Multicast and Routing Guide K/KA/KB.15.15

8 Route Policy
For general information about route policy, see “Route policy overview” (page 212).
Using prefix lists
Prefix lists are named lists of route prefixes. They are used to match routes for inclusion in or
exclusion from route policies.
Creating prefix list entries
A prefix list can include one or more rules, each defined by a sequence number, permit or deny
instruction, prefix, and range of allowed prefix lengths.
Syntax:
[no] [ ip | ipv6 prefix-list name ] [seq seq-num] [ permit | deny
prefix /prefix-length ] [ge min-length] [le max-length]
Enters a route prefix into a prefix list.
[ ip | ipv6 ] Specifies a list of either IPv4 (IP) or IPv6 prefixes.
name Specifies the name of the prefix list to which this
prefix will be added. If the named list does not
exist, this command creates it.
To add a prefix to an existing list, specify the name
of that list.
seq seq-num Optionally specifies a sequence number for the
entry.
permit Permits the prefix when a successful match is made.
deny Denies the prefix when a successful match is made.
prefix/prefix-length Specifies an IPv4 or IPv6 network prefix and its
mask length, in CIDR notation. For example:
10.1.4.1/24.
ge min-length Specifies a minimum mask length of the prefix to
match. min-length must have a value between
1 and 32 for IPv4, or a value between 1 and 128
for IPv6.
This value must be greater than or equal to
prefix-length. If this optional parameter is not
specified, its value defaults to prefix-length.
le max-length Specifies a maximum mask length of the prefix to
match. max-length must have a value between
1 and 32 for IPv4, or a value between 1 and 128
for IPv6.
This value must be greater than or equal to
min-length. If this optional parameter is not
specified, its value defaults to prefix-length.
(If you have specified a value for min-length
that is greater than prefix-length , you must
explicitly specify le with a max-length value
that is greater than or equal to min-length.)
Using prefix lists 205