From: ccie2be (ccie2be@nyc.rr.com)
Date: Sun Nov 02 2003 - 15:25:24 GMT-3
See comments in-line.
----- Original Message -----
From: "Chen Kwong Wai William" <kwchen@netvigator.com>
To: "ccie2be" <ccie2be@nyc.rr.com>; "Group Study" <ccielab@groupstudy.com>
Sent: Sunday, November 02, 2003 12:18 PM
Subject: Re: PIM Multicast simple question
> Hi,
>
> Why when Multicast routing is enable on a router, by default, IGMP is
> enabled on LAN interfaces? I think we first need to confirm if it is true.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
This is documented in several places on the Doc-CD. Also, Willianson's book
and Doyle's book say the same thing.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>
> But, as in the DocCD, when you use "ip pim <dense-mode|sparse-mode|
> sparse-dense-mode>", the
> interface is also enable IGMP. Moreover, I can't find any command to
disable
> IGMP on an interface, so I think enable or disable PIM/IGMP are done on
the
> same time.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
That's not true. I believe IGMP can be disabled on an interface with a
command like
no ip igmp. I think the command ip igmp doesn't show up in the config file
because it's on by default when multicast is enabled. I just quickly looked
but didn't find the command. but, I'm fairly sure there's such a command or
a similar command that disables igmp. I'll keep looking.
>
> Please correct me if I am wrong, and anyone knows the detail here?
>
> Best Regards,
> William Chen
>
> ----- Original Message -----
> From: "ccie2be" <ccie2be@nyc.rr.com>
> To: "Group Study" <ccielab@groupstudy.com>
> Sent: Sunday, November 02, 2003 10:38 PM
> Subject: PIM Multicast simple question
>
>
> > Hi all,
> >
> > When Multicast is enabled on a router, by default, IGMP is enabled on
Lan
> > interfaces. That being the case, is it necessary to also enter the
> interface
> > command,
> >
> > ip pim <dense-mode|sparse-mode| sparse-dense-mode>,
> >
> > when there are only multicast hosts attached to that interface and no
> > possibility of other routers connecting to that interface?
> >
> > For example, if you have the following multicast network,
> >
> > R2------R1(E0)------switch------mcast hosts only
> >
> > does, ip pim <dense-mode|sparse-mode| sparse-dense-mode>
> >
> > need to be entered on the E0 interface of R1? Please explain why or why
> not.
> >
> > Thanks, dt
> >
> > _______________________________________________________________________
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