Connecting Devices to a Home Network/Device Discovery
The network layer consists of Ethernet, a LAN protocol widely used for home networking and Internet access, and an IP network based on wireless LAN technology. Devices on the home network are discovered using DHCP, which automatically assign IP addresses, and SSDP as defined in the UPnP Device Architecture. It is also possible to retrieve the names and functions of devices, and this information can then be used to select devices.
Server Content Discovery/Media Format Compatibility Checking
Using the structure defined in UPnP AV, it is possible to obtain a list of videos, music, photographs stored on a selected device, together with metadata related to this content. The guidelines also stipulate formats, including video formats, such as MPEG-2 and AVC/H.264 (the new MPEG-4 standard) and audio formats, such as linear PCM and MPEG-2 AAC, MP3 as well as media format profile IDs representing these formats.
At the content transfer stage, compatible content can be selected by using media format profile IDs to check compatibility between the server and the player. The selected content is transferred by HTTP. Link protection technology, such as DTCP-IP, is used when copyright-protected content is transferred.
Design guidelines formulated by DLNA cover the connection of devices to home networks, the discovery of other devices, the discovery of content on servers, media format compatibility checking and content transfers. Their purpose is to allow the seamless sharing of content within the home.
In September 2005, a home network transfer protocol for the ARIB standard for digital broadcasting in Japan was adopted. This protocol, which is based on the DLNA design guidelines and the DTCP-IP standard, will allow broadcast content and other information received through digital tuners to be transferred through a home network.