Hi,
MSMs in a BD8800 have 2 different roles:
- Management (1 is Master, 1 is Backup)
- Fabric (Forwarding of packets between modules)
So for Management, 1 is enough. For forwarding, you need both for full forwarding rate. With 1 MSM, you have half capacity. Please note that it's only for traffic ggoing from a Packet Processor to another (slot to slot or between ports on IO with multiple PP).