We’ve had networks on our IXes that have had a gigabit/s or more of traffic going to our cache boxes when they had their own on-net cache boxes that were working as designed.
Many Content Delivery Networks (CDNs) have programs where you can get a node of theirs in your network to maximize performance, minimize costs, etc.. Google has their Google Global Cache nodes. Akamai has their Akamai Accelerated Network Partner program. Cloudflare, Facebook and others have programs as well, but I can’t readily find links to them.
If you have one of those nodes, why do you need to connect to them over an Internet exchange? Simply put, not all content a given CDN has is stored on every node. They all have algorithms they use to determine what content users of that box are likely to access. Those boxes are then loaded with that content. If something your customers want to watch isn’t on your local box, the CDN must direct you somewhere else to get it. It could be a different show, it could be a show you have, but at a different bit rate. Either way, it doesn’t exist on your cache box. If you aren’t peered with other boxes on an IX, guess where that goes. Yup, it goes out your transit. You’re now paying more for your customer to have a worse experience.
Maybe you’re concerned about traffic preferring the boxes you’re peered with over your own. While they all have a secret sauce that they won’t reveal to the public, they have documentation available on how to influence your use of them. Netflix explains here about half-way down the page how they do it. Google has a page that is all about how to configure your BGP environment. They all support some methods such as BGP communities, Local Pref, MED, AS-Path, etc. to influence how that traffic gets to you. Needing some help on how to set those and what they mean? We did a post last month that should provide some assistance on that.
Most important of all, don’t let misconceptions, misunderstandings, doubt, etc. get in the way of maximizing your use of what’s available to you. Reach out to support and we can have a conversation with whatever CDNs you like to make sure you’re comfortable with how everything is being used.