H3C Technologies H3C S10500 Series Switches - Manual (Page 10)

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For an Ethernet frame header ACL, the ACL number and name must be globally unique. For an IPv4 basic
or advanced ACLs, its ACL number and name must be unique among all IPv4 ACLs, and for an IPv6
basic or advanced ACL, its ACL number and name must be unique among all IPv6 ACLs. You can assign
an IPv4 ACL and an IPv6 ACL the same number and name.
Match order
The rules in an ACL are sorted in a specific order. When a packet matches a rule, the device stops the
match process and performs the action defined in the rule. If an ACL contains overlapping or conflicting
rules, the matching result and action to take depend on the rule order.
The following ACL match orders are available:
• config—Sorts ACL rules in ascending order of rule ID. A rule with a lower ID is matched before a
rule with a higher ID. If you use this approach, carefully check the rules and their order.
• auto—Sorts ACL rules in depth-first order. Depth-first ordering ensures that any subset of a rule is
always matched before the rule.
Table 1 lists the sequence of tie breakers that depth-first ordering
uses to sort rules for each type of ACL.
Table 1 Sort ACL rules in depth-first order
ACL category Sequence of tie breakers
IPv4 basic ACL
1. VPN instance
2. More 0s in the source IP address wildcard (more 0s means a narrower IP
address range)
3. Rule configured earlier
IPv4 advanced ACL
1. VPN instance
2. Specific protocol type rather than IP (IP represents any protocol over IP)
3. More 0s in the source IP address wildcard mask
4. More 0s in the destination IP address wildcard
5. Narrower TCP/UDP service port number range
6. Rule configured earlier
IPv6 basic ACL
1. VPN instance
2. Longer prefix for the source IP address (a longer prefix means a narrower IP
address range)
3. Rule configured earlier
IPv6 advanced ACL
1. VPN instance
2. Specific protocol type rather than IP (IP represents any protocol over IPv6)
3. Longer prefix for the source IPv6 address
4. Longer prefix for the destination IPv6 address
5. Narrower TCP/UDP service port number range
6. Rule configured earlier
Ethernet frame header ACL
1. More 1s in the source MAC address mask (more 1s means a smaller MAC
address)
2. More 1s in the destination MAC address mask
3. Rule configured earlier