I have a captured LLDP packet.
LLDP has a list of enabled capabilities (Router, Bridge etc.) but none of the capabilities in the list is Switch. The question is how can I know if the source which the packet arrived from is a Switch Device?
If there is no a concrete answer, proximate assumption will do.
Disclaimer: I cannot actively address the switch, I'm sniffing packets...
LLDP has a list of enabled capabilities (Router, Bridge etc.) but none of the capabilities in the list is Switch.
A switch is a bridge. The original bridges only had a few interfaces (usually two), and bridging was done with software. When technology advanced to bridging in hardware, and the electronics became cheap enough to increase the interface density on a bridge, a vendor coined the marketing term, "switch."
Modern switches are transparent (all interfaces use the same protocol) bridges. There are also translating bridges, e.g. a WAP (Wireless Access Point), which translates between ethernet and Wi-Fi.