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

2
Numbering and naming ACLs
Each ACL category has a unique range of ACL numbers. When creating an ACL, you must assign it a
number. In addition, you can assign the ACL a name for ease of identification. After creating an ACL with
a name, you cannot rename it or delete its name.
You cannot assign a name to a WLAN ACL or simple ACL.
For an IPv4 basic or advanced ACLs, its ACL number and name must be unique in IPv4, and for an IPv6
basic or advanced ACL, its ACL number and name must be unique in IPv6.
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 includes 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 method, check the rules and their order carefully.
NOTE:
The match order of user-defined or WLAN ACLs can only be config.
• auto—Sorts ACL rules in depth-first order. Depth-first ordering makes sure that any subset of a rule
is always matched before the rule. Table 4 lists the
sequence of tie breakers that depth-first ordering
uses to sort rules for each type of ACL.
Table 1 Sorting ACL rules in depth-first order
ACL cate
g
or
y
Se
q
uence 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
4. VPN instance
5. Protocol number
6. More 0s in the source IP address wildcard mask
7. More 0s in the destination IP address wildcard
8. Narrower TCP/UDP service port number range
9. Rule configured earlier
IPv6 basic ACL
10. VPN instance
11. Longer prefix for the source IP address (a longer prefix means a
narrower IP address range)
12. Rule configured earlier