This is probably TCN based purging of snooping, and then it is being overly cautious.
there is a good bit of tuning you can do related to this though I'd start reading the documentation http://www.cisco.com/en/US/docs/switches/metro/me3600x_3800x/software/release/12.2_52_ey/configuration/guide/swigmp.html#wp999774 -Blake On Mon, Apr 8, 2013 at 5:50 PM, Jason Lixfeld <[email protected]> wrote: > Quick question about multicast flooding/blocking... > > I know that by default a switch will forward multicast on all ports in the > same broadcast domain. I think I've got it disabled with switchport block > multicast and igmp snooping enabled on the multicast vlan (4004) on the > 15.0(2)SE1 3560G-24TS I have running here. However, whenever I bounce a > port configured with vlan 4004 on it (trunk or access), I get a period of > 120 seconds where all ports in that VLAN are flooded with multicast traffic > from Gi0/24. After 120 seconds has elapsed, the multicast traffic from > Gi0/24 dies off and the flooding to any other connected vlan 4004 ports > subsides. > > There is an ME3600 connected to Gi0/24 and the multicast source is > connected to an access port on that ME3600 in VLAN 4004. The switchport > block multicast is configured there as well. > > It seems like I'm missing, or, have misconfigured a knob somewhere, but > I'm not quite sure what or where. > > Any insight? > > ! > interface range GigabitEthernet0/1 - 10 > description Facing Client > switchport trunk encapsulation dot1q > switchport trunk native vlan 4082 > switchport trunk allowed vlan 4004,4032,4082,4086 > switchport mode trunk > switchport block multicast > switchport block unicast > spanning-tree portfast > ! > interface GigabitEthernet0/24 > description Facing Multicast Source > switchport access vlan 4004 > switchport block multicast > switchport block unicast > ! > > Systems-Dev_Pit#sh ip igmp snooping vlan 4004 > Global IGMP Snooping configuration: > ------------------------------------------- > IGMP snooping : Enabled > IGMPv3 snooping (minimal) : Enabled > Report suppression : Enabled > TCN solicit query : Disabled > TCN flood query count : 2 > Robustness variable : 2 > Last member query count : 2 > Last member query interval : 1000 > > Vlan 4004: > -------- > IGMP snooping : Enabled > CAPWAP enabled : Disabled > IGMPv2 immediate leave : Disabled > Multicast router learning mode : pim-dvmrp > CGMP interoperability mode : IGMP_ONLY > Robustness variable : 2 > Last member query count : 2 > Last member query interval : 1000 > Systems-Dev_Pit# > > Thanks in advance. > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
