The selection of a downstream CDN by an upstream CDN is based on
multi-dimensional criteria. Various protocols, such as BGP or ALTO,
may be used by a downstream CDN to expose content routing information
and interconnection preferences to an upstream CDN. The selection of
such a protocol is premature as the WG, and especially the Footprint/
Capabilities Design Team, is currently working on this topic. So
this draft does not promote the usage of the ALTO protocol for CDN
interconnection. It presents the limitations of the current ALTO
protocol in the case it would be selected for CDN interconnection.
It specifies the mechanism for controlling the session initialization
and for limiting the information exchanged. Then it discusses the
need of incremental update and proposes to study the usage of Netconf
/Yang to provide ALTO server with notifications.