Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Applying QOS to subinterface and then to physical interface

Can be service policy applied to subinterface and then to physical interface aggregating this all subinterfaces (Eth)?

Are there any limitations about it.


Applying QOS to subinterface and then to physical interface

Hi Idan,

there are a couple of thing stated by Cisco about these sort of applications:

If you apply a policy with the police command to both the interface and the subinterface, only the subinterface policer is active for the traffic that matches the class.

Cisco IOS logical interfaces do not inherently support a state of congestion and do not support the direct application of a service policy that applies a queueing method. Instead, you first need to apply shaping to the subinterface using either generic traffic shaping (GTS) or class-based shaping.

In other words, you must configure a hierarchical policy with the shape command at the parent level. Use the bandwidth command for CBWFQ, or the priority command for Low Latency Queueing (LLQ) at lower levels. Class-based shaping limits the output rate and (we can assume) leads to a congested state on the logical subinterface. The subinterface than applies "backpressure," and Cisco IOS begins queueing the excess packets that are held by the shaper.

Hope it Helps,


Hope it Helps, Soroush.