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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Chapter 42 Configuring IP Unicast Routing Configuring Protocol-Independent Features
• The switch supports QoS DSCP and IP precedence matching in PBR route maps, with these
limitations:
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You cannot apply QoS DSCP mutation maps and PBR route maps to the same interface.
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You cannot configure DSCP transparency and PBR DSCP route maps on the same switch.
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When you configure PBR with QoS DSCP, you can set QoS to be enabled (by entering the mls
qos global configuration command) or disabled (by entering the no mls qos command). When
QoS is enabled, to ensure that the DSCP value of the traffic is unchanged, you should configure
DSCP trust state on the port where traffic enters the switch by entering the mls qos trust dscp
interface configuration command. If the trust state is not DSCP, by default all nontrusted traffic
would have the DSCP value marked as 0.
Enabling PBR
By default, PBR is disabled on the switch. To enable PBR, you must create a route map that specifies
the match criteria and the resulting action if all of the match clauses are met. Then, you must enable PBR
for that route map on an interface. All packets arriving on the specified interface matching the match
clauses are subject to PBR.
PBR can be fast-switched or implemented at speeds that do not slow down the switch. Fast-switched
PBR supports most match and set commands. PBR must be enabled before you enable fast-switched
PBR. Fast-switched PBR is disabled by default.
Packets that are generated by the switch, or local packets, are not normally policy-routed. When you
globally enable local PBR on the switch, all packets that originate on the switch are subject to local PBR.
Local PBR is disabled by default.
Note To enable PBR, the switch or stack master must be running the IP services feature set.
Beginning in privileged EXEC mode, follow these steps to configure PBR:
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 route-map map-tag [permit] [sequence number]Define any route maps used to control where packets are
output, and enter route-map configuration mode.
• map-tag—A meaningful name for the route map. The ip
policy route-map interface configuration command uses
this name to reference the route map. Multiple route maps
might share the same map tag name.
• (Optional) If permit is specified and the match criteria
are met for this route map, the route is policy-routed as
controlled by the set actions.
Note The route-map deny statement is not supported in
PBR route maps to be applied to an interface.
• sequence number (Optional)— Number that shows the
position of a new route map in the list of route maps
already configured with the same name.