Cisco ASR 9000 Series Routing Configuration Manual page 581

Implementing Routing Policy
address. The mask length, if present, is a nonnegative decimal integer in the range from 0 to 32 (0 to 128 for
IPv6) following the address and separated from it by a slash. The optional minimum matching length follows
the address and optional mask length and is expressed as the keyword ge (mnemonic for greater than or equal
to), followed by a nonnegative decimal integer in the range from 0 to 32 (0 to 128 for IPv6). The optional
maximum matching length follows the rest and is expressed by the keyword le (mnemonic for less than or
equal to), followed by yet another nonnegative decimal integer in the range from 0 to 32 (0 to 128 for IPv6).
A syntactic shortcut for specifying an exact length for prefixes to match is the eq keyword (mnemonic for
equal to).
If a prefix match specification has no mask length, then the default mask length is 32 for IPv4 and 128 for
IPv6. The default minimum matching length is the mask length. If a minimum matching length is specified,
then the default maximum matching length is 32 for IPv4 and 128 for IPv6. Otherwise, if neither minimum
nor maximum is specified, the default maximum is the mask length.
The prefix-set itself is a comma-separated list of prefix match specifications. The following are examples:
prefix-set legal-ipv4-prefix-examples
10.0.1.1,
10.0.2.0/24,
10.0.3.0/24 ge 28,
10.0.4.0/24 le 28,
10.0.5.0/24 ge 26 le 30,
10.0.6.0/24 eq 28,
10.0.7.2/32 ge 16 le 24,
10.0.8.0/26 ge 8 le 16
end-set
prefix-set legal-ipv6-prefix-examples
2001:0:0:1::/64,
2001:0:0:2::/64 ge 96,
2001:0:0:2::/64 ge 96 le 100,
2001:0:0:2::/64 eq 100
end-set
The first element of the prefix-set matches only one possible value, 10.0.1.1/32 or the host address 10.0.1.1.
The second element matches only one possible value, 10.0.2.0/24. The third element matches a range of prefix
values, from 10.0.3.0/28 to 10.0.3.255/32. The fourth element matches a range of values, from 10.0.4.0/24 to
10.0.4.240/28. The fifth element matches prefixes in the range from 10.0.5.0/26 to 10.0.5.252/30. The sixth
element matches any prefix of length 28 in the range from 10.0.6.0/28 through 10.0.6.240/28. The seventh
element matches any prefix of length 32 in the range 10.0.[0..255].2/32 (from 10.0.0.2/32 to 10.0.255.2). The
eighth element matches any prefix of length 26 in the range 10.[0..255].8.0/26 (from 10.0.8.0/26 to
10.255.8.0/26).
The following prefix-set consists entirely of invalid prefix match specifications:
prefix-set ILLEGAL-PREFIX-EXAMPLES
10.1.1.1 ge 16,
10.1.2.1 le 16,
10.1.3.0/24 le 23,
10.1.4.0/24 ge 33,
10.1.5.0/25 ge 29 le 28
end-set
Neither the minimum length nor maximum length is valid without a mask length. For IPv4, the minimum
length must be less than 32, the maximum length of an IPv4 prefix. For IPv6, the minimum length must be
less than 128, the maximum length of an IPv6 prefix. The maximum length must be equal to or greater than
the minimum length.
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.3.x
Routing Policy Language Overview
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