Ports and (Internal) block diagrams

[Frederic]

Hello,
I am a little bit new on sysML, I hope you'll forgive me to query on a
basic question.

I try to modelize a system, allocated on several centres. Centre A and
centre B.
Centre A is divided into 2 parts : Part A1 and Part A2
Centre B is divided into 2 parts : Part B1 and Part B2

On a logical point of view, A1 communicates with B1 and A2
communicates with B2., so A1 has a standard port p_B1 and A2 has a
standard port p_B2

When I draw the internal block diagram of the system, I draw my system
with the two centres
centre A has a standard port for communication with centre B : p_B,
and B has a standard port for communication with centre A : p_A.

but, when I draw the internal block diagram of the centre A, should I
connect part A1 ports p_B1 and p_B2 to the port p_B ? If I do so, I
loose the information of the destination/provenance of the interfaces
exchanged with the parts. But if I create discriminated ports (one for
B1 and one for B2) It means that the centre ibd will contain more
ports, without signification at this level.

Could you help me, please ?

[Daniel Wadler]

i would use a single port on A and a single port on B.
However, for the provided and required interfaces i would use the interfaces of ports p_B1 and p_B2 as superclasses for the interface of p_B (iow i_B1 and i_B2 are superclasses of i_B). the same for ports p_A, p_A1, p_A2\i_A, i_A1 and i_A2.
see the attached example

this gets a bit more complicated when you start using required and provided interfaces, but has the advantage that you neither lose information, nor add superfluous ports which may inhibit alternate designs in the future (and generally add mess on the higher levels.)

- Daniel

> Date: Fri, 6 Nov 2009 05:09:51 -0800
> Subject: [SysML Forum] Ports and (Internal) block diagrams
> From: frederic....@gmail.com
> To: sysml...@googlegroups.com