Allied Telesis AT-S63 - Manual (Page 84)

Chapter 6: Port Parameters
84 Section I: Basic Features
Rate Limiting
The limit on the number of ingress packets of a particular type that
the port accepts per second. The possible settings are:
B-Broadcast - Status of broadcast packet rate limit (enabled or
disabled) and number of packets per second.
UM-Unknown Multicast - Status of unknown multicast packet
filtering (enabled or disabled) and number of packets per second.
UU-Unknown Unicast - Status of unknown unicast packet filtering
(enabled or disabled) and number of packets per second.