13.3 DANE discovery

26.2473GPPProgressive Download and Dynamic Adaptive Streaming over HTTP (3GP-DASH)Release 17Transparent end-to-end Packet-switched Streaming Service (PSS)TS

The SAND specification [54] provides the sand:Channel element in the MPD to inform the client about the location and method to communicate with the DANE. That method of DANE discovery may be used for DANEs that are in-band with respect to the media delivery path, i.e. when the MPD server may be aware of SAND functionality in the network.

An inband DANE may also be discovered by a SAND header field in the HTTP header of an HTTP response to a request for DASH resources as defined in ISO/IEC 23009-5 [54]. In this case, no session is created between the DANE and the DASH client.

When the DANE is out-of-band with respect to the media delivery path, as is the case with the Network Assistance DANE and the Consistent QoE/QoS DANE, a more generic method for DANE discovery may be used, namely using the DNS protocol as described in TS 23.003 [57]. Toward this purpose, the UE needs a DANE Fully Qualified Domain Name (FQDN) for the DANE. The procedures for addressing and identification for Bootstrapping MBMS Service Announcement as described in clause 15.5 of TS 23.003 [57] shall be used for DANE discovery. Accordingly, the Fully Qualified Domain Name (FQDN) for the DANE shall be "dane.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org". The URL to establish the out-of-band connection with the DANE shall be:

http://dane.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org/

The DANE FQDN is composed of six labels. The last three labels shall be "pub.3gppnetwork.org". The second and third labels together shall uniquely identify the PLMN, as described in clause 15.5 of TS 23.003 [57]. The first label shall be "dane".

When receiving a DNS query on the DANE FQDN, the DNS server shall respond with the information, including IP address, of the DANE or DANEs that are available to the UE for SAND functionality, according to any of the defined SAND modes.

Specific modes of DANE may be identified with targeted DANE FQDNs, as follows:

– A Proxy-Caching DANE, if provided, shall be located at the FQDN "pcdane.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org" (first label is "pcdane").

– A Network Assistance DANE, if provided, shall be located at the FQDN "nadane.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org" (first label is "nadane");

– A Consistent QoE/QoS DANE, if provided, shall be located at the FQDN "qoedane.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org" (first label is "qoedane");

If a specific mode of DANE is queried, using the specific DANE FQDN, then the response informs of the IP address of that mode of DANE only.