Net Optics Smart Filtering none - Manual (Page 42)

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Director
Be aware of these similar pairs of commands:
filter discard • clears the pending filter list, while filter clear clears the CAM
filter list • shows the pending filter list, while filter running shows the CAM
filter commit • copies the pending filter list to the CAM, while filter sync copies the CAM to the pending filter list
Pending filter list
Address Filter
1
2
filter discard to clear
filter list to view contents
CAM
Address Filter
1
2
filter clear to clear
filter running to view contents
filter commit
filter sync
Pairs of similar filter commands Figure 45:
User interactions
When multiple users are logged into Director at the same time, each user has a separate pending filter list in which to
create filter configurations. However, there is only one CAM, so any time a user executes a commit or filter commit
command, the CAM takes on the filter configuration from that user's pending filter list, and those become the active
filters on Director. For this reason, it is a good idea to use a filter sync to get the current contents of the CAM before
adding or modifying filters; that way, the filters that you don't touch remain unaffected after you commit.
Filter capacity
The capacity of Director's filtering function is roughly 1,000 filter elements per chassis, where a filter element is
a port list or a filter parameter. For example, filter add in_ports=n1.1-n1.7 ip_proto=6 vlan=100 action=redir
redir_ports=m.1-m.5,m.10 has four filter elements:
in_ports=n1.1-n1.7 1.
ip_proto=6 2.
vlan=100 3.
redir_ports=m.1-m.5,m.10 4.
Counting filter elements is only a rough gauge of filter utilization, and is not recommended. Instead, examine the
pending filter list or CAM contents with filter list and filter running commands. The CAM has 512 locations, so
the number of filter entries or filter IDs is an indication of how much filtering capacity has been utilized. For example,
if the highest filter ID is 256, then half of the filter capacity is utilized. The actual capacity may exceed 1,000 filter
elements because one CAM location can contain multiple filter elements. However, be aware that IPv6 addresses (when
available) require additional CAM space and therefore fill the CAM more quickly than IPv4 addresses.