Yes, the main line of the optical fiber LAN is a direct switch, followed by a router. The switch connected to the switch is called cascade. Most modern fiber-enabled network switches require an SFP transceiver module. ExtremeSwitching switches provide 2, 4, or 12 uplink ports implemented as s that pair a copper port using RJ45 connectors with an optical port using LC connectors. The copper port operates as an autonegotiating 10/100/1000BASE-T port. The optical port allows Gigabit Ethernet uplink connections. A combo port, also known as an optoelectronic multiplexing interface, is a photoelectric composite port with two kinds of Ethernet interfaces (RJ45 port and SFP port) on an Ethernet switch. In other words, it is a compound port that can support two different physical layers and share the same. Thus, it is recommended to connect only Cisco-compatible transceivers to Cisco equipment. You can obtain the list of compatible transceivers by visiting the Cisco Optics-to-Device Compatibility Matrix or run the show interface show interface transceiver supported-list command.
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