Technical Summary
This document is a standards track submission that defines a
protocol by which an upstream CDN (uCDN) may query a downstream CDN
(dCDN), in a CDN Interconnection (CDNI), as to whether the dCDN
will accept a client redirected from the uCDN, and if so, to where in the
dCDN the client should be redirected. It is necessary for the recursive
redirection mode of CDNI. The WG believes that a standardized
method/protocol for determining if a dCDN is able and willing to
serve content for the uCDN is needed and will be useful.
Review and Consensus
Because iterative redirection is simpler and more widely used today,
the WG's focus was primarily on iterative redirection; consequently,
there was less discussion on recursive redirection. There was
significant review within the working group, with no notable
technical disagreement. An early AppsDir review was done, which
specifically looked at the JSON encoding, and all comments from
that review were addressed.
A security concern was raised and discussed by the WG. The
protocol supports DNS redirection because CDNs use DNS redirection
today. Without DNSSEC, however, a client may not be able to
distinguish legitimate DNS redirection from a DNS-based attack.
The WG agreed that the concern should be documented (which it has
been), but that the existing functionality should move forward with
the understanding that DNSSEC is not a reasonable requirement for
all DNS redirection. The security aspects are being pursued in a
separate draft.
Personnel
The document shepherd is Kevin J. Ma. The responsible AD is Alexey Melnikov.