From: shiran guez (shiranp3@gmail.com)
Date: Wed Oct 31 2007 - 10:17:58 ART
I think in real world that if your already configuring each router with
static RP for him self why not configure to the real RP and do not use
AutoRP as AutoRP is nice but if you want to be sure static is the best
solution.
in real big networks I do not think that any one will configure static RP to
him self on all the routers and additionally add AutoRP, it look like more a
bad design idea to do that.
I would appreciate to get also more opinions on that, as I think this issue
is very interesting in today growing IPTV networks that use Multicast in a
very large scale.
like verizon / pccw / france telecom and others
On 10/31/07, Con Spathas <con@spathas.net> wrote:
>
> To be honest I haven't really tested it either - however I could see it
> used
> in an environment as follows:
>
> DM used for selected groups and then SM for all other groups (ip pim
> sparse-dense mode).
> Then should there be a failure with any of the RPs, Auto-RP or BSR
> responsible for the SM traffic - this traffic then won't be able to drop
> back into DM and ruin your networks day.
>
> I am of the same opinion at the minute as you are that this command
> appears
> to be redundant in a purely SM environment aside from perhaps serving as a
> peace-of-mind safety net.
>
> From what I've read this command came about from an old workaround whereby
> each router would have the RP statically configured pointing itself just
> in
> case there was an AutoRP failure.
>
> I'd be interesting in reading others comments as well.
>
> Cheers!
>
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> nicky noname
> Sent: Wednesday, 31 October 2007 11:00
> To: Cisco certification
> Subject: no ip pim dm-fallback
>
> Hello!
>
> I have come across this alot in the documentation ( also on the sample
> configs with sparse-mode) and it seems to stress that you must configure
> this command to prevent multicast groups from defaulting to dense
> mode........regardless of interface configuration and in absense of RP.
>
> Now, this is implying that if I configure "ip pim sparse mode" in the
> interface and I DO NOT have "no ip pim dm-fallback" configured.......that
> if
> someone tries to multicast for an particular group that is undefined by an
> RP, it will revert to dense mode on the network.
>
> I don't believe this but!!.....I will test today!
>
> some experienced comments...have you tested this. If it is the case, then
> you must always put this command in when you want no dense
> mode..........even if you have sparse only configured!.....doesn't seem
> right thanks Nic
>
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-- Shiran Guez MCSE CCNP NCE1 http://cciep3.blogspot.com http://www.linkedin.com/in/cciep3
This archive was generated by hypermail 2.1.4 : Fri Nov 16 2007 - 13:11:19 ART