The maximum bandwidth of a QSFP+ (Quad Small Form-factor Pluggable) transceiver is determined by the number of channels and the data rate per channel supported by the module. QSFP+ is a high-speed, hot-pluggable transceiver module commonly used in data center and networking applications.

Each channel in a QSFP+ module supports a specific data rate, and the total bandwidth is the product of the number of channels and the data rate per channel. The most common data rates for QSFP+ modules include:

• 10 Gbps per channel: QSFP+ modules supporting 10 Gbps on each of the four channels, resulting in a total bandwidth of 40 Gbps.

• 25 Gbps per channel: QSFP+ modules supporting 25 Gbps on each of the four channels, resulting in a total bandwidth of 100 Gbps.

• 40 Gbps per channel: QSFP+ modules supporting 40 Gbps on each of the four channels, resulting in a total bandwidth of 160 Gbps.

• 100 Gbps per channel: QSFP+ modules supporting 100 Gbps on each of the four channels, resulting in a total bandwidth of 400 Gbps.

The specific data rate and total bandwidth depend on the design and standard compliance of the QSFP+ module. When selecting QSFP+ modules for your networking equipment, it's important to consider the required bandwidth for your application and ensure compatibility with the devices and infrastructure in your network. Additionally, newer transceiver standards, such as QSFP28, have been developed to support even higher data rates, surpassing the capabilities of QSFP+.