Civil Engineering Reference
In-Depth Information
Fig. 4.32
Structure of CanKingdom
ments. The Document is the key for the Cities to encode or decode the Pages. A
Document can contain one un-enumerated Page or more enumerated Pages. Cities
have matching Documents for coordinated tasks; one is set up for transmission and
the other ones for reception. The King uses a King's Document to configure each
City. In this process, he assigns Envelopes to matching Documents. Then no CAN
ID (except the one for the King's Document) is predefined and a system designer is
free to give any message its proper priority. A Document can contain not only data
but also tasks, e.g. a Letter with a blank Page or even a Letter for another City can
be used for triggering the execution of tasks in one or more Cities. A programmer
may see the transmission entities as threads (Fig.
4.33
):
4.5.5
King's Document
The King's Document contains many Pages, one for each rule. The Kingdom
Founder has to implement all King's Pages supported by any City he/she will use
in his Kingdom in order to set up each City in a proper way. The King's Document
contains then at least three Pages (the mandatory rules) but also any Pages corre-
sponding to additional rules implemented by selected Cities. All King's Pages use
the Envelope 0 (CAN ID 0 Std) as default. (This number can be changed if neces-
