dell n2000 组播抑制

http://en.community.dell.com/support-forums/network-switches/f/866/t/19677497
http://en.community.dell.com/support-forums/network-switches/f/866/t/19650967
http://www.dell.com/Support/Article/us/en/04/SLN295739

# vlan20是组播vlan, 192.168.50.227接在Gi1/0/40接口
vlan 20
exit

interface vlan 20
ip address 192.168.50.227 255.255.255.0
exit 

interface range Gi1/0/25-40
switchport access vlan 20
exit

# 禁用默认、公网、内网vlan的igmp snoop 
no ip igmp snooping vlan 1
no ip igmp snooping vlan 10
no ip igmp snooping vlan 30

ip igmp snooping vlan 20 mrouter interface Gi1/0/40
ip igmp snooping querier
ip igmp snooping querier address 192.168.50.227
ip igmp snooping querier query-interval 120
ip igmp snooping querier timer expiry 300
ip igmp snooping querier vlan 20
ip igmp snooping querier vlan 20 address 192.168.50.227
ip igmp snooping querier election participate 20

没有开启客户端时，服务器接收不到upd流，开启客户端后，能够接到组播流，说明组播抑制生效。
tcpdump -i em2 -nn udp
tcpdump -i em2 igmp