Unaware of any one concise document but how it works is as follows:
The fabric/backframe/bus/"guts" of a network device might document its bandwidth capacity. For non-blocking, in the Cisco world, you need 2x all your duplex ports.
For example, for a device supporting 2 full duplex gig ports, the internal core would need a 4 gig capacity.
Forwarding bandwidth is calculated by a frame's/packet's size by how many can be forwarded per second. As frame's/packet's can vary forwarding requires more frames/packets per second to provide the same bandwidth usage.
Often device's bandwidth forwarding capacity "shrinks" as the frame's/packet's size shrinks.
Notice in what you posted, 118 Gbps for 1400 bytes. Ask, what Gbps for 64 bytes (or for "Imix")?
