The HTTP feature is used to test or monitor HTTP servers.
Running an HTTP test gives you a good overview of the performance of a web site or web application, of the web server, and of the network between the web server and the Netrounds Test Agent. You can request web pages and verify response codes from distributed locations inside or outside of your network.
When you start an HTTP test, the Test Agents will make an HTTP Get request towards the specified URL and fetch the response. No rendering is done of HTML pages, so no additional requests are made for linked resources, (images, CSS files, and so forth). Measured parameters include TCP connect time, time until first byte received, time until last byte received, and download speed.
Traffic is initiated by the Test Agents, and the HTTP server reciprocates by sending traffic to the Test Agents using the same ports. This setup makes it possible to run tests also when the Test Agents are located behind a NAT.
HTTPS is supported, but no verification is done of the SSL certificate.
More information about HTTP in general is available in Wikipedia.
Setting up a test or monitoring
To run HTTP measurements you need to have at least one Netrounds Test Agent installed. If you haven't already done the installation, consult our quick start guides for various types of Test Agents in the section Netrounds Test Agents.
Create a new HTTP test or monitoring and fill in the mandatory parameters below:
- Duration (seconds): The duration of this test step in seconds. Min: 30 s. Max: 604800 s. Default: 60 s.
- Fail threshold (seconds): The maximum number of errored seconds (ES) that may occur without triggering a fail for this test step. Default: 0.
- Wait for ready: Time to wait before starting the test. The purpose of inserting a wait is to allow all Test Agents time to come online and acquire good time sync. Min: 1 min. Max: 10 hours. Default: "Don't wait", i.e. zero wait time.
- Clients: Specify the Test Agents you want to use in the test or monitoring.
- URL: The URL that the Test Agents will request.
- Time between requests (s): The time to wait between two consecutive requests. Min: 10 ms. Default: 10 s.
Thresholds for errored seconds (ES)
- HTTP response code: HTTP status code that must be matched in the HTTP response (e.g. "200 OK", which is the status code for a successful HTTP request). If the HTTP response code does not match this one, an errored second is triggered. Default: "200 OK".
- Timeout (ms): Maximum tolerated delay of HTTP response. If this value is exceeded, an errored second is triggered. Default: 3000 ms.
- Response content: Here you can enter a (case insensitive) regular expression against which the HTTP response content will be matched. If the response content is larger than 100 KB, only the first 100 KB will be used in the match. The response content is decoded using the character set specified in the Content-Type HTTP header, or ISO 8859-1 if no encoding is specified. The Content-Type MIME must be "text/*", otherwise the matching will fail.
- Request lifetime (ms): The maximum time Netrounds will wait for an HTTP response before the HTTP request is canceled. Default: 4000 ms.
- Proxy server: If set, the specified IP and port will be used as HTTP proxy.
- Proxy server port: Port to use as HTTP proxy port. Default: 8080.
- Proxy authentication: The authentication type used by the proxy server. If set, Proxy username and Proxy password should also be entered. Note: Currently there is an issue with NTLM authentication that causes Netrounds to measure too low connect time.
- Proxy username: User name used for HTTP proxy authentication.
- Proxy password: Password used for HTTP proxy authentication.
- Delayed start (s): (Tests only) Time by which to delay the start of the test within a test step. Default: 0 s.
SLA thresholds (monitorings only)
- SLA Good: Threshold for good fulfillment of service level agreement. Default: 99.95%.
- SLA Acceptable: Threshold for acceptable fulfillment of service level agreement. Default: 99.5%.
- Connect time (ms): Time taken to set up a TCP connection to the web server (time from sending TCP SYN until receiving TCP ACK).
- First byte received (ms): Time from sending the HTTP Get request until the first byte of the response is received. For a dynamic web site, the server side may take a while to generate the response.
- Response time average (ms): Average response time for the selected time period, that is, the average time taken to download the content from the URL.
- Response time min (ms): Minimum response time during the selected time period.
- Response time max (ms): Maximum response time during the selected time period.
- Size (KB): Length of the HTTP response, including HTTP headers.
- Rate (Mbit/s): Download rate of the response. Calculated as the size of the response divided by the total response time.
- ES timeout: Number of errored seconds triggered because no HTTP response was obtained before the Timeout period expired.
- ES response: Number of errored seconds triggered by an invalid HTTP response or by the HTTP response code or content not matching the specified ones.
- ES total: Aggregated errored seconds, taking into account all types of error.
- SLA: Service level agreement fulfillment for the test or monitoring: equal to (100 – ES total) %.