Re: [CDNi] Ben Campbell's Discuss on draft-ietf-cdni-logging-25: (with DISCUSS and COMMENT)

[Stephen Farrell <[e-mail]>]

Cutting to (I think) the substantive bit...

On 19/05/16 02:11, Ben Niven-Jenkins wrote:
> My intention was to express my opinion that because the uCDN could
> have chosen to perform the content delivery itself the dCDN is not
> exposing any more information to the uCDN than the uCDN could have
> chosen to gather itself if it so desired and therefore IMO there is
> no need to provide different guidance for DNS redirection than for
> HTTP redirection.

Yes, I've seen arguments of that form offered a number of times.
I don't find it convincing myself, but recognise that other folks
do. And in every case so far, neither side has convinced the other,
and sometimes not even understood one another. But let's see if
we (me really:-) get better with practice...

In this case I'd argue that the "could have chosen" isn't really
true - presumably the uCDN deals with the dCDN because it's hard(er)
for the uCDN to do the work directly, so it's not really true that
the uCDN could have chosen to access the information, at least not
at the same cost.

And there may be aspects of meta-data that are just different because
the access was via the dCDN, e.g. perhaps some other client IP address
gets used if somethings multihomed, or some ISP infrastructure differs,
e.g. HTTP Forwarded might be present and visible to the dCDN but with
no similar thing for DNS (or vice versa). I'd not be surprised if even
more subtle differences existed over populations of transactions and
users and CDNs.

S.