Question: what protocol is used for setting up the administrative tunnel in ipsec
[{'answer': 'Layer 2 Tunneling Protocol', 'provenance': [{'wikipedia_id': '350705', 'title': 'Layer 2 Tunneling Protocol', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 26, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '350705', 'title': 'Layer 2 Tunneling Protocol', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 338, 'bleu_score': 0.963949056609222, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4313586683367759318}, 'section': 'Section::::Abstract.'}]}]