Allied Telesis x908 - Manual (Page 21)

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C613-16119-00 REV A
Some protocols also use filters, so use some of the length
The following protocols use filters, and therefore use up some of the available profile length
and filter entries:
CPU
protection
CPU protection is enabled by default. It controls the rate at which packets reach the CPU,
and uses filters to ensure that ARP and unregistered multicast packets get prioritised
appropriately.
It matches on:
Ethertype—2 bytes to check for ARP, and
VLAN tagging—2 bytes to check for tagged ARPs, and
destination MAC address—6 bytes to check for unregistered multicasts (01-00-5E-00-00-xx),
or
destination IP address—4 bytes to check for unregistered multicasts (224.0.0.x).
CPU protection automatically changes from using the destination MAC address to the
destination IP address if you configure a filter that uses destination IP address (as long as no
other filter already uses destination MAC address). This minimises the impact CPU
protection has on the number of filters available. However, it still uses 8-10 bytes of width.
If you are sure your network will not have an excessive rate of broadcast and multicast traffic,
you can turn off CPU protection by using the command no platform cpuprotection.
EPSR EPSR matches on VLAN ID, which uses 2 bytes. EPSR is disabled by default.