Filtered to Area D

The upgrade envelope MUST state, for each kind of media, what upgrading it costs in total, worked out by the stack from what the library holds, or MUST say that the cost could not be worked out; it MUST NOT leave a surface to derive a total from a rate per hour (D2-R7, N24-R4).

The core MUST answer a member's session with the member's display name as the media server holds it.

A member's paired client MUST be able to watch a live TV channel only through the core, which MUST open the channel's live stream on the member's behalf only where the media server answers the channel's live TV read with the member's own session and the programme on it is within the member's limits (D8-R9). The guard's item question MUST NOT stand in for either answer.

The core MUST answer the client the location of the live stream's bytes at the guarded front door with a pass the core issued for that live stream and that member alone, which lapses within a bounded time, and MUST close the live stream when its pass lapses or the member is removed (D6-R8).

The guard MUST serve a live stream's bytes, its playlists and segments included, only to a request whose pass the core confirms, asked of the core on every such request, for exactly the live stream the request names, and MUST refuse one whose pass is absent, lapsed or not confirmed, or where the core does not answer. A live stream's bytes MUST NOT be served on an item's byte route (D11-R2).