.255.255 are also reserved for special uses.
License key: An encrypted file that contains the critical license information for your installation of web performance Trainer.
Multihome: An adjective used to describe a host that is connected to two or more networks or has two or more network addresses. For example network server have multiple network interfaces to increase maximum throughput.
Proxy server: A server, typically on a private network, that allows access to external network resources. In a common network configuration, the computers on a company network are separated from the Internet by a firewall (for security reasons). Since these computers cannot access the Internet directly to browse web pages, the browser must be configured to use a proxy server (which is allowed to access the internet) to service requests for web pages from the Internet. All common browsers support this configuration, usually in a configuration section titled “Use a proxy server”.
Sample period- A time period during a load test during which data is aggregated. The statistics calculated by web performance Trainer are calculated for each sample period during the test.
Session Tracking: HTTP is ‘stateless’. This means that between the time your browser receives a web page and asks for the next page, the server has forgotten who you are-in other words, when your browser asks for the second page, it has no way to know that it was the same browser that asked for the first page. This is obviously a problem for any application that needs to remember who you are-such as an application that requires a login. The notion of a singles, unique user browsing from one page to another is referred to as a ‘session’. As the web has evolved, several techniques for session tracking have evolved. The most common are cookies and URL-rewriting.
SMPT (simple Mail Transfer Protocol): A network protocol for transferring e-mail messages between servers. Most e-mail systems that send mail over the Internet use SMPT. SMPT is built on top of TCP/IP.
TCP (Transmission control Protocol): A network protocol that enables two hosts to establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which they were sent. TCP is a little like a phone call-there is an extended connection between two hosts during which either host can send data to the other.
TCP/IP: The suite of communications protocols used to connect host on the Internet. TCP/IP uses combines the TCP and IP protocols to provide addressing and reliable data transfer for a variety of other Internet protocols, including HTTP, FTP and SMTP.
Think Time: The time between the browser displaying a page to the user and the user clicking a link to browse to the next page. This time could be the time it takes the user to read the content of the page or decide what to do next. Web performance trainer records this time when recording a Business Case and uses it to accurately simulate the uses when performing a test. See also Delay Time.
TTFB-TTFB: Stands for “Time to First Byte” and is the duration between the times the virtual user made an HTTP request, and the time the first byte of the response from the web server arrived. This value gives an idea of the responsiveness of the network and web server, and consists of the socket connection time, the time to send the HTTP request, and the time to receive the first byte of the HTTP response.
URL (Uniform Resource Locator): A specially formatted string that describes a resource on the Internet. The browser to determine uses this where on the network the resource is located. A typical URL looks like this:
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