# L2TP Module Requirements

The supported modules for LNS depends on the type of E Series router that you have.

## ERX7xx Models, ERX14xx Models, and the ERX310 Router

To use an LNS on ERX7xx models, ERX14xx models, and the ERX310 router, at least one Service line module (SM) or a module that supports the use of shared tunnel-server ports must be installed in the ERX router. For information about installing modules in the ERX router, see the ERX Hardware Guide.

SMs provide dedicated tunnel-server ports that are always configured on the module. Unlike other line modules, SMs do not pair with corresponding I/O modules that contain ingress and egress ports. Instead, they receive data from and transmit data to other line modules with access to ingress and egress ports on their own associated I/O modules.

You can also create tunnels on E Series modules that support shared tunnel-server ports. You can configure (provision) a shared tunnel-server port to use a portion of the module’s bandwidth to provide tunnel services. For a list of the modules that support shared tunnel-server ports, see the ERX Module Guide.

For information about configuring tunnel services on dedicated and shared tunnel-server ports, see the Managing Tunnel-Service and IPSec-Service Interfaces chapter in JunosE Physical Layer Configuration Guide.

For information about line modules supported by the LAC and LNS and the type of support each module type receives, see ERX Module Guide, Appendix A, Module Protocol Support.

## E120 Router and E320 Router

To use an LNS on an E120 router or an E320 router, you must install an ES2 4G line module (LM) or an ES2 10G ADV LM with an ES2-S1 Service I/O adapter (IOA), or an IOA that supports the use of shared tunnel-server ports. For information about installing modules in these routers, see the E120 and E320 Hardware Guide.

The combination of an ES2 4G LM or an ES2 10G ADV LM with an ES2-S1 Service IOA provides a dedicated tunnel-server port that is always configured on the IOA. Unlike SMs, the ES2 4G LM and the ES2 require the ES2-S1 Service IOA to condition it to receive and transmit data to other line modules. The ES2-S1 Service IOA also does not have ingress or egress ports.

You can also create tunnels on IOAs that support shared tunnel-server ports. You can configure (provision) a shared tunnel-server port to use a portion of the bandwidth of the IOA to provide tunnel services. For a list of the IOAs that support shared tunnel-server ports, see the E120 and E320 Module Guide.

For information about IOAs that are supported by the LAC and LNS and the type of support each module type receives, see E120 and E320 Module Guide, Appendix A, IOA Protocol Support.