The expectation is that you will be able to use a load-balancer as you
describe. There shouldn't be any particular OPES protocol
configuration issues involved in the setup. If you find some, let us
know.
The tracing and billing informatio is slightly different. You say
that it might go back to the OPES processor(?) (through the
load-balancer?) or to some other location. This non-specifity of
destination is outside the OPES protocol, and you'd probably do best
to just have the callout servers open a direct connection to the
billing server. However, you'll need to think about whether or not
the OCP message headers give you enough information to correlate the
billing with the connection that triggered the callout server.
If you simply attach the billing data to the adapted stream and let it
flow back to the OPES processor, you'll need to write code that
recognizes and detaches that data and sends it to your billing server.
You could use OCP to communicate with the billing server, I suppose,
but there are probably any number of other protocols that would be
just as good.
Hilarie