From: William Nellis (nellis_iv@yahoo.com)
Date: Thu Nov 08 2007 - 13:58:03 ART
food for thought, the client isn't listening to IP per se, the client will pick up from the wire anything sent to ffff.ffff.ffff, L2 broadcast address.
I am quite certain you do not need to explicitly configure broadcast address on the interface... its automagically configured as a result of the IP/subnet mask combination...
IE, if you don't explicitly configure it, it uses the deafult, which is the all 1's in the host portion of the subnet... Oh yes, the router knows it's broadcast address... the router knows all... mua ha ha ha
ip broadcast-address
To define a broadcast address for an interface, use the ip broadcast-address interface configuration command. To restore the default IP broadcast address, use the no form of this command.
ip broadcast-address [ip-address]
no ip broadcast-address [ip-address]
Syntax Description
ip-address (Optional) IP broadcast address for a network.
-------------------------------------------------------
r/s
William Nellis IV
nellis_iv@yahoo.com
----- Original Message ----
From: Joseph Brunner <joe@affirmedsystems.com>
To: Rich Collins <nilsi2002@gmail.com>; Anthony Sequeira <Anthony_Sequeira@skillsoft.com>
Cc: Cisco certification <ccielab@groupstudy.com>
Sent: Thursday, November 8, 2007 8:46:18 AM
Subject: RE: Errors in the DOC-CD for Multicast Intermediate Helper
No the client will listen to 255.255.255.255 also, it's a local broadcast.
That is just a caveat- the router realizes it's a directed broadcast, but
Sends by default to 255.255.255.255 instead of 126.1.28.255
-Joe
-----Original Message-----
From: Rich Collins [mailto:nilsi2002@gmail.com]
Sent: Thursday, November 08, 2007 10:19 AM
To: Anthony Sequeira
Cc: Joseph Brunner; Cisco certification
Subject: Re: Errors in the DOC-CD for Multicast Intermediate Helper
This has always confused me as well.
So on the final egress router in your example you would have this:
int S0/0
ip pim sparse-dense
ip multicast helper-map 239.254.2.5 126.1.28.255 105
int Fa0/0
ip add 126.128.1 255.255.255.0
ip directed-broadcast
ip broadcast-address 126.1.28.255
This is the best configuration to have the client of the application
pick up the UDP broadcast stream? I suppose this is better than the
default 255.255.255.255 broadcast which the client might not listen
to?
-Rich
On Nov 8, 2007 7:42 AM, Anthony Sequeira <Anthony_Sequeira@skillsoft.com>
wrote:
> Yeah - thanks Joe!
>
> This example used to be way off and had us placing commands on the wrong
> interfaces I believe.
>
> Anthony J. Sequeira
> #15626
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
>
> Joseph Brunner
> Sent: Wednesday, November 07, 2007 9:58 PM
> To: Anthony Sequeira; 'Cisco certification'
> Subject: RE: Errors in the DOC-CD for Multicast Intermediate Helper
>
> You mean the new documentation way in-line with current IOS where we
> place
>
> This
>
>
> ip multicast helper-map 239.254.2.5 126.1.28.255 105
>
>
> on the interface facing the multicast , not sending the final "back to
> lan
> broadcast" ?
>
> One cool thing-
>
> By default IOS sends "directed broadcasts" to 255.255.255.255 (even if
> the
> command above specified "126.1.28.255" as the broadcast to address). If
> you
> *really* want to send the broadcast to the subnet broadcast (directed)
> address you need to put ip broadcast-address 126.1.28.255 on the out
> going
> interface...
>
> Lab it up sometime, check it out...
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Anthony Sequeira
> Sent: Wednesday, November 07, 2007 9:19 PM
> To: Cisco certification
> Subject: Errors in the DOC-CD for Multicast Intermediate Helper
>
> Hello all!
>
>
>
> I am too tired right now to investigate so I am looking for immediate
> assistance from the group...it would appear that Cisco has finally
> corrected the Multicast Helper example in the DOC-CD.
>
>
>
> Can someone please confirm....
>
> http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cg/hi
> mc_c/chap10/mcbcigmp.htm#wp1084257
>
>
>
>
>
> Thanks in advance!
>
>
>
> Anthony J. Sequeira
>
> #15626
>
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