# Interface Sets for QoS Overview

This topic describes how to use interface sets to configure a set of logical interfaces with the same scheduling and queuing properties.

Interface sets are supported for VLANs, ATM VCs, and IP.

You can use interface sets for various scenarios in a broadband access network. For example, you can use an interface set to configure a local loop with a small number of subscribers. Interface sets are also useful for grouping a large number of subscribers into a particular service class or for defining traffic engineering aggregates for DSLAMs.

## Interface Set Terms

Table 21 lists the terminology used for interface sets

Table 21: Interface Set Terms

Term | Description
--- | ---
Interface set | Set of logical interfaces of the same type: VLAN, ATM VC, and IP. An interface set shares a common parent interface.
Interface superset | Set of QoS interface sets and logical interfaces of the same type. A superset shares a common parent interface.
Parent interface | Logical interface associated with a set. All members of an interface set must be configured under this parent interface, or they cannot join an interface set.
VLAN set | Interface set of VLAN subinterfaces.
VLAN superset | Interface superset that contains VLAN interface sets and VLAN subinterfaces, stacked over a common Ethernet major interface.
ATM VC set | Interface set of ATM 1483 subinterfaces.
Restricted VLAN set | Interface set that is restricted to VLAN subinterfaces sharing a common VLAN ID. The parent of the interface set is an S-VLAN. The VLAN subinterfaces that are members of the interface set must have the same S-VLAN ID as the parent.
Spanning VLAN set | Interface set of VLAN subinterfaces that span S-VLANs. The parent of the interface set is an Ethernet major interface. The member VLAN subinterfaces can have different S-VLAN IDs.
Restricted ATM VC set | Interface set that is restricted to ATM VC subinterfaces sharing a common VPI. The parent of the interface set is a VPI. The ATM VC subinterfaces that are members of the interface set must have the same VPI as the parent.
Spanning ATM VC set | Interface set of ATM VC subinterfaces that span VPIs. The parent of the interface set is an ATM major interface. The member ATM VC subinterfaces can have different VPIs.

#### Related Topics

- Architecture of Interface Sets for QoS
- Configuring Interface Sets for Scheduling and Queuing