Lecture Notes in Computer Science 3472

490 George Din
A B
C D
MEM = 256 MB
CPU = 800 Mhz
MEM = 256 MB
CPU = 800 Mhz
X
X X Y
SUT
MEM = 128 MB
CPU = 800 Mhz
X Y
MEM = 256 MB
CPU = 800 Mhz
Fig. 16.7. Example of a heterogeneous distributed execution environment
during the execution and distribute them between B and C according to their
memory capabilities.
Distribution of components is a mathematical function of different parameters.
This function is applied either at deployment time for each component
(when its deployment is required) or for all components at once (if known)
In the following function definition, D is the distribution function, p1, p2, ...
pn are the parameters which influence the distribution and h1 is the home where
the test component should be distributed.
h1 = D(p1, p2, ..., pn)
Sometimes, it is also possible to compute the homes for all components (h1,
h2, ..., hm).
{h1, h2, ... hm} = D(p1, p2, ..., pn)
There are two types of parameters which are taken into consideration when
distributing test components:
• external parameters: bandwidth, CPU, memory
• internal parameters: the number of components, type of components, type
of behaviors, connections
The external parameters are application independent parameters whose values
depend on the execution environment and are constant for all applications
running on that environment. The internal parameters are related to the component
based application itself and are different for each application.
The TTCN-3 test components are distributed on different hosts. Unfortunately,
in TTCN-3 it is not possible to recognize a component by its id. This
problem appears when creating test components without names like in the following
example: