3Com SuperStack 3 3812 Implementation Manual page 58

58 C 6: U T M
HAPTER SING RAFFIC ANAGEMENT
Traffic prioritization and rate limiting are best used together if the egress
rate rather than the ingress rate is limited on a port; the traffic rate
leaving the Switch is limited rather than the traffic arriving at the Switch.
This ensures that the traffic is prioritized before rate limiting is applied
and the lowest priority packets are dropped first.
Rate limiting on ingress, as the packets arrive at the port, is not as
effective. The Switch cannot determine the order in which packets will
arrive and will not filter by priority.