Hi,
Between CSR and CSR2 there is standard ip connectivity.
In the next example I attached the only reason i set OSPF is for route traffic between 1.1.1.1 and 2.2.2.2.
The relevant configuration is:
CSR#
l2tp-class class1
authentication
password secret
pseudowire-class vlan-xconnect
encapsulation l2tpv3
protocol l2tpv3 class1
ip local interface Loopback0
interface gi1
xconnect 2.2.2.2 123 pw-class vlan-xconnect
CSR2#
l2tp-class class1
authentication
password secret
pseudowire-class vlan-xconnect
encapsulation l2tpv3
protocol l2tpv3 class1
ip local interface Loopback0
interface gi1
xconnect 1.1.1.1 123 pw-class vlan-xconnect
Also attach a document for your reference:
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/wan_lserv/configuration/15-mt/wan-lserv-15-mt-book/wan-l2-tun-pro-v3.html#GUID-499FB5ED-55F2-4F68-8767-0582E424684E
