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Associating the Scheduler Map and a Shaping Rate with a DLCI or VLAN

By default, output scheduling is not enabled on logical interfaces. Logical interfaces without shaping configured share a default scheduler. This scheduler has a committed information rate (CIR) that equals 0. (The CIR is the guaranteed rate.) The default scheduler has a peak information rate (PIR) that equals the physical interface shaping rate.

Logical interface scheduling (also called per-unit scheduling) allows you to enable multiple output queues on a logical interface and associate an output scheduler and shaping rate with the queues. You can configure logical interface scheduling on the following PICs:

For J-series Services Routers only, you can configure per-unit scheduling for virtual channels. For more information, see Configuring Virtual Channels.

For Channelized and Gigabit Ethernet IQ PICs only, you can configure a shaping rate for a VLAN or DLCI and oversubscribe the physical interface by including the shaping-rate statement at the [edit class-of-service traffic-control-profiles] hierarchy level. With this configuration approach, you can independently control the delay-buffer rate, as described in Oversubscribing Interface Bandwidth.

Physical interfaces (for example, t3-0/0/0, t3-0/0/0:0, and ge-0/0/0) support scheduling with any encapsulation type pertinent to that physical interface. For a single port, you cannot apply scheduling to the physical interface if you apply scheduling to one or more of the associated logical interfaces.

For Gigabit Ethernet IQ2 PIC PICs only, you can configure hierarchical traffic shaping, meaning the shaping is performed on both the physical interface and the logical interface. You can also configure input traffic scheduling and shared scheduling. For more information, see Shaping Input and Output Traffic on Ethernet IQ2 Interfaces.

Logical interfaces (for example. t3-0/0/0.0, ge-0/0/0.0, and t1-0/0/0:0.1) support scheduling on DLCIs or VLANs only. Furthermore, logical interface scheduling is not supported on PICs that do not have IQ.

Note: In the JUNOS software implementation, the term logical interfaces generally refers to interfaces you configure by including the unit statement at the [edit interfaces interface-name] hierarchy level. As such, logical interfaces have the logical descriptor at the end of the interface name, as in ge-0/0/0.1 or t1-0/0/0:0.1, where the logical unit number is 1.

Although channelized interfaces are generally thought of as logical or virtual, the JUNOS software sees T3, T1, and NxDS0 interfaces within a channelized IQ PIC as physical interfaces. For example, both t3-0/0/0 and t3-0/0/0:1 are treated as physical interfaces by the JUNOS software. In contrast, t3-0/0/0.2 and t3-0/0/0:1.2 are considered logical interfaces because they have the .2 at the end of the interface names.

Within the [edit class-of-service] hierarchy level, you cannot use the .logical descriptor when you assign properties to logical interfaces. Instead, you must include the unit statement in the configuration. For example:

[edit class-of-service]
user@host# set interfaces t3-0/0/0 unit 0 scheduler-map map1

Table 36 shows the interfaces that support transmission scheduling.

Table 36: Transmission Scheduling Support by Interfaces Type

Interface Type

PIC Type

Supported

Examples
IQ PICs

Physical interfaces

ATM2 IQ

Yes

Example of supported configuration:

[edit class-of-service interfaces at-0/0/0]
scheduler-map map-1;

Channelized interfaces configured on IQ PICs

Channelized DS3 IQ

Yes

Example of supported configuration:

[edit class-of-service interfaces t1-0/0/0:1]
scheduler-map map-1;

Logical interfaces (DLCIs and VLANs only) configured on IQ PICs

Gigabit Ethernet IQ with VLAN tagging enabled

Yes

Example of supported configuration:

[edit class-of-service interfaces ge-0/0/0 unit 1]
scheduler-map map-1;

E3 IQ with Frame Relay encapsulation

Yes

Example of supported configuration:

[edit class-of-service interfaces e3-0/0/0 unit 1]
scheduler-map map-1;

Channelized OC3 IQ with Frame Relay encapsulation

Yes

Example of supported configuration:

[edit class-of-service interfaces t1-1/0/0:1:1 unit 0]
scheduler-map map-1;

Channelized STM1 IQ with Frame Relay encapsulation

Yes

Example of supported configuration:

[edit class-of-service interfaces e1-0/0/0:1 unit 1]
scheduler-map map-1;

Channelized T3 IQ with Frame Relay encapsulation

Yes

Example of supported configuration:

[edit class-of-service interfaces t1-0/0/0 unit 1]
scheduler-map map-1;

Logical interfaces configured on IQ PICs (interfaces that are not DLCIs or VLANs)

E3 IQ PIC with Cisco HDLC encapsulation

No

Example of unsupported configuration:

[edit class-of-service interfaces e3-0/0/0 unit 1]
scheduler-map map-1;

ATM2 IQ PIC with LLC/SNAP encapsulation

No

Example of unsupported configuration:

