If your redundant Supervisor engines are running software version 4.1, the uplink ports on the standby engine are disabled until it becomes the active supervisor. What strategies might you need to employ to ensure that failover works for the uplinks?
Referring to Figure A-1, if you connect the uplink ports from the active supervisor module on Cat-A to the active supervisor on Cat-B, everything works well until one of the supervisors fail. The now active uplinks on the standby module of Cat-A are connected to the inactive uplinks on the standby module of Cat-B. Connectivity might be lost, Spanning Tree reconverges. Therefore, you might want to cross connect modules as in Figure A-2 or Figure A-3. The strategy of Figure A-2 enables only one link to be active at a time, whereas the strategy of Figure A-3 allows two links to be active at a time. Another alternative is to not use the Supervisor ports for uplinks, but use them for host connections instead.