The term "SFP port" refers to a port on networking equipment, such as switches, routers, or network interface cards, that is designed to accept a Small Form-factor Pluggable (SFP) transceiver module. The capacity of an SFP port itself is not fixed; instead, it depends on the type of SFP transceiver being used and the specifications of the networking equipment.

SFP transceivers come in various types, each designed for specific purposes and supporting different data rates and distances. Here are some common types of SFP transceivers and their respective capacities:

1. SFP (1 Gbps): The original SFP modules support data rates up to 1 Gbps (Gigabit per second). These are commonly used for Fast Ethernet and Gigabit Ethernet connections.

2. SFP+ (10 Gbps): The SFP+ modules support data rates up to 10 Gbps, making them suitable for 10 Gigabit Ethernet connections. SFP+ ports are often found in data center switches and high-performance networking equipment.

3. SFP28 (25 Gbps): SFP28 modules support data rates up to 25 Gbps, typically used in 25 Gigabit Ethernet connections.

4. SFP56 (50 Gbps): SFP56 modules support data rates up to 50 Gbps, commonly used in 50 Gigabit Ethernet connections.

5. QSFP (40 Gbps): While not technically an SFP module, the Quad Small Form-factor Pluggable (QSFP) is related. QSFP modules support data rates of 40 Gbps, and there are variations such as QSFP+ and QSFP28, each supporting different speeds.

6. QSFP56 (100 Gbps): QSFP56 modules support data rates up to 100 Gbps, making them suitable for 100 Gigabit Ethernet connections.

The capacity of the SFP port, therefore, depends on the specific SFP transceiver module installed in that port. When choosing an SFP module and considering the capacity of the port, it's essential to match the module's data rate and specifications with the requirements of the network and the equipment in use. Always refer to the manufacturer's documentation for accurate information about the supported capacities of SFP ports on specific networking devices.