[j-nsp] qfx-5200 bcm fragmentation oddity

[Franz Georg Köhler]

On Tue, Aug 29, 2017 at 01:35:49PM -0400, Jared Mauch <jared at puck.nether.net> wrote:
> has anyone seen where a qfx-5200 sends fragment needed when it’s not
> needed if the DF bit is set in the packet?

If packet is too large and DF bit is not set, the router will
fragment the packet if needed. If DF bit is set, the router must not
fragment and therefore will notify with ICMP fragmentation needed
because it cannot be forwarded without fragmentation or reducement in
size.