Layer 2 Tunneling Protocol version 3 (L2TPv3) is a mechanism for the tunneling of Ethernet traffic over an IP network. For this application, the ISA functions as a resource module for the system, performing the L2TPv3 encapsulation and decapsulation functions.
Figure: L2TPv3 support for IP transport shows L2TPv3 support for the IP transport model. Table: L2TPv3 support for IP transport — tunnel processing steps describes the tunnel processing steps in the figure.
| Step number | Description |
|---|---|
1 |
The L2TPv3 control plane can run within either the base routing or VPRN contexts. |
2 |
L2TPv3 encapsulated packets ingress and egress through the public interface, which can be in either the base routing or VPRN contexts. |
3 |
L2TPv3 encapsulation and decapsulation processing is handled within the tunnel ISA. |
4 |
Unencapsulated packets pass between the tunnel ISA and the associated service via the configured private SAP. |