https://www.cisco.com/c/en/us/td/docs/ios/solutions_docs/vpdn/L2TP_case_study/l2tpsol/l2tp_syn.html
Access VPDN Dial-in Using L2TP - Synopsis of Access VPDN Dial-In Using L2TP [IP Tunneling] - Cisco
dial inip tunnelingaccessvpdnusing
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-auto-mlt-tun.html
IP Multicast: PIM Configuration Guide - Automatic Multicast Tunneling [Cisco ASR 1000 Series...
IP Multicast: PIM Configuration Guide - Automatic Multicast Tunneling
cisco asr 1000ip multicastconfiguration guidepim