The MAC table on the switch can indicate which direction a device is located. However, not every record refers to a single device plugged directly into that port.

Basic approach

Forwarding Database establishes a relationship between the MAC addresses and ports learned by the bridge. There can be many devices behind an uplink. The physical map drawn without considering the aging of learned records, VLAN context, and port mappings can be misleading.

Application steps

  1. Store MAC record along with port and VLAN information.
  2. If multiple MACs are seen on the same port, consider that there may be another switch or virtualization layer in between.
  3. Support direct connection claim with neighborhood data or site verification.

Practical example

Just because 30 different MACs appear on port 24 does not mean that 30 cables are connected to that port. The port may be an uplink to another switch. It would be more accurate to show this finding on the map as evidence of orientation.

Interpret the result correctly

FDB records are not instantaneous complete inventories; silent devices or old recordings may affect the result. Using a dashed link, source tag, and unknown status is more useful than a visually beautiful but technically incorrect map.

Source and follow-up reading

Protocol or command details: RFC 4188. The steps and example scenario are IPScans editorial narrative.