RE: ip multicast helper-map - ip directed broadcast

From: Richard Dumoulin (richard.dumoulin@vanco.es)
Date: Mon Mar 15 2004 - 04:27:34 GMT-3


Ellie, I think you just need it wherever having to forward a directed
broadcast. In this case the directed broadcast is in the last interface of
the last hop router I suppose ?!?

--Richard

-----Mensaje original-----
De: Ellie Chou [mailto:ellie_chou@hotmail.com]
Enviado el: domingo, 14 de marzo de 2004 20:50
Para: kwchen@netvigator.com; braet_kamiel@nl.ibm.com;
ccielab@groupstudy.com
Asunto: Re: ip multicast helper-map - ip directed broadcast

I agree that "ip directed-broadcast" should be enabled on the outgoing
interface of the last hop. but how about the incoming interface of both
the first and the last hop? I see it configured on the example in the doc
CD but is it necessary?

The command guide says it's to "enable the translation of a directed
broadcast to physical broadcasts", and I think the only place that needs
it is the outgoing interface of the last hop. am I missing something
here?

thanks!

Ellie

>From: "William Chen" >Reply-To: "William Chen" >To: , >Subject: Re: ip
multicast helper-map - ip directed broadcast >Date: Thu, 4 Mar 2004
21:47:12 +0800 > >Hi, > > You are right. There is a mistake of this
example in DocCD. I have done a >lab in DoiT workbook from netmasterclass
(www.netmasterclass.com), which >gives a very good pratice of this
feature. > > Moreover, in order to generate UDP packets for testing
without any >traffic generator, you can use extended traceroute. > >Best
Regards, >William Chen > >----- Original Message ----- >From: >To: >Sent:
Thursday, March 04, 2004 5:29 PM >Subject: ip multicast helper-map - ip
directed broadcast > > > > Looking at the "ip multicast helper" example
on the Doc CD reachable via: > > > >
>http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fip
r_c/ipcpt3/1cfmulti.htm#1003511
> > > > I don't understand how the directed broadcast, created from the
multicast >stream at the incoming interface of the last hop router, is
sent out on the >outgoing interface as physical broadcast using default
interface >configuration. > > > > Because this interface will just drop
the directed broadcast arriving at >the interface. In order to prevent
this from happening the command "ip >directed broadcast should" be
configured on the outgoing interface of the >last hop router. > > > >
Since this example doesn't say anything about that, I'm still wondering
if >this is correct, could somebody confirm this? > > > >



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