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Defining CoS Schedulers and Scheduler Maps (CLI Procedure)

 

You use schedulers to define the class-of-service (CoS) properties of output queues. These properties include the amount of interface bandwidth assigned to the queue, the size of the memory buffer allocated for storing packets, the priority of the queue, and the drop profiles associated with the queue.

You associate the schedulers with forwarding classes by means of scheduler maps. You can then associate each scheduler map with an interface, thereby configuring the queues and packet schedulers that operate according to this mapping.

Note

On EX Series switches, you cannot configure a scheduler map on an individual interface that is a member of a link aggregation group (LAG). Instead, you must configure the scheduler map on the LAG itself (that is, on the aggregated Ethernet (ae) interface).

You can associate up to four user-defined scheduler maps with an interface.

This topic describes:

Configuring a Scheduler and a Scheduler Map

You can define the properties for an output queue by configuring a scheduler. You can then define a scheduler map to associate a forwarding class with a scheduler.

To configure a scheduler and a scheduler map:

  1. Create a scheduler, and assign one or more output queue properties to it:
    [edit class-of-service]

    user@switch# set schedulers scheduler-name output-queue-properties
     

    For various properties that you can define for an output queue, see the schedulers hierarchy.



  2. Configure a scheduler map that associates the scheduler with the forwarding class:
    [edit class-of-service]

    user@switch# set scheduler-maps map-name forwarding-class class-name scheduler scheduler-name
     


Assigning a Scheduler Map to Interfaces

After defining a scheduler map, you can assign the scheduler map to one or more interfaces. You can also assign the scheduler map to multiple interfaces by using a wildcard representation of the interface or Virtual Chassis Ports (VCPs).

Following are sample syntaxes and examples for assigning a scheduler map to a single or to multiple interfaces:

  • To assign the scheduler map to one interface:

    [edit class-of-service interfaces]

    user@switch# set interface-name scheduler-map map-name
  • To assign the scheduler map to more than one interface, you can use a wildcard representation of the interface:

    [edit class-of-service interfaces]

    user@switch# set wild-card-representation-of-interface-name scheduler-map map-name

    For example, following is the configuration to assign the be-map scheduler map to all Gigabit Ethernet interfaces (ge-*):

    [edit class-of-service interfaces]

    user@switch# set ge-* scheduler-map be-map
  • To assign the scheduler map to all VCPs:

    [edit class-of-service interfaces]

    user@switch# set wild-card-representation-of-vcp scheduler-map map-name
    Note

    You can assign a scheduler map to a VCP only on EX4200, EX4300 or EX4500 switches that are members of Virtual Chassis composed exclusively either of EX4200 switches, EX4300 switches or of EX4500 switches, or that are members of a mixed Virtual Chassis composed of EX4200, EX4300, and EX4500 switches.

    For example, following is the configuration to assign the be-map scheduler map to all VCPs:

    [edit class-of-service interfaces]

    user@switch# set vcp-* scheduler-map be-map

Assigning Scheduler Maps to Interfaces on EX8200 Line Cards That Include Oversubscribed Ports

Some line cards available for Juniper Networks EX8200 Ethernet Switches include oversubscribed ports that are combined in logical port groups that share bandwidth. These oversubscribed ports handle traffic differently than ports that provide continuous line-rate bandwidth. You might need to configure CoS queues differently for oversubscribed ports than for line-rate ports. For more information about EX8200 line cards that include oversubscribed ports, see Understanding CoS Queues on EX8200 Line Cards That Include Oversubscribed Ports.

For interfaces on oversubscribed EX8200 line cards, you use the same procedure to configure CoS schedulers as you do for other interfaces. However, you must assign the same scheduler map to all the interfaces in a port group. When you assign a scheduler map to one interface in a port group, you do not need to assign the scheduler map to the remaining interfaces in the port group. The switch automatically uses that scheduler map for all the interfaces in the port group when you bring the interfaces up. Therefore, you do not need to assign the scheduler map to the remaining interfaces in that port group.

If you assign different scheduler maps to different interfaces in a port group, you do not receive an error when you commit the configuration. Instead, an error is logged in the system log. When you bring an interface in the port group up, the default scheduler map is assigned to all interfaces in the port group. If you assign a scheduler map to an interface that is down and if that scheduler map is different from the scheduler map being used by the currently operating interfaces in the port group, then the default scheduler map is used by all interfaces in the port group, even the currently operating ones, when you bring the interface up.

To assign a scheduler map to a port group, assign a scheduler map to at least one interface in the port group:

[edit class-of-service interfaces]

user@switch# set interface-name scheduler-map map-name

Considering that the xe-0/0/2 interface is part of a port group, following is the configuration to assign a scheduler map named ef-map to a port group that contains xe-0/0/2:

[edit class-of-service interfaces]

user@switch# set xe-0/0/2 scheduler-map ef-map