What does it mean when they say the switch is 100Mbps but it has higher or lower backplane. Or the switch is 1000Mbps but it has higher/lower backplane.
Mpps is how many packets the switch can forward per second. It's usually given for the minimum packet size of 64 bytes packets. For Ethernet, 100 Mbps requires 148,809 pps. Divide by 10 for 10 Mbps, multiply by 10 for gig.
The switch fabric capacity, is the internal bandwidth that connects all the ports.
An an example, a wire rate switch for eight 100 Mbps ports, should have 148,809 pps * 8 = 1,190,472 (or about 1.2 Mpps) and 8 * 100 Mbps * 2 (duplex) = 1.6 Gbps internal bandwidth.
You'll find many switches are unable to run all ports concurrently at full speed (they run short of pps and/or bandwidth), but again, seldom is this necessary.