R2511-HP MSR Router Series ACL and QoS Configuration Guide(V5)

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ACL cate
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uence of tie breakers
IPv6 advanced ACL
13. VPN instance
14. Protocol number
15. Longer prefix for the source IPv6 address
16. Longer prefix for the destination IPv6 address
17. Narrower TCP/UDP service port number range
18. Rule configured earlier
Ethernet frame header ACL
19. More 1s in the source MAC address mask (more 1s means a smaller
MAC address)
20. More 1s in the destination MAC address mask
21. Rule configured earlier
A wildcard mask, also called an inverse mask, is a 32-bit binary and represented in dotted
decimal notation. In contrast to a network mask, the 0 bits in a wildcard mask represent "do care"
bits, and the 1 bits represent "don’t care" bits. If the "do care" bits in an IP address are identical
to the "do care" bits in an IP address criterion, the IP address matches the criterion. All "don’t care"
bits are ignored. The 0s and 1s in a wildcard mask can be noncontiguous. For example,
0.255.0.255 is a valid wildcard mask.
NOTE:
A
simple ACL can include only one rule.
Rule comments and rule range remarks
Add a comment about an ACL rule to make it easy to understand. The rule comment appears below the
rule statement.
In addition, add a rule range remark to indicate the start or end of a range of rules created for the same
purpose.
Rule numbering
ACL rules can be manually numbered or automatically numbered. This section describes how automatic
ACL rule numbering works.
Rule numbering step
If you do not assign an ID to the rule you are creating, the system automatically assigns it a rule ID. The
rule numbering step sets the increment by which the system automatically numbers rules. For example, the
default ACL rule numbering step is 5. If you do not assign IDs to rules you are creating, they are
automatically numbered 0, 5, 10, 15, and so on. The wider the numbering step, the more rules you can
insert between two rules.
By introducing a gap between rules rather than contiguously numbering rules, you have the flexibility of
inserting rules in an ACL. This feature is important for a config order ACL, where ACL rules are matched
in ascending order of rule ID.
Automatic rule numbering and renumbering
The ID automatically assigned to an ACL rule takes the nearest higher multiple of the numbering step to
the current highest rule ID, starting with 0.