OSI model
OSI参照モデル
https://courses.edx.org/assets/courseware/v1/5f0aa5aa259af95f0e95d5a8c51877d5/asset-v1:WGUx+ITEC2102+3T2019+type@asset+block/ITEC2102_U2_S1_P3_Image1.pngNetwork and Security Foundations - edX
https://i.imgur.com/Tqa2Dbx.jpghttps://imgur.com/Tqa2Dbx?r