＝OSI Model and Transmission Path＝ 　A．OSI 7-Layer Model 　B．Signals and Network Media 　C．Data Link Layer 　D．Bridges and Repeaters 　E．ARP and ARP tables 　F．Topologies and Access Methods 　 Related Items 　F-1　Topologies 　F-2　Access Control Methods 　F-3　appendix The types of LAN 　　・　Exercise