In newer versions of Wireshark you can also just drag the field name from the Packet Details pane up to the Display Filter field and it'll create the filter for you, including the value of the field in that particular packet.In this second post I will look at Ethernet VPN (EVPN), what is it and how to configure a BGP EVPN session on Aruba devices. You can then edit the Display Filter that results to specify the value(s) you want to match. Since Wireshark is pretty good about showing the names of these values in the Packet Details view it's usually not even necessary to actually go to the associated RFC - just find the field in the Packet Details that seems to be what you're looking for, right click on it and select the option to create a filter with that field.

A quick Google search turns up RFC 4271, and Section 4.1 in that RFC shows that BGP OPEN messages have a Type of 1, so that'd be the Display Filter you'd use to show just those BGP messages. This often involves identifying a numeric value of the field that Wireshark is interpreting as the string displayed in the Info column, but that's not usually too hard since Wireshark usually bases those interpretations on the RFC if one exists, which is almost always the case for common protocols. However, if you can find a field in the actual packet that correlates with the value in the Info column you're interested in then you can build a Display Filter using that field. Wireshark can't filter the Info column with a Display Filter - the best you can do is search that column and go from one hit to the next.

Bgp wireshark packet capture