Re: IS-IS Error (FRR)

[Mark Tinka <mark.tinka () seacom mu>]

On 20/Apr/20 16:26, adamv0025 () netconsultings com wrote:
> 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.

Mark.