H3C S7500E Series Ethernet Switches Operation Manual

Operation Manual – ACL
H3C S7500E Series Ethernet Switches Chapter 1 ACL Overview
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1.2.2 IPv4 ACL Naming
When creating an IPv4 ACL, you can specify a unique name for it. Afterwards, you can
identify the ACL by its name.
An IPv4 ACL can have only one name. Whether to specify a name for an ACL is up to
you. After creating an ACL, you cannot specify a name for it, nor can you change or
remove the name of the ACL.
 Note:
The name of an IPv4 ACL must be unique among IPv4 ACLs. However, an IPv4 ACL
and an IPv6 ACL can share the same name.
1.2.3 IPv4 ACL Match Order
An ACL consists of multiple rules, each of which specifies different matching criteria.
These criteria may have overlapping or conflicting parts. This is where the order in
which a packet is matched against the rules comes to rescue.
Two match orders are available for IPv4 ACLs:
z config: where packets are compared against ACL rules in the order in which they
are configured.
z auto: where depth-first match is performed. The term depth-first match has
different meanings for different types of ACLs.
I. Depth-first match for a basic IPv4 ACL
The following shows how your switch performs depth-first match in a basic IPv4 ACL:
1) Sort rules by VPN instance first and compare packets against the rule configured
with a VPN instance.
2) In case of a tie, sort rules by source IP address wildcard first and compare packets
against the rule configured with more zeros in the source IP address wildcard.
3) If two rules are present with the same number of zeros in their source IP address
wildcards, compare packets against the rule configured first prior to the other.
II. Depth-first match for an advanced IPv4 ACL
The following shows how your switch performs depth-first match in an advanced IPv4
ACL:
1) Sort rules by VPN instance first and compare packets against the rule configured
with a VPN instance.