Classify Packets by Egress Interface
On supported platforms, you can classify unicast and multicast packets based on the egress interface. For unicast traffic, you can also use a multifield filter, but only egress interface classification applies to multicast traffic as well as unicast traffic. If you configure egress classification of an interface, you cannot perform DSCP rewrites on the interface. By default, the system does not perform any classification based on the egress interface.
To enable packet classification by the egress interface, you first configure a forwarding
class map and one or more queue numbers for the egress interface at the [edit
class-of-service forwarding-class-map
forwarding-class-map-name] hierarchy level:
[edit class-of-service]
forwarding-class-map forwarding-class-map-name {
class class-name queue-num queue-number [ restricted-queue queue-number ];
}
If you configure an output forwarding class map associating a forwarding class with a
queue number, this map is not supported on multiservices link services IQ
(lsq-) interfaces.
Once the forwarding class map has been configured, you apply the map to the logical
interface by using the output-forwarding-class-map statement at the
[edit class-of-service interfaces interface-name unit
logical-unit-number ] hierarchy level:
[edit class-of-service interfaces interface-name unit logical-unit-number] output-forwarding-class-map forwarding-class-map-name;
All parameters relating to the queues and forwarding class must be configured as well. For more information about configuring forwarding classes and queues, see Configuring a Custom Forwarding Class for Each Queue.
You cannot apply a rewrite rule and output forwarding class map to the same logical interface (unit). Although a warning is issued, the CLI does not prevent this configuration. An error message appears when you attempt to commit the configuration.
This example shows how to configure an interface-specific forwarding-class map named
FCMAP1 that restricts queues 5 and 6 to different queues on
four-queue systems and then applies FCMAP1 to unit 0
of interface ge-6/0/0:
[edit class-of-service]
forwarding-class-map FCMAP1 {
class FC1 queue-num 6 restricted-queue 3;
class FC2 queue-num 5 restricted-queue 2;
class FC3 queue-num 3;
class FC4 queue-num 0;
class FC3 queue-num 0;
class FC4 queue-num 1;
}
[edit class-of-service]
interfaces {
ge-6/0/0 unit 0 {
output-forwarding-class-map FCMAP1;
}
}
Note that without the restricted-queue option in
FCMAP1, the example would assign FC1 and
FC2 to queues 2 and 1, respectively, on a system restricted to four
queues.
Use the show class-of-service forwarding-class
forwarding-class-map-name command to display the
forwarding-class map queue configuration:
user@host> show class-of-service forwarding-class FCMAP2 Forwarding class ID Queue Restricted queue FC1 0 6 3 FC2 1 5 2 FC3 2 3 3 FC4 3 0 0 FC5 4 0 0 FC6 5 1 1 FC7 6 6 2 FC8 7 7 3
Use the show class-of-service interface
interface-name command to display the forwarding-class
maps (and other information) assigned to a logical interface:
user@host> show class-of-service interface ge-6/0/0 Physical interface: ge-6/0/0, Index: 128 Queues supported: 8, Queues in use: 8 Scheduler map: <default>, Index: 2 Input scheduler map: <default>, Index: 3 Chassis scheduler map: <default-chassis>, Index: 4 Logical interface: ge-6/0/0.0, Index: 67 Object Name Type Index Scheduler-map sch-map1 Output 6998 Scheduler-map sch-map1 Input 6998 Classifier dot1p ieee8021p 4906 forwarding-class-map FCMAP1 Output 1221 Logical interface: ge-6/0/0.1, Index 68 Object Name Type Index Scheduler-map <default> Output 2 Scheduler-map <default> Input 3 Logical interface: ge-6/0/0.32767, Index 69 Object Name Type Index Scheduler-map <default> Output 2 Scheduler-map <default> Input 3
Platform-Specific Forwarding Class Behavior
Use Feature Explorer to confirm platform and release support for specific features.
Use the following table to review platform-specific behaviors for your platform:
| Platform | Difference |
|---|---|
|
MX Series |
On an MX Series router that contains MPCs and MS-DPCs, multicast packets are dropped on the router and not processed properly if the router contains MLPPP LSQ logical interfaces that function as multicast receivers and if the network services mode is configured as enhanced IP mode on the router. This behavior is expected with LSQ interfaces with enhanced IP mode. In such a scenario, if enhanced IP mode is not configured, multicasting works correctly. However, if the router contains redundant LSQ interfaces and enhanced IP network services mode configured with FIB localization, multicast works properly. |