Fragmented packets sent directly to a JUNOS device will not efficiently clear from route engine's packet memory (mbuf). This exposes the router to additional risk, where mbuf can fill to where no other packets can be accepted. The creates a denial of service against the router's control and management plane traffic. In most cases the fragmented packets will time out and get cleared from mbuf, restoring service. In rare cases, the fragmented packets will not be cleared.