Using Wireshark for troubleshooting unknown protocol drops on a router interface

Hello,

Is there a way within Wireshark to capture traffic between a router and a switch between two interfaces without being physically connected to any of these devices? I would like to find out what protocols the router keeps dropping (please see below).

 50486066 packets input, 11916465873 bytes, 0 no buffer
     Received 1030652 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 252636 multicast, 0 pause input
     58872028 packets output, 36007876614 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     **247772 unknown protocol drops**
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out

Thanks for the help.