Load balancing both the SP and IdP

[Brian Reindel]

We run an enterprise SSO solution where the SPs are load balanced and
the IdP is also load balanced in production. I've been reading up on
the stateful aspects of the Shibboleth IdP, and we're trying to figure
out the required configuration details. We often refer to the
stickiness as it pertains to the user's browser session. However,
isn't there communication that happens in the SP client (SOAP
requests) that require stickiness as well? So all around, if an SP and
an IdP begin negotiating then all future communication must happen
between that SP and IdP, no matter the channel. Is that correct? If
not, then at what point can the "break" happen?

Thanks,