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Page 13 | AlliedWare™ OS How To Note: DHCP Snooping on Rapier-style switches
DHCP filtering
a maximum of
1
3 leases and ports 3 to 8 given
1
lease each. After that, no port could have its
leases increased because the filter resource is completely used up.
Note: On Allied Telesis switches, IGMP snooping and MLD snooping are enabled by default,
which occupy 2 filter entries. To dedicate
11
9 entries to DHCP snooping, IGMP and
MLD snooping would need to be disabled with disable igmpsnooping and disable
mldsnooping. Disabling these services is not desirable if multicasting is used in the
network.
If other hardware filters are used, they will eat into the filter resource and so your maximum
leases (and also your QoS classifiers) would be reduced.
Example on a Rapier 24i
(2 entries * 2 ports) + (5 entries * 6 ports) = 34 entries
(2 entries * 2 ports) + (5 entries * 6 ports) + 1 = 35 entries
(119 maximum entries) – (34 used) = 85 entries
(119 maximum entries) – (35 used) = 84 entries
X If leases are 2 on ports
1
and 2 but 5 on ports 3 to 8, then the number of
filter resources used is:
X If ARP security is enabled, add
1
:
X So, the number of available filter resources left for other hardware filters,
QoS classifiers or more leases is:
X or if ARP security is enabled, is: