UTA培通用课程之一课程内容地址学习帧的转发/过滤回路防止交换机如何学习主机的位置交换机如何学习主机的位置交换机如何过滤帧主机D发送广播帧或多点帧广播帧或多点帧泛洪到除源端口外的所有端口冗余网络拓扑广播广播广播重复帧单点帧Unicast更复杂的拓扑结构可能导致多重回路在第2层没有能够防止这种回路的机制回路的解决办法:生成树协议Spanning-TreeProtocol基于软件实现每个桥只能有一个生成树每个桥通常最多到16个端口帧交换帧交换直通转发交换机检测到目标地址后即转发帧半双工(CSMA/CD)单向数据传送冲突可能性高用集线器连接全双工只能用于点对点连接到特定的端口两端均须支持全双工无冲突冲突检测电路关闭wg_sw_a(config)#ipdefault-gateway10.5.5.3wg_sw_a#showipIPaddress:10.5.5.11Subnetmask:255.255.255.0Defaultgateway:10.5.5.3ManagementVLAN:1Domainname:Nameserver1:0.0.0.0Nameserver2:0.0.0.0HTTPserver:EnabledHTTPport:80RIP:Enabledwg_sw_a#设置双工模式wg_sw_a(config-if)#duplexhalf双工不匹配管理MAC地址表wg_sw_a#shmac-address-tableNumberofpermanentaddresses:0Numberofrestrictedstaticaddresses:0Numberofdynamicaddresses:6AddressDestInterfaceTypeSourceInterfaceList-------------------------------------------------------------------------------------------------00E0.1E5D.AE2FEthernet0/2DynamicAll00D0.588F.B604FastEthernet0/26DynamicAll00E0.1E5D.AE2BFastEthernet0/26DynamicAll0090.273B.87A4FastEthernet0/26DynamicAll00D0.588F.B600FastEthernet0/26DynamicAll00D0.5892.38C4FastEthernet0/27DynamicAllwg_sw_a(config)#wg_sw_a(config)#wg_sw_a#shmac-address-tableNumberofpermanentaddresses:1Numberofrestrictedstaticaddresses:0Numberofdynamicaddresses:4AddressDestInterfaceTypeSourceInterfaceList--------------------------------------------------------------------------------------------------------------00E0.1E5D.AE2FEthernet0/2DynamicAll2222.2222.2222Ethernet0/3PermanentAll00D0.588F.B604FastEthernet0/26DynamicAll00E0.1E5D.AE2BFastEthernet0/26DynamicAll00D0.5892.38C4FastEthernet0/27DynamicAllwg_sw_a(config)#wg_sw_a(config)#mac-address-tablerestrictedstatic1111.1111.1111e0/4e0/1wg_sw_a#shmac-address-tableNumberofpermanentaddresses:1Numberofrestrictedstaticaddresses:1Numberofdynamicaddresses:4AddressDestInterfaceTypeSourceInterfaceList--------------------------------------------------------------------------------------------