Re: IP Multicast Helper Map Example - Wrong!!

From: Cisco Nuts (cisconuts@hotmail.com)
Date: Sun Nov 27 2005 - 23:31:42 GMT-3


On 11/27/05, Cisco Nuts <cisconuts@hotmail.com> wrote:

  Glad to!!

  If you look at this example in the Doc Cd:

  1. ip directed-broadcast is not needed on the first hop router,
  Router A e0 - you are just converting a broadcast to a multicast and
  thus this cmd. is not needed.

  2. The multicast helper map cmd. needs to be configured on Ethernet 1
  of the last hop router, Router C NOT on Ethernet 2 intf - because
  Ethernet 1 intf. is the receiving intf. of the last hop router and
  this is where the multicast packet needs to be converted back to
  broadcast.

  3. ip directed-broadcast cmd. on Ethernet2 intf. on the last hop
  router, Router C does make sense and it is correct - because ip
  directed-broadcast is off by default and to correctly forward te
  multicast packets to the receiving hosts, a subnet broadcast is
  required on the intf. connected to these hosts since we do not know
  which hosts in particular require the feed.

  Hope this helps.

  BTW: Lab 8 of InternetworkExpert explains this in detail.

  --------------------------------------------------------------------

  From: Niche <jackyliu419@gmail.com>
  To: Cisco Nuts <cisconuts@hotmail.com>
  Subject: Re: IP Multicast Helper Map Example - Wrong!!
  Date: Mon, 28 Nov 2005 09:09:47 +0800
>Hi there,
>
>Would you mind posting the configuration or the link here? I just
>wonder which part is wrong.
>
>Best Regards
>Jacky
>
>On 11/28/05, Cisco Nuts <cisconuts@hotmail.com> wrote:
> > Hello:
> >
> > Is there a way we can get Cisco to change the Multicast Helper
  map example
> > in the Doc CD?
> >
> > It is obviously wrong and can definitely lead one to "mis-learn"
  about this
> > feature.
> >
> > I have been seeing this for a couple of years now ;->
> >
> > Thanks !!!
> >
> >
  _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html



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