RE: ip multicast helper-map - position of ip directed-broadcast

From: Scott Morris (swm@emanon.com)
Date: Sun Aug 14 2005 - 09:23:22 GMT-3

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Only the end-point router will need the "ip directed-broadcast" command.
Everyone else simply looks at it as a normal IP packet and forwards it on.
Only the last router makes the determination whether the address is actually
a subnet-broadcast or not. At any other point in the network, the routers
think there may be summarization or something going on, so it's not their
job to determine what is or is not a broadcast unless it's physically
hanging off that device.

HTH,

Scott

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Rajib Khan
Sent: Sunday, August 14, 2005 7:02 AM
To: Thomwin Chen; hin ccie; Brian McGahan; ccielab@groupstudy.com
Subject: RE: ip multicast helper-map - position of ip directed-broadcast
command ??

Thanks for your information Thomwin

So basically you don't even need "ip directed-broadcast" under source
ethernet interface which is R1 e0/0 of Hino's configuration right?

Thanks

Raj

Thomwin Chen <thomwin_chen@yahoo.com> wrote:
Rajib,

you will only need it on the final segment of the last hop router ( the
receiver's segment ).

this link is good to read :
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ics/cs006.htm

I tested it several weeks ago, and noticed the DocCD is incorrect.
btw, IE has similar task like this on Lab 8.

Rgds,
Thomwin

Rajib Khan <rajib56666@yahoo.com> wrote:
I think if you put ip directed-broadcast under s1/1 and e1/1 on R2 it should
still work.
Please correct me if I am wrong

Thanks

Raj

hin ccie wrote:
Thanks Brian,

I dont't have chance to lab it up. :(

I just wonder that the doc-cd could be incorrect.
Is somebody from Cisco aware about it ?

best regards
Hin

Brian McGahan wrote:
Yes, the documentation is incorrect. Try it out and you will see. You can
use the Service Assurance Agent (rtr) to generate a broadcast UDP for
testing it. This is also demonstrated in the IEWB-RS Volume I Solutions
Guide if you have access to it.

HTH,

Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com

Internetwork Expert, Inc.
http://www.InternetworkExpert.com
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________________________________________
From: hin ccie [mailto:hinccie@yahoo.com]
Sent: Saturday, August 13, 2005 2:12 AM
To: Brian McGahan; ccielab@groupstudy.com
Subject: RE: ip multicast helper-map - position of ip directed-broadcast
command ??

Thanks Brian,

I agree with you that it should be put on the bcast domain interface

Well, it is different according to

http://127.0.0.1:8089/cc/td/doc/product/software/ios122/122cgcr/fipr_c/ipcpt
3/1cfmulti.htm#wp1003511

that the ip directed-command is put on s1/1 R2

any thought ?
hin

Brian McGahan wrote:
Hino,

It need to go on E1/1 of R2. This is where the directed broadcast is being
sent to

HTH,

Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com

> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> hin ccie
> Sent: Friday, August 12, 2005 3:10 AM
> To: ccielab@groupstudy.com
> Subject: ip multicast helper-map - position of ip directed-broadcast
> command ??
>
> Guys,
>
> I'm rather confused about the position of ip directed-broadcast on the
> ip multicast helper-map configuration.
>
> I know that ip multicast helper-map config is put on the incoming
router
> interface
> of mcast traffic from source to receiver.
>
> Let's say
>
> source -- eth0/0 - R1 - s0/0 ---(mcast area) ---s1/1- R2- eth 1/1 ---
> receiver
>
> so it is broadcast -> mcast -> broadcast flow
>
> Where should I put the ip directed-broadcast command ?
> 1. on eth0/0- R1 (within broadcast area) 2. on s1/1 - R2 (within mcast
> domain - but it is the incoming
interface
> of mcast traffic) ??
> OR
> on eth 1/1 - R2 (within broadcast area) ??
>
> Please advise any help
>
> TIA
> hino
>
>
> ---------------------------------
> Start your day with Yahoo! - make it your home page
>
>

Next message: Gustavo Novais: "RE: distance command 2nd take - Correction to previous post"
Previous message: k_kaloianov@eircom.net: "Anybody going for the lab in Brussels on 04 October"
Maybe in reply to: hin ccie: "ip multicast helper-map - position of ip directed-broadcast"
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