Applying a Virtual Channel Group to a Logical Interface

To apply a virtual channel group to a logical interface, include the virtual-channel-group statement at the [edit class-of-service interfaces interface-name unit logical-unit-number] hierarchy level:

For the corresponding physical interface, you must also include the per-unit-scheduler statement at the [edit interfaces interface-name] hierarchy level:

The per-unit-scheduler statement enables one set of output queues for each logical interface configured under the physical interface.

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.

When you apply a virtual channel group to a logical interface, the software creates a set of eight queues for each of the virtual channels in the group.

If you apply a virtual channel group to multiple logical interfaces, the software creates a set of eight queues on each logical interface. The virtual channel names listed in the group are used on all the logical interfaces. We recommend specifying the scheduler and shaping rates in the virtual channel configuration in terms of percentages, rather than absolute rates. This allows you to apply the same virtual channel group to logical interfaces that have different bandwidths.

When you apply a virtual channel group to a logical interface, you cannot include the scheduler-map and shaping-rate statements at the [edit class-of-service interfaces interface-name unit logical-unit-number] hierarchy level. In other words, you can configure a scheduler map and a shaping rate on a logical interface, or you can configure virtual channels on the logical interface, but not both.

If you configure multiple logical interfaces on a single physical interface, each logical interface is guaranteed an equal fraction of the physical interface bandwidth:

If one or more logical interfaces do not completely use their allocation, the other logical interfaces share the excess bandwidth equally.

If you configure multiple virtual channels on a logical interface, they are each guaranteed an equal fraction of the logical interface bandwidth:

If you configure a shaper on a virtual channel, the shaper limits the maximum bandwidth transmitted by that virtual channel. Virtual channels without a shaper can use the full logical interface bandwidth. If there are multiple unshaped virtual channels, they share the available logical interface bandwidth equally.

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