From: Joseph Brunner (joe@affirmedsystems.com)
Date: Tue Jul 08 2008 - 12:10:15 ART
right, but in my experience
"but i believe it only truly goes to dense-mode if an RP is
not known, right?"
it does this even in a network where every interface is SM only.
Try SM with just the multicast helper map feature making a feed run
constantly (yes remember to disable control-packets)
the see how the group looks with and without a known rp, oh, and make sure
you have a receiver down the line with
ip igmp join-group 224.x.y.z
-Joe
_____
From: Harindha Fernando [mailto:pottaharry@gmail.com]
Sent: Tuesday, July 08, 2008 10:45 AM
To: Learn Cisco
Cc: Joseph Brunner; John; ccielab@groupstudy.com
Subject: Re: Multicast Features
my understanding also same,
On Tue, Jul 8, 2008 at 5:29 PM, Learn Cisco <cisco.learn@yahoo.com> wrote:
i believe it reverts to a source-based tree after consulting the RP for each
multicast session, but i believe it only truly goes to dense-mode if an RP
is
not known, right?
----- Original Message ----
From: Harindha Fernando
<pottaharry@gmail.com>
To: Joseph Brunner <joe@affirmedsystems.com>
Cc: John
<jgarrison1@austin.rr.com>; Learn Cisco <cisco.learn@yahoo.com>;
ccielab@groupstudy.com
Sent: Tuesday, July 8, 2008 4:33:14 AM
Subject: Re:
Multicast Features
I checked on the lab
show ip multicast
will give u the
fallback mode
224.0.1.40 and 224.0.1.39 is for auto-rp rp announce and rp
discovery
(mapping agent), it will be in dense mode if you have configured IP
PIM
SM-DM but if you have only PIM SM configured on interface then you need ip
pim autorp listener to allow autorp packets to cross sparse mode interfaces.
On Tue, Jul 8, 2008 at 9:46 AM, Joseph Brunner <joe@affirmedsystems.com>
wrote:
> Where did you read that?
>
> even with all sparse-mode interfaces,
check 224.0..1.40 and any other group
> with no rp...
>
> -----Original
Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
Behalf Of
> Harindha Fernando
> Sent: Tuesday, July 08, 2008 2:39 AM
> To:
John
> Cc: Learn Cisco; ccielab@groupstudy.com
> Subject: Re: Multicast
Features
>
> Hi,
>
> If you have configured all the interfaces to PIM-SM then
fallback mode will
> be sparse , if you have at least one interface with
SM-DM then
> fallback mode will be Dense, by putting no ip pim
dm-fallback
> guaranties that fallback will be in Sparse mode.
>
> Rgds,
>
Harri
>
> On Tue, Jul 8, 2008 at 3:31 AM, John <jgarrison1@austin.rr.com>
wrote:
>
> > spt-threshhold is for source tree. The default is 0 kbs, which
means
> that
> > anything over 0 kbs will go to a source tree. no ip pim-dm
fallback is
> to
> > prevent, at least sparse-dense mode from falling back to
dense mode for
> > unknown groups. In the docs I've seen it used in sparse
mode and
> sometimes
> > not. I'm still trying to find a definitive answer on
that. Ill probably
> > end up labbing it on friday and then I'll know for
sure.
> >
> >
> >
> > "The mind is like a parachute it works best when it's
open"
> > ----- Original Message ----- From: "Learn Cisco"
<cisco.learn@yahoo.com>
> > To: <ccielab@groupstudy.com>
> > Cc:
<cisco.learn@yahoo.com>
> > Sent: Monday, July 07, 2008 5:27 PM
> > Subject:
Multicast Features
> >
> >
> >
> > hi, i'm trying to get a better grasp on
multicast topics. any feedback
> to
> >> the following questions would be
much appreciated:
> >>
> >> 1.) was wondering if anyone can help differentiate
between the use of
> "ip
> >> pim spt-threshold infinity" and "no ip pim
dm-fallback". they both seem
> to
> >> prevent sparse-dense-mode and/or
sparse-mode pim from reverting back to
> a
> >> sourced-tree / shortest-path
tree unless I'm missing something.
> >>
> >> 2.) would "ip pim accept-rp
auto-rp" be needed along with one of the
> cmds
> >> above to ensure no spt
paths form?
> >>
> >> 3..) when would "ip pim accept-rp x.x.x.x x" be used? i
guess if i get a
> >> question/requirement that states to have a device accept
join/prune
> messages
> >> for an rp i'd know to use this feature, but it
seems as though their
> might
> >> be more to this thing???
> >>
> >> 4.) "ip
pim autorp listener" is the feature to use when desiring to use
> >>
sparse-mode along with auto-rp, right? (without statically assigning
> the
>
rp
> >> mapping on all sparse-mode devices)
> >>
> >> thanks in advance for
any input,
> >>
> >>
> >>
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