Can anyone explain what these IPs refer to? YouTube CDNs? Some commercial service?
$ whois 173.194.55.0
I won't include the whole output, but here is the link of the allocation: http://whois.arin.net/rest/net/NET-173-194-0-0-1
Basically, this listed IP block is part of a much larger allocation for Google. I don't know exactly what type of google service is hosted from it, but it isn't a commercial CDN.
> nslookup o-o---preferred---sn-mv-p5qe---v17---lscache1.c.youtube.com/
> Name: o-o.preferred.sn-mv-p5qe.v17.lscache1.c.youtube.com
> Address: 206.111.9.12