Question: which are the port roles in stp protocol
[{'answer': 'root', 'provenance': [{'wikipedia_id': '98761', 'title': 'Spanning Tree Protocol', 'start_paragraph_id': 7, 'start_character': 510, 'end_paragraph_id': 7, 'end_character': 514, 'bleu_score': 1.0, 'section': 'Section::::Protocol operation.\n'}]}, {'answer': 'designated', 'provenance': [{'wikipedia_id': '98761', 'title': 'Spanning Tree Protocol', 'start_paragraph_id': 34, 'start_character': 18, 'end_paragraph_id': 34, 'end_character': 28, 'bleu_score': 1.0, 'section': 'Section::::Configuring a spanning tree.:Protocol choice of the path to the root bridge.:Breaking ties in selecting the path to the root bridge.\n'}]}, {'answer': 'blocked', 'provenance': [{'wikipedia_id': '98761', 'title': 'Spanning Tree Protocol', 'start_paragraph_id': 35, 'start_character': 710, 'end_paragraph_id': 35, 'end_character': 717, 'bleu_score': 1.0, 'section': 'Section::::Configuring a spanning tree.:Protocol choice of the path to the root bridge.:Breaking ties in selecting the path to the root bridge.\n'}]}, {'provenance': [{'wikipedia_id': '98761', 'title': 'Spanning Tree Protocol', 'start_paragraph_id': 38, 'start_character': 0, 'end_paragraph_id': 38, 'end_character': 503, 'bleu_score': 0.9757530668325981, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1527381640742872462}, 'section': 'Section::::Bridge Protocol Data Units.\n'}]}]