> If objects that are always intended to be ephemeral are never going to
> conflict (but may lie on top of) local config, there is never a conflict.
> There is simply referential integrity issues if the underlying local
config is
> deleted and ephemeral config remains.
> 
> If the objects are always disjoint, there is never a conflict.
> 
> But if you permit an ephemeral object to override a local config one
within
> the schema, we have this issue.  Our options would appear to be:

A lot of this discussion centers around the concept of a "configuration
change" and, more specifically, "static routes." This is actually what I was
trying to avoid early on by separating the concept of configuration state
from the concept of forwarding state... But, since we are here, one possible
point -- If I2RS is treated as, essentially, an alternate "protocol process"
running off box, rather than "yet another configuration mechanism," then
this problem falls out. There would be no such thing as a "static route
installed by I2RS," there would only be routes installed in the local
routing table that would be persistent only if the I2RS agent makes certain
to reinstall it after any "system event" that causes the route to fall out
of the table. 

Policy within a protocol (though I generally don't like the idea of
modifying individual routes at the protocol level) would be treated the same
way -- not as a route map or RPL statement "configured" on the device, but
as an individual change to an individual route. If an update is received for
this route, the local agent must remodify the route, rather than assuming
any modifications made would be persistent across updates to that specific
reachability information.

If this is all true, then there _should be_ no problems with something being
configured in two places -- if a single piece of reachability information is
installed into the local routing table twice, normal processing rules apply,
regardless of the source (generally speaking, the route with the lower admin
distance wins, no matter the source). I2RS would never "configure" a "static
route," but rather attempt to install a piece of reachability information
into the routing table, which then either succeeds or fails, depending on
the processing rules involved. The static route configuration isn't touched
by I2RS, so there's no issue of "which configuration wins."

I hope all that made sense.

:-)

Russ



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