# Configuring Traffic Classes That Define Service Levels

The router supports up to eight global traffic classes. Each traffic class can appear in only one traffic-class group. If not explicitly added to a traffic-class group, the traffic class is considered to be ungrouped.

To configure a traffic class:

1. Create a traffic class by assigning a name that represents the type of service and enter Traffic Class Configuration mode.
   host1(config)#traffic-class low-loss1 host1(config-traffic-class)#

   The traffic class name can be up to 31 characters. It cannot include spaces.

2. (Optional) Specify strict-priority scheduling across the fabric for queues in the traffic class.
   host1(config-traffic-class)#fabric-strict-priority
3. (Optional) For Juniper Networks ERX1440, E120 , and E320 Broadband Services Routers, specify the relative weight for queues in the traffic class in the fabric.
   host1(config-traffic-class)#fabric-weight 12

   Fabric weight controls the bandwidth of fabric queues associated with the traffic class. It does not control the weight of egress queues associated with the traffic class. If multiple traffic classes are strict priority, the fabric weight determines which class gets more bandwidth.

   The weight value is in the range 1–63. The default is 8. Zero is not a valid weight.

#### Related Documentation

- Monitoring Traffic Classes and Traffic-Class Groups for Defined Levels of Service
- fabric-strict-priority
- fabric-weight
- traffic-class