# S-VLAN Oversubscription

When you configure S-VLAN subinterfaces over Ethernet interfaces to support dynamic PPPoE subinterfaces, you can take advantage of S-VLAN oversubscription.

The following module combinations support S-VLAN oversubscription:

- GE/FE line module and all of its associated I/O modules
- GE-2 line module and the GE-2 SFP I/O module
- GE-HDE line module and its associated I/O modules
- OC3/STM1 GE/FE line module and the OC3-2 GE APS I/O module
- ES2 4G LM and its associated Gigabit Ethernet and 10-Gigabit Ethernet IOAs
- ES2 10G LM and its associated Gigabit Ethernet and 10-Gigabit Ethernet IOAs

The maximum number of S-VLANs that you can create per I/O module with PPPoE major interfaces stacked over them is greater than the maximum number of dynamic PPPoE subinterfaces. The maximum number of PPP interfaces supported per line module is directly proportional to the maximum number of PPPoE subinterfaces.

As a result, you can oversubscribe S-VLANs by configuring up to the maximum number of S-VLANs supported on these I/O modules, knowing that no more than the maximum number of supported PPP sessions can be connected to the router at any one time.

For configuration instructions, see Configuring Dynamic PPPoE over Static PPPoE with Ethernet and S-VLAN Interface Columns in Configuring Dynamic Interfaces.

For specific information about the maximum number of S-VLANs supported per I/O module and the maximum number of PPP interfaces and PPPoE subinterfaces supported per line module, see JunosE Release Notes, Appendix A, System Maximums.

| Note: The E120 and E320 routers can support up to two IOAs per line module. This maximum number of S-VLANs per line module does not change if one or two IOAs are installed.