最近监控的节目增加了，但是发现监控的质量明显下降，马赛克增多，收录效果也
不好。经查与交换机配置有关，增加了以下两条命令。
switchport block multicast 防止未知的多播报发送到本端口
switchport block unicast 防止未知的单播报发送到本端口
Switch#sh run
Building configuration...Current configuration : 6124 bytes
! version 12.2 no service pad service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname Switch ! ! no aaa new-model ip subnet-zero ! ip igmp snooping querier ! ! ! no file verify auto spanning-tree mode pvst spanning-tree extend system-id ! vlan internal allocation policy ascending ! interface GigabitEthernet0/1 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/2 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/3 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/4 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/5 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/6 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/7 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/8 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/9 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/10 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/11 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/12 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/13 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/14 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/15 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/16 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/17 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/18 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/19 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/20 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/21 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/22 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/23 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/24 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/25 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/26 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/27 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/28 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/29 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/30 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/31 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/32 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/33 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/34 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/35 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/36 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/37 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/38 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/39 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/40 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/41 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/42 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/43 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/44 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/45 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/46 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/47 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface GigabitEthernet0/48 switchport block multicast switchport block unicast spanning-tree portfast trunk ! interface Vlan1 ip address 192.168.0.254 255.255.255.0 no ip route-cache ! ip default-gateway 192.168.0.1 ip http server ! control-plane ! ! line con 0 line vty 0 4 password cisco login line vty 5 15 password cisco login ! end