In the first layer architecture, each node (Node) has 8 interfaces (Port), each node is connected to 8 leaf switches (Leaf), and every 20 nodes form a unit (SU), so in the first layer a total of 8*SU leaf switches are needed, 8*SU*20 cables (Cable) are needed . In the first layer architecture, each node (Node) has 8 interfaces (Port), each node is connected to 8 leaf switches (Leaf), and every 20 nodes form a unit (SU), so in the first layer a total of 8*SU leaf switches are needed, 8*SU*20 cables (Cable) are needed . The actual number of optical modules used primarily depends on the following factors. Discrepancies in Calculating the Ratio of Optical Modules to GPU-The Varying Usage Quantity Due to Different Networking Architectures. Network Card Model It mainly includes two network cards, ConnectX-6. The actual number of optical modules used mainly depends on the following aspects. 1, Same wavelength In a fiber optic link, data is transmitted from. When it comes to the connection between two fiber optic transceivers, the following four factors should be taken into considerations: wavelength, speed, fiber type, and the connection to switches.