Internet visibility
Internet visibility provides you with insights into the customer data centers or delivery platforms and applications. You can get information such as availability, response time, and throughput measurements from every network across the globe and application specific metrics such as page load time, page render time. Radar forms the backbone of the data collection methodology.
Radar uses a JavaScript script embedded within a content page or application provider’s pages to collect information about the performance and availability of a data center or delivery platform.
The Radar client is a JavaScript application that runs on customer webpages and inside mobile applications. Its core purpose is to gather network performance data used to drive intelligent routing decisions via Openmix, and provide optional plug-ins to enable other NetScaler Intelligent Traffic Management services, such as Page Load Time, Page Resource Timing, and Video Playback Metrics.
The Radar client is full-featured, yet lightweight, and unobtrusive. The client waits until after most of the page resources have downloaded before performing the bulk of its work, and all network communication is performed in an asynchronous manner wherever possible. These instructions specify which platform to measure next during the session, picked from among the community platforms and any private platforms specific to that community member. They also indicate the types of measurements to be performed, which includes availability, round trip time, throughput, or other metric collection. For more information, see Radar.
To make it as small as possible, the JavaScript is compiled with advanced optimizations using the Google Closure Compiler. Advanced optional features are delivered as plug-ins for customers opting to use them. For more information, see Visualizer.
Impact offers a powerful view into the performance and business KPI data collected while visitors are on your site. The application data collection is radar-based and apart from integrating the Javascript tag, no extra configuration is required. For more information, see Impact.
Navigate to Intelligent Traffic Management > Internet Visibility. Click Internet Visibility to log in to the internet traffic management portal and view the radar reports, performance, and business KPI data.
For more information, see NetScaler Intelligent Traffic Management documentation.
Activate radar for a private data center
Today’s business environment demands the ability to run an application that is both globally connected and consistently high performing. To achieve this, you need a tool that measures real-time internet performance across all major clouds and CDNs, and across a global network.
Radar uses a JavaScript script embedded within an application provider’s pages to collect information about the performance and availability of a multi-site application. Radar takes measurements from about 900 million users across 50,000 ISP networks, resulting in 10 billion data points every day, which enables you to ensure that the content and applications are always available, and the users receive the best experience.
Real user measurements (RUMs) on such a significant scale are achieved through Radar. RUMs can be achieved through radar tags and objects. A radar tag is a JavaScript tag integrated with the application provider’s pages you want to measure. The radar object can be deployed on the site using a responder policy and action. Responder action and policy serve a 43 bytes single pixel image whenever a URL with the extension r20.gif is requested by the user’s browser.
When users access an application provider’s page, the radar tag runs and instructs the browser to retrieve radar objects, collect the metrics and send the telemetry to Radar.
The public cloud site locations have radar configured by default. If you’re using a private data center, you must manually configure the radar. The NetScaler Console service provides its application providers the ability to deploy the radar objects and measure the performance of their private data centers. The radar collects the following metrics:
- Availability: Specifies whether the radar object loads or not.
- Response Time: Specifies how long it takes for the server to respond to a subsequent request, once all of the noise of establishing a connection is completed. This is a relatively close approximation of TCP round-trip time (RTT) from the browser to the provider.
- Throughput: Throughput is the data rate of the connection, in kilobits per second, as measured from the retrieval of a 100 KB object.
These metrics allow the customer to effectively evaluate an existing content delivery strategy and take advantage of the Optimal RTT GSLB algorithm for hybrid multi-cloud applications. The information collected remains available only to the application provider. After configuring radar, the application provider can choose to become a radar member. Radar members are the application providers who have radar configured on their sites and also share their metrics with the radar community. Contact NetScaler support to understand the benefits of collecting community measurements.
Note:
You can view metrics collected from radar configuration under Intelligent Traffic Management > Internet Visibility.
To summarize, the radar RTT measurement process follows these steps:
- Users visit the application (webpage) with a radar tag and when they download a webpage, they receive the radar tag.
- When the page has finished loading, the radar tag initiates a request to each site.
- The radar tag retrieves the small radar objects to determine the HTTP response time.
- The data is collated and sent to the radar community. Based on the data, perform an optimal RTT and route the traffic to the site with the lowest RTT.
Activating radar for a private data center is a two-step process:
- Integrate radar tag in application webpages.
- Deploy radar objects on a site in a private data center.
Integrate radar tag in customer webpages
Prerequisite: To integrate the radar tag, you must know your customer id. Contact NetScaler support to know your customer id. For more information on contacting NetScaler support, see https://support.citrix.com/article/CTX128597.
Based on your need, you can choose one of the following methods to integrate the radar tag:
Note:
Do not change the JavaScript snippet. The code includes important information which if changed can create unexpected or unreliable behavior.
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Default tag: The default tag is the recommended version of the radar tag. The default radar tag waits until the load event is complete before downloading and running the radar client, ensuring that the load event is uninterrupted.
<script> if (typeof window.addEventListener === "function") { window.addEventListener("load", function() { if (window.cedexis === undefined) { var radar = document.createElement("script"); radar.src = "//radar.cedexis.com/1/<cid>/radar.js"; // replace with user specific value document.body.appendChild(radar); } }); } </script> <!--NeedCopy-->Replace
<cid>with your customer id in the radar tag and place it in the HTML of the webpages just before the closing BODY tag. -
Pre-loading Radar Tag: If you’re using Content Security Policy settings, to prevent the use of inline JavaScript, use pre-loading radar tag. This radar tag keeps the download of the radar client from blocking further parsing of the page, but runs it before the load event has fired.
<script async src="//radar.cedexis.com/1/<cid>/radar.js"></script> <!--NeedCopy-->Replace
<cid>with your customer id in the radar tag and place it in the HTML of the webpages you want to measure. -
Radar Native SDKs: The Radar SDKs include client libraries that you can easily incorporate into any iOS or Android mobile app. The SDKs allow you to embed the Radar tag functionality, to take periodic measurements from the native application, without having to manually load and manage a web view.
- iOS: https://github.com/cedexis/RadarKit
- Android: https://github.com/cedexis/AndroidRadar
- Headless: https://github.com/cedexis/radar-runner
- Web Services: https://github.com/cedexis/webservices
Deploy radar objects
You can deploy radar objects in one of the following ways:
- Deploy radar objects on a host in a private DC.
- Integrate with NetScaler Console.
Deploy radar objects on a site in a private data center
Prerequisite: To serve the radar objects using TLS, ensure that the following certificates are available in the corresponding paths:
| Certificate | Path |
|---|---|
| Public TLS certificate | /etc/ssl/public.crt |
| Private TLS key | /etc/ssl/private.key |
| Certificate chain | /etc/ssl/ca-certs.pem |
Radar objects can be served by any modern operating system and webserver. The following instructions are tested against Ubuntu20 in Apache.
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Install Apache2 and git packages.
sudo apt-get install apache2 git <!--NeedCopy--> -
Create and populate the Apache2 directory.
sudo mkdir -p /var/www/radar-objects sudo git clone https://github.com/cedexis/testobjects /var/www/radar-objects/ <!--NeedCopy--> -
Disable the default Apache2 virtual host.
sudo rm /etc/apache2/sites-enabled/000-default.conf <!--NeedCopy--> -
Enable the Apache2 mods as follows:
sudo a2enmod headers sudo a2enmod rewrite sudo a2enmod ssl sudo systemctl restart apache2 <!--NeedCopy--> -
Add the Apache2 site configuration.
cat > /etc/apache2/sites-available/radar-objects.conf << 'EOF' ErrorLog ${APACHE_LOG_DIR}/error.log CustomLog ${APACHE_LOG_DIR}/access.log combined DocumentRoot /var/www/radar-objects Header add "Timing-Allow-Origin" "*" RewriteEngine on RedirectMatch 404 /\.git <VirtualHost *:80> RewriteRule ^/img/(.*)/(.*)$ /img/$2 [L] RewriteRule ^/sm/(.*)/(.*)$ /sm/$2 [L] </VirtualHost> SSLStaplingCache shmcb:${APACHE_RUN_DIR}/logs/stapling_cache(128000) SSLSessionCache shmcb:${APACHE_RUN_DIR}/logs/ssl_scache(512000) <VirtualHost *:443> SSLEngine On SSLCertificateFile /etc/ssl/public.crt SSLCertificateKeyFile /etc/ssl/private.key SSLCACertificateFile /etc/ssl/ca-certs.pem SSLProtocol -all +TLSv1.3 +TLSv1.2 SSLCipherSuite "EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384 EECDH+aRSA+SHA256 EECDH+aRSA+RC4 EECDH EDH+aRSA RC4 !aNULL !eNULL !LOW !3DES !MD5 !EXP !PSK !SRP !DSS" SSLUseStapling On SSLSessionCacheTimeout 300 RewriteRule ^/img/(.*)/(.*)$ /img/$2 [L] RewriteRule ^/sm/(.*)/(.*)$ /sm/$2 [L] </VirtualHost> EOF <!--NeedCopy--> -
Enable the new Apache site and restart Apache2.
sudo ln -s /etc/apache2/sites-available/radar-objects.conf /etc/apache2/sites-enabled/radar-objects.conf sudo systemctl restart apache2 <!--NeedCopy--> -
Verify if the radar objects are being served.
curl https://<FQDN>/img/r20.gif <!--NeedCopy-->
Integrate with NetScaler
You can deploy the radar object using NetScaler. You can either use the command line or the NetScaler Configuration Utility. For more information, see https://docs.citrix.com/en-us/citrix-intelligent-traffic-management/radar.html#integration-with-citrix-adc.