Multi-CDN for tag delivery

A CDN is a collection of servers spread across the globe designed to serve content from locations in close proximity to users. However, not all CDNs perform equally. Even within the same CDN, performance may vary between regions and the time of day. Tealium has optimized these variances by building a multi-CDN system that applies real-time monitoring to multiple CDNs to ensure that our files are served as fast as possible.

The Tealium Multi-CDN infrastructure (mCDN) is designed to deliver files to your website as quickly and reliably as possible. The mCDN leverages multiple content delivery networks (CDNs) in real-time to determine the fastest delivery node in the respective geographic region.

How it works

The mCDN is responsible for the delivery of all files from the domain. This includes the main iQ Tag Management loader file, utag.js, all tag loader files (utag.#.js), and hosted data layer files.

  1. A web page with the Universal Tag (utag.js) makes a request to
  2. The local DNS server instructs the browser to contact DynDNS to resolve the host.
  3. DynDNS uses Cedexis to select the best performing CDN.
  4. Cedexis uses last mile data coupled with the requesting browser’s geographic location to determine which CDN performs best and directs the browser to that CDN.
  5. The selected CDN responds with the requested file.

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This page was last updated: January 7, 2023