On Sat, 24 May 2003, jfcm wrote:
Thinking of your last response I come back on a few point. I will
try to make the selling - target could be septembre thought.
Relation between A and D and D and B would be http. As thay are
toway. EVERY relation betweeen D and C should be OCP. Several
reasons:
- homogenity
- security (one single port) and
- money (this is where I could get the money for the development) :-)
My main interest is to see up to where OCP may be used.
OK. OPES covers a part of D-C relationship that deals with pA to pB
adaptation facilitated by OCP use. C and D can also agree to use OCP
for other purposes such as facilitating queries from C to A (via D).
Such OCP use is possible but is beyond OPES scope.
OCP is designed to facilitate message exchange and, hence, can be used
to exchange virtually any messages. After all, one can view response
generation as request adaptation!
The interest is that the dispatcher (D) would serve as a kind of
signaling. It caould be called by applications to know if the OPES
service par C is closed. In case of a reboot, that would be of use
to know what is underprocess.
Problem is that this keeping of state (see above) should be
maintained on D, C, B to reinitiate the situation in the case one or
two reboot.
OK. I guess there are several degrees of robustness here and several
ways to support them. One degree is being able to recover agent's last
state after a reboot without contacting other agents. There are known
techniques to do that, but they cannot handle a total agent
loss/replacement. If you make the state distributed/mirrored across
several agents, then you may be able to survive a total loss
(replacement) of one or more agents. Etc.,etc. It all depends on how
important it is to be robust in your particular environment.
Note, however, that OPES and OCP Core have nothing to do with all that
state recovery, even if they are actively used before, during, and
after recovery! OCP is nothing more than a communication protocol.
B querries A.
D comes in the between. So speks http bothe ways.
C speeks OCP with D.
No other relation. When C calls A itis through D (they are not in the same
domain! D is its gateway).
I think I understand that. You want to use OCP for several purposes.
That's fine. Some of those purposes may be out of OPES scope, but it
is great if OCP can be reused outside of OPES scope!
Alex.