Browser/proxy server caching - Campaign Manager 360 Help (2024)

Browsers get site content and ad content from servers. Webpages have code that instructs browsers to "call" servers to request this content, including images and videos. When your browsers cache content, they store it on the user's computer (or a proxy server) for later use. Once content is cached, the browser no longer has to request it from servers. This speeds up load times.

The trouble is, Campaign Manager 360records impressions on your ads based on content requests. If a browser caches ad content for a particular ad, it will not need to request the ad content when your ad tag fires. Without a request, Campaign Manager 360cannot log an impression.

Cache busting is a way to prevent browsers from caching your ad content. Cache busting adds a random string to your ad tag each time the tag fires — typically a random number. Because the tag has a different number each time, the browser sends a new request each time. The browser can't tell that it has already cached content associated with your tag because the tag has a different random number each time it fires.

Generally, tags use random number generation (RNG) to dynamically add a random number to your tag each time it fires. This number is a value for the ord= attribute.

If your publisher uses Ad Manager, insert the %n macro after ord= in your tags. E.g., ord=%n. If there is already an ord value, replace it with %n.

In order for the landing pageand the image to work correctly, you must place the variable as the value of the ord= key in both the <HREF>and the <IMG SRC> tags.

Only Ad Manager knows to expand %n into a random number, so do not use this RNG unless your publisher uses Ad Manager.

About RNGs

As discussed above, an RNG inserts a random number into your ad tag each time it fires. If the tag is different each time (because it has a different random number), the browser sends a new ad request each time the tag fires. This ensures that impressions are logged each time your ad appears, and that the browser does not use its caached content.

An RNG is best implemented with a macro that the publisher's system automatically expands into a random or different value each time the tag fires.

If your publisher doesn't use Ad Manageras its adserving solution, you should still add a cache buster, such as a timestamp variable or a random number generated by an RNG that the system recognizes.

Sample RNGs

For DART Enterprise, RealMedia, or Adforce, the publisher can replace the [timestamp] component of the tags with these variables:

These variables are guidelines only. Please verify the timestamp for your ad serving solution with your contact at the respective company, as these variables vary according to the third-party ad server version.