I'll take a stab at this, based on the assumption that all we
need is one new header ...
Question to the group: What's the consensus - should we explicitly
allow/support callout server chaining?
It's impossible to prevent it, it would be good to support it. I don't
think there's any impact on the protocol beyond adding a "This is part
of a callout chain" header.
If yes, what are the impacts
with respect to complexity,
local configuration must show which servers are available for OPES
processing, but that's not part of the protocol we are developing
reliability,
might have more delays, more opportunity for broken connections
fault-tolerance,
slight increase in most cases, due to more machines being available
for processing
data integrity,
no change
privacy, security,
if machines are in the same admin domain, no change; would recommend
strongly that machines be restricted from communicating outside the
admin domain, but there's no way to enforce this
etc?
Don't know of any.
What are the specific scenarios in
which such a mechanism would be beneficial?
Anytime the communication overhead is much less than the processing time
one will find that pipelining is a good idea. This also relieves the
OPES data processor from having to maintain a map of the services points
within the local infrastructure - the first service processor can plan
the processing pathway, handle failure detection and failover, etc.
And would the expected
benefits outweigh the additional complexity?
There's little complexity added to the protocol.
Hilarie