tshark -ta -ni eth0 -o bgp.asn_len:40<br>
 desegment:<br>
      Whether the BGP dissector should reassemble messages spanning multiple TCP segments.<br>
       To use this option, you must also enable "Allow subdissectors to reassemble TCP streams" in the TCP protocol settings.<br>
<br>
 asn_len:<br>
   BGP dissector detect the length of the AS number in AS_PATH attributes automatically or manually (NOTE: Automatic detection is not 100% accurate)