How does nCDN work?

Question from NKN Telegram group:

Crypto Stud, [Nov 21, 2019 at 1:05:39 PM]:

Hi, I have a question regarding NKN’s coordinator functionality for the CDN product. I cant find any info on it. For CDN, are all assets such as images, videos, etc., cached on all edge nodes or is it a subset of nodes based on proximity to consumer? Is this what the coordinator does? Where can I read more about it? Thanks!

As I dont think its feasible for all network nodes to have a copy of the cached data

On a very high level:

    1. Tom want to access to watch “new kind of moon” movie
    1. NKN’s geoDNS server will locate the nCDN edge server that is closest to Tom’s computer or phone.
  • 3A) If “new kind of moon” movie is already in the local cache of that server, then it serves straight away.

  • 3B) If “new kind of moon” movie is not available on local machine, then the nCDN edge server will fetch a copy from source server (where all movies reside), cache it locally, and then server Tom.

    1. Local edge servers thus cache different subset of all the content that nCDN serves. And due to cache aging, local demand and storage limit, the local cache will update and rotate this subset.