Something we learned about the old CCS 330 (the original Combat System, not the current CMS330 suite) was that the 4x Data Bus lines were run on separate decks, on opposite sides of the ship.
That way if there was a hit on the port side, and you lost both channels, you might still have both the channels on the Stbd side online.
Then, as you did your trouble-shooting, you could re-terminate the BAS (Bus Access Set) to shorten the data bus and get some additional redundancy back online.
It was a very well shielded Tri-Axial cable that was used.
It was something that we figured out relatively late in the life of CCS.
That sort of planned redundancy was built into the Halifax Class.
With systems that have been retrofitted, or modified, or added, there may not have been that same level of engineering acumen applied. The original CIWS was definitely configured differently from the version on the ship which had a big fire that may be the one I'm thinking of impacted in this discussion.
I think back in the 70's and 80's when the CPFs were designed, the RCN had a much better depth of field in terms of naval architects than we do now, and perhaps some of the things we've rushed into operations that have become 'standard' should have had more engineering applied.
I ponder the 'engineering' that we applied as we sat on the Bridge-top of HMCS Montreal in 2005 in a foreign port in the Med trying to figure out how to install an AIS receiver. We may have been hungover. We definitely didn't have a useful instruction manual, but between 2 Comm Techs and me the Sonar Tech, we got it installed, we connected it to a GPS signal, we tied it into the Kelvin Hughes for an AIS Overlay, and we managed to get good ranges by not putting it too close to any of the emitters on the bridge-top. A few ports later, I happened to bump into an OSL guy at an airport, and he told me how to tie the AIS into SHINNADS as well - so we became the first ship in the fleet to have AIS info showing up on our SDM.
There was no redundancy....but we got it working anyhow.
(There may also have been no formal approval from anyone by the CO to the CSEO....but....)