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No you are correct, they are both accomplishing the same thing. Whether you learn the MAC address through IGMP snooping or install it statically the switch is simply adding an entry into the CAM table for that destination mac-address:
Rack1SW1#sh run | include igmp|mac-address ip igmp snooping vlan 10 static 0100.5e01.0203 interface Fa0/16 mac-address-table static 0100.5e01.0204 vlan 10 interface FastEthernet0/16
Rack1SW1#show mac-address-table multicast Vlan Mac Address Type Ports —- ———– —- —– 10 0100.5e01.0204 USER Fa0/16 10 0100.5e01.0203 USER Fa0/16 16 0100.5e00.0128 IGMP Fa0/1, Fa0/6 22 0100.5e00.0128 IGMP Fa0/2
HTH,
Brian McGahan, CCIE #8593 bmcgahan@internetworkexpert.com
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> —–Original Message—– > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of > Paul Dardinski > Sent: Friday, June 30, 2006 3:49 PM > To: Cisco certification > Subject: RE: Multicast question > > So, using the static snooping entry would forward the traffic, but the > static mac table addressing wouldn’t? > > —–Original Message—– > From: David Timmons [mailto:masterdt@yahoo.com] > Sent: Friday, June 30, 2006 4:30 PM > To: Paul Dardinski; Cisco certification > Cc: yan.anchipolovskiy@prudential.com > Subject: RE: Multicast question > > Hi, > > If IGMP snooping is disabled, the switch will get the > multicast traffic. It will then lookup the MAC in its > cam table for a match. Now, without your cam entry, > the switch will flood the multicast out of every > interface except the one the traffic was received on. > So, without the entry, that interface and every other > interface would get the multicast traffic. So, I don’t > think the CAM solution is allowing the multicast > forwarding; however, it does help to minimize the > number ports that will get the traffic. > dt > — Paul Dardinski wrote: > > > Thanks David. > > > > The goal is to enable the multicast flooding out the > > port. Assume that > > ip igmp snooping is disabled on the vlan, would both > > cases would allow > > multicast packet forwarding? > > > > —–Original Message—– > > From: nobody@groupstudy.com > > [mailto:nobody@groupstudy.com] On Behalf Of > > David Timmons > > Sent: Friday, June 30, 2006 4:04 PM > > To: Cisco certification > > Subject: Re: Multicast question > > > > hmm, > > > > I think the IP IGMP snooping command is going to > > enable IGMP snooping and make your interface a > > member > > of the defined multicast group. When you create a > > static cam entry you just tell the switch where to > > forward the traffic; this will prevent the flooding > > out of all ports. So, I don’t think the CAM entry > > assisted with the sending of multicast traffic; > > although, it would reduce the broadcast traffic seen > > on the other ports of the switch. If the goal was to > > make an interface a member of a multicast group, I > > would think the cam method is a stretch. > > > > — Paul Dardinski wrote: > > > > > Rack1SW2(config)#mac address-table static > > > 0100.5e01.0203 vlan 10 int > > > f0/16 > > > > > > > > > > > > Rack1SW2(config)#ip igmp snooping vlan 10 static > > > 0100.5e01.0203 int > > > f0/16 > > > > > > > > > > > > > > > > > > Are these two statements equivalent? Assuming > > > ingress mcast traffic to > > > the vlan, will both forward traffic out f0/16? > > > > > > > > > > > > PD > > > > > > > > >