ACL Filter Policy Overview
482 Router Configuration Guide
Filter Policy Advanced Topics
Match-list for Filter Policies
Figure 16 depicts an approach to implement logical OR on a list of matching criterion (IPv4
address prefixes in this example) in one or more filter policies prior to introduction of match
list.
Figure 16: IOM/CPM Filter Policy using Individual Address Prefixes
An operator has to create one entry for each address prefix to execute a common action. Each
entry defines a match on a unique address prefix from the list plus any other additional match
criteria and the common action. If the same set of address prefixes needs to be used in another
IOM/linecard, or CPM filter policy, an operator again needs to create one entry for each
address prefix of the list in those filter policies. Same procedure applies (not shown above) if
another action needs to be performed on the list of the addresses within the same filter policy
(when for example specifying different additional match criteria). This process can introduce
large operational overhead, especially when a list contains many elements or/and needs to be
reused multiple times across one or more filter policies.
Match list for CPM and IOM/FP filter policies are introduced to eliminate above operational
complexity by simplifying the IOM/FP and CPM filter policy management on a list of a
match criterion. Instead of defining multiple filter entries in any given filter, an operator can
now group same type of the matching criteria into a single filter match list, and then use that
list as a match criterion value, thus requiring only single filter policy entry per each unique
action. The same match list can be used in one or more IOM/linecard filter policies as well as
CPM filter policies.
The match lists further simplify management and deployment of the policy changes. A
change in a match-list content is automatically propagated across all policies employing that
list in their match criteria, thus only a single configuration change is required to trigger policy
changes when a list is used by multiple entries in one or more filter policies.
Entry K+1
+1: match IPv4 Prefix 1
Entry K+2
: match IPv4 Prefix 2
Entry K+N
match IPv4 Prefix N
CPM Filter
IOM Filters
OSSG729
Entry M+1
match IPv4 Prefix 1
Entry M+2
match IPv4 Prefix 2
Entry M+N
match IPv4 Prefix N
IPv4 Prefix 1
IPv4 Prefix 2
IPv4 Prefix N
To Next Page
Loading...
