Details how queuing policies behave on subinterfaces, including supported policy actions, queue handling, and operational considerations for applying QoS controls at subinterface level.
| Feature Name |
Release Information |
Feature Description |
|---|---|---|
| Egress queuing on L2 subinterfaces |
Release 26.2.1 | Introduced in this release on: Fixed Systems (8700 [ASIC: K100], 8010 [ASIC: A100]) You can now apply egress queuing policies on Layer 2 subinterfaces to allocate dedicated VOQs for subinterface traffic. This enhancement enables independent traffic management for Layer 2 and Layer 3 services that share the same physical or bundle interface. This capability provides more granular bandwidth control for multi-customer services, such as such as cloud, content-provider, VPWS, and so on. This release also adds child-level shaping support for Layer 2 subinterface queuing. |
| Subinterface Queueing Policy |
Release 26.1.1 | Introduced in this release on: Centralized Systems (8400 [ASIC: K100]) (select variants only*) *This feature is now supported on the Cisco 8404-SYS-D routers. |
| Subinterface Queueing Policy |
Release 25.4.1 |
Introduced in this release on: Fixed Systems (8010 [ASIC: A100])(select variants only*) *This feature is supported on:
|
| Subinterface Queueing Policy |
Release 25.1.1 | Introduced in this release on: Fixed Systems (8010 [ASIC: A100])(select variants only*) *This feature is supported on Cisco 8011-4G24Y4H-I routers. |
| Subinterface Queueing Policy |
Release 24.4.1 | Introduced in this release on: Fixed Systems (8700) (select variants only*) You can manage traffic flows with fine granularity by configuring QoS policies at the subinterface level. *This functionality is now supported on Cisco 8712-MOD-M routers. |
| Subinterface Queueing Policy |
Release 24.3.1 |
Introduced in this release on: Modular Systems (8800 [LC ASIC: P100]) (select variants only*), Fixed Systems (8200) (select variants only*), Fixed Systems (8700 (P100, K100)) (select variants only*)Modular Systems (8800 [LC ASIC: P100]) , Fixed Systems (8200) , Fixed Systems (8700 (P100, K100)) (select variants only*) You can manage traffic flows with fine granularity by configuring QoS policies at the subinterface level. *This feature is supported on:
|
| Subinterface Queueing Policy |
Release 24.2.11 |
Introduced in this release on: Modular Systems (8800 [LC ASIC: P100]) (select variants only*) To manage traffic flows with fine granularity, you can configure QoS policies at the subinterface level. Also, with QoS support on mixed Layer 2 and Layer 3 subinterfaces under the same main interface, you can ensure that multiple traffic types with varying QoS requirements coexist on a single main physical interface. *This feature is supported on 88-LC1-36EH. |
A subinterface uses the main interface VOQs by default. When you apply an egress queuing policy, the router allocates a dedicated set of VOQs—4 or 8, depending on the chassis-wide VOQ mode you selected earlier. Each subinterface can host up to three QoS policies (ingress, egress marking, and egress queuing). If you remove the egress-queuing policy later, its VOQs are released and the subinterface traffic reverts to the main interface queues.
Use this table to understand the limits and defaults that apply after a policy is attached.
| Attribute |
8xVOQ |
4xVOQ |
|---|---|---|
| VOQs per sub-interface |
8 |
4 |
| Default hierarchy |
P1 + P2 + 6 PN |
P1 + P2 + 2 PN |
P1—one hardware queue reserved for the single most critical class (typically TC 7).
P2—one queue for the next-most-critical class (typically TC 6).
PN (normal priority queues):
In 8×VOQ mode—one queue each for TC5, TC4, TC3, TC2, TC1, and TC0 (six PN queues).
In 4×VOQ mode—one queue each for TC1 and TC0 (two PN queues)
A line card has a fixed pool of VOQs and scheduler state blocks, so there is a limit to the number of policies you can deploy before resources are exhausted. To monitor the remaining VOQ and scheduler resources by viewing packet and byte counts per traffic class, as well as drops, which can indicate resource constraints, run the show controllers npu stats voq command.
Next steps:
-
Decide which traffic classes need their own scheduler or shaper.
-
Configure an egress queuing policy that defines those actions.
-
Apply the policy with service-policy output <policy-name> under the subinterface.
-
Verify that the policy is active with show qos interface .