[c-nsp] SUP720 to RSP720 upgrade using SSO

[Brett Looney]

> Does anyone know if it's possible to upgrade two SUP720-3B modules to
> RSP720-3C (one at a time) using SSO on a 7600, thus minimizing downtime?

Supervisors must (physically) match exactly within a chassis. You'll find
that the primary will boot and then the secondary will not fully initialise
because the hardware doesn't match the primary. Therefore, SSO is not an
option.

B.