CDN

As returning readers of this blog would be aware - I found a trick to find Facebook caching servers around the world during the APRICOT 2018 hackathon. Since then I am running my code again every year to see the changes and publish this report.

Previous reports

1. March 2018 here
2. Nov 2019 here
3. April 2021 here

Facebook knows!

Back in 2019, I was in San Francisco, California for NANOG 75. While roaming around in the lobby, someone read the NANOG card hanging around my neck and greeted me. His 2nd line after greeting was “Oh I know that name, you are the guy who mapped our caching nodes” and we both laughed. I must say this specific category of the post has brought some attention around.

Over last couple of years I posted updates on Facebook caching nodes (FNA) deployment across the world. If you would like to read the logic I am using to pull the data, you can check the original post here. While the data is about Facebook FNA, it’s highly likely that networks would have Google GGC nodes alongside (a bit less) Akamai caches.

My last post about it was back in Nov 2019 and it seems just about the time to do a fresh check. So here we go…

In March 2018 I mapped nodes of Facebook globally using the airport string they use in the CDN URLs (detailed post here). Since then I posted a couple of times updates on as they are adding more nodes. There also have been questions via emails and comments on the blog in recent times about updated data.

Here goes latest data as on 22 Nov 2019. It’s published here.

 

Global stats

• Total nodes increased from 2204 as from Aug 2018 to 3184 now in Nov 2019.

Earlier this year after APRICOT 2018, I posted a list of visible Facebook FNA (CDN caching) nodes across the world with IPv4, IPv6 and the AS name. I got quite a few mails in following months about people mentioning that they installed nodes but do not see their names in the list (and that was normal since list was static). 

I re-ran my script to see emailslatest status of nodes. During last check I saw 1689  nodes (3rd March). Now on 26th Aug i.e after close to 6 months, the total number of nodes has increased to 2204.

Just back from APRICOT 2018. As I mentioned in my previous blog post, APNIC had its first Hackathon and it was fun (blog post of APNIC here). There was one project on the ranking of CDNs using RIPE Atlas data. To achieve this team was trying to find strings/hostnames which they can trace to and figure out nearby CDN. As part of that, I suggested them to look into www.facebook.com and carefully noting the sources from where elements get loaded. It’s quite common that Facebook.com (or Google.com for the logic) would be hosted on some server at a large PoP while FNA (or GGC) would serve only specific static content out of it. FNA, of course, sits on the IPs of the ISP hosting it. So in the source list, we found scontent.fktm1-1.fna.fbcdn.net and that gives an idea that FNA strings are around logic: scontent.fxxx1-1.fna.fbcdn.net where xxx is the airport code. 1-1 means 1st PoP in 1st ISP over there probably (strong guess!). If there are more FNA nodes in a given area, the number goes further up. The team used it and for now, the project is over. But while I was on the way back to India, I thought that this is very interesting data if we pull the full picture by querying all possible IATA airport codes with a logic. This logic can be used for two things: