This is not actually (as in yes it does matter) the case, if a file comes from a CDN it is often a close and low latency source that will run up to very high speeds. For example in our case we connect to local peering exchanges (or PNI’s/local caches) at 100G or Nx10G with latency to the end user in the 1-30ms range resulting in very large peaks of local backhaul traffic. If a file is delivers from source or from remote CDN’s/exchanges these are located in other countries with between 25ms (New Zealand to Australia) and 130-200ms (New Zealand to LA/SJC or Singapore) latency, this results in a much slower and normally barely noticeable traffic blip. Yes as an ISP we need to carry the traffic in both cases but the first case can result in a 20-30% local backhaul increase for a couple of hours and in the second case its just BAU traffic for a day or two. Local CDN is obviously the better option for cost and the consumer, but you certainly do notice the traffic in local backhaul.
From: NANOG <[email protected]> On Behalf Of Tom Beecher Sent: Friday, 2 April 2021 10:05 am To: Matt Erculiani <[email protected]> Cc: North American Operators' Group <[email protected]> Subject: Re: wow, lots of akamai If thousands of users are downloading 50G files at the same time, it really doesn't matter if they are pulling from a CDN or the origin directly. The volume of traffic still has to be handled. Yes, it's a burden on the ISP, but it's a burden created by the usage created by their subscribers.
