Allied Telesis Rapier Switch - Manual (Page 35)

Layer 2 Switching 35
Software Release 2.5.1
C613-02025-00 REV B
block, and then applies to all three packet types. Thus each of the packet types
are either limited to this value, or unlimited (NONE).
For the Rapier G6 series switches, each port is a processing block, and therefore
packet storm protection limits can be set for each port individually.
The BCLIMIT parameter specifies a limit on the rate of reception of broadcast
packets for the port(s). The value of this parameter represents a per second rate
of packet reception above which packets will be discarded, for broadcast
packets. If the value NONE or 0 is specified, then packet rate limiting for
broadcast packets is turned off. If any other value is specified, the reception of
broadcast packets will be limited to that number of packets per second. See the
note below for important information about packet rate limiting. The default
value for this parameter is NONE.
The DLFLIMIT parameter specifies a limit on the rate of reception of
destination lookup failure packets for the port. The value of this parameter
represents a per second rate of packet reception above which packets will be
discarded, for destination lookup failure packets. If the value NONE or 0 is
specified, then packet rate limiting for destination lookup failure packets is
turned off. If any other value is specified, the reception of destination lookup
failure packets will be limited to that number of packets per second. See the
note after the BCLIMIT parameter description for important information about
packet rate limiting. The default value for this parameter is NONE. If packet
storm protection limits are set on the switch, the PORT parameter must specify
complete processing blocks.
A destination lookup failure packet is one for which the switch hardware does not have
a record of the destination address of the packet, either Layer 2 or Layer 3 address. These
packets are passed to the CPU for further processing, so limiting the rate of reception of
these packets may be a desirable feature to improve system performance.
The MCLIMIT parameter specifies a limit on the rate of reception of multicast
packets for the port. The value of this parameter represents a per second rate of
packet reception above which packets will be discarded, for multicast packets.
If the value NONE or 0 is specified, then packet rate limiting for multicast
packets is turned off. If any other value is specified, the reception of multicast
packets will be limited to that number of packets per second. See the note after
the BCLIMIT parameter description for important information about packet
rate limiting. The default value for this parameter is NONE. If packet storm
protection limits are set on the switch, the PORT parameter must specify
complete processing blocks.
The ability of the switch to limit packet reception rates for different classes of packets is
dependent on the particular switch hardware. In particular, groups of ports may have to
have the same limits set, and the same limit may be set for the different types of packets,
depending on the hardware. Whenever packet rate limits are set on switches which have
this type of constraint, the latest parameter values entered will supersede earlier values.
When a command entered for specified ports changes the parameters for other ports, a
message will indicate these changes.
The SHOW SWITCH PORT command displays the packet storm protection
settings (Figure 3 on page 30).
SHOW SWITCH PORT=port-list