[edit class-of-service interfaces at-0/0/0 unit 1]
scheduler-map map-1;

Channelized OC12 IQ PIC with PPP encapsulation

No

Example of unsupported configuration:

[edit class-of-service interfaces t1-0/0/0:1 unit 1]
scheduler-map map-1;
Non-IQ PICs

Physical interfaces

T3

Yes

Example of supported configuration:

[edit class-of-service interfaces t3-0/0/0]
scheduler-map map-1;

Channelized OC12 PIC

Channelized OC12

Yes

Example of supported configuration:

[edit class-of-service interfaces t3-0/0/0:1]
scheduler-map map-1;

Channelized interfaces (except the Channelized OC12 PIC)

Channelized STM1

No

Example of unsupported configuration:

[edit class-of-service interfaces e1-0/0/0:1]
scheduler-map map-1;

Logical interfaces

Fast Ethernet

No

Example of unsupported configuration:

[edit class-of-service interfaces fe-0/0/0 unit 1]
scheduler-map map-1;

Gigabit Ethernet

No

Example of unsupported configuration:

[edit class-of-service interfaces ge-0/0/0 unit 0]
scheduler-map map-1;

ATM1

No

Example of unsupported configuration:

[edit class-of-service interfaces at-0/0/0 unit 2]
scheduler-map map-1;

Channelized OC12

No

Example of unsupported configuration:

[edit class-of-service interfaces t3-0/0/0:0 unit 2]
scheduler-map map-1;

To configure transmission scheduling on logical interfaces, perform the following steps:

  1. Enable scheduling on the interface by including the per-unit-scheduler statement at the [edit interfaces interface-name] hierarchy level:
    [edit interfaces interface-name]
    per-unit-scheduler;

    When you include this statement, the maximum number of VLANs supported is 768 on a single-port Gigabit Ethernet IQ PIC. On a dual-port Gigabit Ethernet IQ PIC, the maximum number is 384.

  2. Associate a scheduler with the interface by including the scheduler-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]
    scheduler-map map-name;
  3. Configure shaping on the interface by including the shaping-rate 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]
    shaping-rate rate;

    By default, the logical interface bandwidth is the average of unused bandwidth for the number of logical interfaces that require default bandwidth treatment. You can specify a peak bandwidth rate in bps, either as a complete decimal number or as a decimal number followed by the abbreviation k (1000), m (1,000,000), or g (1,000,000,000). The range is from 1000 through 32,000,000,000 bps.

    For FRF.16 bundles on link services interfaces, only shaping rates based on percentage are supported.

Example: Associating the Scheduler Map Name with a DLCI or VLAN

Associate the scheduler sched-map-logical-0 with logical interface unit 0 on physical interface t3-1/0/0, and allocate 10 Mbps of transmission bandwidth to the logical interface.

Associate the scheduler sched-map-logical-1 with logical interface unit 1 on physical interface t3-1/0/0, and allocate 20 Mbps of transmission bandwidth to the logical interface.

The allocated bandwidth is shared among the individual forwarding classes in the scheduler map. Although these schedulers are configured on a single physical interface, they are independent from each other. Traffic on one logical interface unit does not affect the transmission priority, bandwidth allocation, or drop behavior on the other logical interface unit.

For another example, see the JUNOS Feature Guide.

[edit interfaces]
t3-1/0/0:1 {
encapsulation frame-relay;
per-unit-scheduler;
}
 
[edit class-of-service]
interfaces {
t3-1/0/0:1 {
unit 0 {
scheduler-map sched-map-logical-0;
shaping-rate 10m;
}
unit 1 {
scheduler-map sched-map-logical-1;
shaping-rate 20m;
}
}
}
 
scheduler-maps {
sched-map-logical-0 {
forwarding-class best-effort scheduler sched-best-effort-0;
forwarding-class assured-forwarding scheduler sched-bronze-0;
forwarding-class expedited-forwarding scheduler sched-silver-0;
forwarding-class network-control scheduler sched-gold-0;
}
sched-map-logical-1 {
forwarding-class best-effort scheduler sched-best-effort-1;
forwarding-class assured-forwarding scheduler sched-bronze-1;
forwarding-class expedited-forwarding scheduler sched-silver-1;
forwarding-class network-control scheduler sched-gold-1;
}
 
schedulers {
sched-best-effort-0 {
transmit-rate 4m;
}
sched-bronze-0 {
transmit-rate 3m;
}
sched-silver-0 {
transmit-rate 2m;
}
sched-gold-0 {
transmit-rate 1m;
}
sched-best-effort-1 {
transmit-rate 8m;
}
sched-bronze-1 {
transmit-rate 6m;
}
sched-silver-1 {
transmit-rate 4m;
}
sched-gold-1 {
transmit-rate 2m;
}
}
}
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