In mixed-vendor network environments, such as deployments that include bothFortiSwitchandCiscodevices, properLayer 2 discovery protocolsmust be enabled to allow devices to automatically discover neighbors and exchange essential device and interface information. FortiSwitchOS 7.6 supports bothCisco Discovery Protocol (CDP)andLink Layer Discovery Protocol (LLDP)to ensure interoperability.
Cisco Discovery Protocol (CDP)is a Cisco-proprietary Layer 2 discovery protocol widely used by Cisco switches, routers, and IP phones. When CDP is enabled on FortiSwitch interfaces, Cisco devices can discover FortiSwitch neighbors and receive information such as device ID, port ID, platform, and capabilities. This is particularly important in Cisco-centric networks where CDP is the primary discovery mechanism.
Link Layer Discovery Protocol (LLDP), defined by IEEE 802.1AB, is a vendor-neutral discovery protocol supported by both Fortinet and Cisco devices. Enabling LLDP allows FortiSwitch and Cisco devices to exchange standardized information including system name, port description, VLAN information, and management address. LLDP is essential for cross-vendor compatibility and is commonly enabled by default in modern enterprise networks.
The remaining options are incorrect.Unidirectional Link Detection (UDLD)is used to detect unidirectional fiber or copper link failures and does not provide device discovery or information exchange.LLDP-MEDis an extension of LLDP specifically designed for media endpoints such as IP phones and is not required for general switch-to-switch discovery.
Therefore, to ensure automatic discovery and information exchange between FortiSwitch and Cisco devices,both CDP and LLDP must be enabled, makingOptions B and Cthe correct and fully verified answers based on FortiSwitchOS 7.6 documentation.
