Configuration steps

L2oGRE tunnels are emulated as an SDP of type gre-eth-bridged (shown as GRE-B in the output of relevant show commands). This SDP defines two end-points on the tunnel:

far-end IP address

This defines the IP address of the remote device that terminates the tunnel.
local IP address where the tunnel is terminated within an SR OS

This is a special IP address within an SR OS node that is not associated with any interface. It is only used for L2oGRE tunnel termination.

Binding an L2oGRE tunnel to an FPE-based PW port within the SR OS is performed through an Epipe service. When the connection is established, the tunnel payload can be extracted to a PW SAP that can be used similarly to a regular SAP under Layer 3 interfaces, subscriber interfaces, or an Epipe.

Table: L2oGRE tunnel example configuration describes the L2oGRE example configuration steps.

Table: L2oGRE tunnel example configuration
Step	Example CLI	Comments
PXC-based PW Port related configuration
PW Port creation	`pw-port 1` `encap-type dot1q` `dot1q-etype 0x8100`	L2oGRE tunnel is terminated on this PW port.
Port-XC creation	`port-xc` `pxc 1 create` `port 1/1/1`	This command triggers automatic creation of PXC sub-ports: `configure` `port pxc-1.a` `port pxc-1.b` This is where the L2oGRE terminating PW port is anchored.
Creation of FPE that is used for PW port anchoring	`fwd-path-ext` `sdp-id-range from 17400 to 17500` `fpe 1 create` `path pxc 1` `pw-port`	The application under this FPE is the PW port termination. The use of PW port in this case is versatile and can be used to terminate an L2oGRE or MPLS/GRE-based PW. In this example, it is used to terminate an L2oGRE tunnel.
L2oGRE tunnel definition
Configuration of GRE-bridged tunnel termination IPv4/IPv6 addresses.	`service>system>gre-eth-bridged` `tunnel-termination 10.1.1.2 fpe 1` `service>system>gre-eth-bridged` `tunnel-termination 2001:db8 ::1 fpe 1`	This is a special IPv4/IPv6 address that is not configured under any Layer 3 interface and it must not overlap with any IPv4/IPv6 address configured under an Layer 3 interface in Base router. Multiple termination IPv4/IPv6 addresses are supported.
Configuration of L2oGRE SDP	`service> sdp 2 gre-eth-bridged create` `far-end 10.1.1.2 local-end 10.1.1.2` or `service>` `sdp 2 gre-eth-bridged create` `far-end 2001:db8::2 local-end 2001:db8::1`	This represents the L2oGRE tunnel within SR OS as defined by the tunnel end-point IPv4/IPv6 addresses.
Stitching L2oGRE tunnel to an anchored PW port
Association between the PW port and a PXC port via FPE.	`service>epipe 1` `pw-port 1 fpe 1`	This command anchors the PW port 1 to a PXC port referenced in FPE 1.
Binding between L2oGRE tunnel and the PW port	`service>epipe 1` `pw-port 1 fpe 1` `spoke-sdp 2:1`	L2oGRE is terminated on a PW port and the Layer 2 payload within the tunnel is extracted on the PW SAP
PW SAP service association
Creation of services that use PW SAP	`service>epipe 100` `sap pw-1:100 create` `service>vprn 101>if` `sap pw-1:101 create`