Interesting,
so it is an MTU problem after all, I take it there’s no way
to adjust the BPF (Berkeley Packet Filter) limit to let the
6020B sized PSNPs through?
Probably could - but I'd prefer solutions that don't mess with the
base system, which ensures long term usability of FRR across future
upgrades.
The BPF man page has an interesting bug note:
BUGS
The read buffer must be of a fixed size (returned by the
BIOCGBLEN
ioctl).
A file that does not request promiscuous mode may receive
promiscuously
received packets as a side effect of another file requesting
this mode on
the same hardware interface. This could be fixed in the kernel
with ad-
ditional processing overhead. However, we favor the model where
all
files must assume that the interface is promiscuous, and if so
desired,
must utilize a filter to reject foreign packets.
Data link protocols with variable length headers are not
currently sup-
ported.