Classifiers and Rewrite Rules

ACX Series Routers and EX Series switches Running Junos OS

Most ACX Series routers and EX Series switches that run Junos OS support applying classifier and rewrite rules at the global level and physical interface levels.

At a global level, you can define EXP classification.

At a physical interface level, you can define the following features:

• DSCP, DSCP-IPV6, and IPv4 precedence classifiers

• DSCP, DSCP-IPV6, and IPv4 precedence rewrites

• IEEE 802.1p and IEEE 802.1ad classifiers (inner and outer)

• IEEE 802.1p and IEEE 802.1ad rewrites (outer)

The IEEE 802.1ad classifier uses IEEE 802.1p and DEI bits together.

Note:

You cannot configure both IEEE 802.1p and IEEE 802.1ad classifiers together at the physical interface level.

The ACX6360 router does not support rewrite rules or Layer 2 (IEEE802.1p and IEEE802.1ad) classifiers.

At a logical interface level, you can define fixed classification and EXP rewrites.

To configure global EXP classifiers, include the classfiers exp classifier-name statement at the [edit class-of-service system-defaults] hierarchy level.

To configure classifiers or rewrite rules at the physical interface, include either the classifiers statement or the rewrite-rules statement at the [edit class-of-service interfaces interface-name] hierarchy level.

To configure fixed classifiers at the logical interface, include the forwarding-class fc] or the rewrite-rules statement at the [edit class-of-service interfaces interface-name unit number] hierarchy level.

To configure EXP rewrite at the logical interface, include the [edit class-of-service interfaces interface-name unit number rewrite-rules exp rewrite-rule] statement.

To display classifiers configured under system-defaults, enter the show class-of-service system-defaults command.

To display classifiers and rewrite rules bound to physical interfaces, enter the show class-of-service interfaces interface-name command.

ACX Series Routers Running Junos OS Evolved

ACX Series routers that run Junos OS Evolved support applying classifier and rewrite rules at the logical interface level.

ACX Series routers that run Junos OS Evolved additionally support applying multiple classifier and rewrite rules simultaneously to a single logical interface. For example, the following configuration is valid:

When you apply multiple classifier rewrite rules to a logical interface, if a packet has multiple headers, there can be ambiguity in which classifier or rewrite rule to select. Table 1 lists the classifier the logical interface selects in different scenarios. Table 2 lists the rewrite rule the logical interface selects in different scenarios.

Table 1: Classifier selection from multiple classifiers

Ingress packet	Configured families on the interface	Classifiers applied to the interface	Selected classifier profile
L3 packet with IPv4 header	IPv4, IPv6	DSCP plus any other	DSCP classifier based on IPv4 forwarding
L3 packet with IPv4 header	IPv4, IPv6	INET precedence plus any other	INET precedence classifier based on IPv4 forwarding
L3 packet with IPv6 header	IPv4, IPv6	DSCP-IPv6 plus any other	DSCP-IPv6 classifier based on IPv6 forwarding
VLAN tagged L3 packet	L3, MPLS	Custom IEEE-802.1ad, default L3 (DSCP, DSCP-IPv6, INET precedence)	Custom IEEE-802.1ad classifier
VLAN tagged L3 packet	L3, MPLS	Custom IEEE-802.1ad, custom L3	Custom L3 classifier
VLAN tagged L3 packet	L3, MPLS	Custom IEEE-802.1ad, default EXP	Custom IEEE-802.1ad classifier
VLAN tagged L3 packet	L3, MPLS	Custom IEEE-802.1ad, custom EXP	Custom EXP classifier

Table 2: Rewrite rule selection from multiple rewrite rules

Ingress packet	Configured families on the interface	Rewrite rules applied to the interface	Selected rewrite rule
L3 packet with IPv4 header	IPv4, IPv6	DSCP plus any other	DSCP rewrite rule based on IPv4 forwarding
L3 packet with IPv4 header	IPv4, IPv6	INET precedence plus any other	INET precedence rewrite rule based on IPv4 forwarding
L3 packet with IPv6 header	IPv4, IPv6	DSCP-IPv6 plus any other	DSCP-IPv6 rewrite rule based on IPv4 or IPv6 forwarding