From: Hai Minh (minh@ipmac.com.vn)
Date: Mon Nov 08 2004 - 23:28:04 GMT-3
Ah, in my case, "ip igmp access-group" prevent host to join to multicast
group but the multicast group still goes through that interface, and "ip
multicast boundary" stop multicast groups at the interface.
Thank you, Scott, Tim and Bob.
Hai Minh
----- Original Message -----
From: "Scott Morris" <swm@emanon.com>
To: "'Hai Minh'" <minh@ipmac.com.vn>; "'ccie2be'" <ccie2be@nyc.rr.com>;
<ccielab@groupstudy.com>
Sent: Monday, November 08, 2004 10:44 PM
Subject: RE: Multicast question
> The multicast boundary is setting up a line that multicast groups either
> can, or cannot cross. Therefore, the multicast group is the important part
> there.
>
> HTH,
>
>
> Scott Morris, MCSE, CCDP, CCIE4 (R&S/ISP-Dial/Security/Service Provider)
> #4713, JNCIP, CCNA-WAN Switching, CCSP, Cable Communications Specialist,
IP
> Telephony Support Specialist, IP Telephony Design Specialist, CISSP
> CCSI #21903
> swm@emanon.com
>
>
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Hai
> Minh
> Sent: Monday, November 08, 2004 4:08 AM
> To: ccie2be; ccielab@groupstudy.com
> Subject: Re: Multicast question
>
> Tim,
>
> Yes, it's "ip igmp access-group" command.
>
> Thanks for your explaination, but I'm confuse why does the command "ip
> multicast boundary" consider the address as destination address.
>
> HTH
> Hai Minh
>
> ----- Original Message -----
> From: "ccie2be" <ccie2be@nyc.rr.com>
> To: "Hai Minh" <minh@ipmac.com.vn>; <ccielab@groupstudy.com>
> Sent: Monday, November 08, 2004 10:47 AM
> Subject: Re: Multicast question
>
>
> > Are you sure there is a command, ip multicast access-group. I looked
for
> it
> > but came up empty, however, there is a command, ip igmp access-group
which
> > is used to prevent joins.
> >
> > Now, this might be obvious to lots of people, but I didn't notice this
> until
> > it was explicitly pointed out to me, I think by Scott Morris.
> >
> > When the ip multicast boundary # command is used, it's referencing an
acl
> > just like the command, ip access-group #, so I wondered why was the ip
> > multcast boundary command needed. Isn't the ip access-group sufficient
to
> > do the job?
> >
> > The answer, of course, is it isn't. This is because when the ip
> > access-group # command is used, it interprets the ip addresses in the
acl
> as
> > source ip addresses. With the command, ip multicast boundary #, the ip
> > addresses referenced by the acl are interpreted as destination
addresses.
> >
> > A minor point, no doubt, but it highlights how important it is to pay
> > attention to details.
> >
> > HTH, Tim
> >
> >
> > ----- Original Message -----
> > From: "Hai Minh" <minh@ipmac.com.vn>
> > To: <ccielab@groupstudy.com>
> > Sent: Saturday, November 06, 2004 11:35 PM
> > Subject: Multicast question
> >
> >
> > > Hi group,
> > >
> > > I have this configuration. What is the different between the command
"ip
> > > multicast boundary" and "ip multicast access-group" in this case ? I
> think
> > > both of them are used to block the hosts to join to the multicast
group
> > > 226.26.26.26.
> > >
> > > Could someone please explain to me ?
> > >
> > > Thanks in advance
> > >
> > > ================
> > > R1
> > > interface E0/0
> > > ip multicast boundary 1
> > >
> > > interface E0/1
> > > ip multicast access-group 1
> > >
> > > access-list 1 deny 226.26.26.26
> > > access-list 1 permit any
> > > =======================
> > >
> > >
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