[Openais] Why to avoid 224.x.x.x series of IP address for multicast

[Steven Dake]

On Wed, 2008-08-13 at 05:39 +0000, Hegde, Ramesh (OpenCall) wrote:
> Hello ,
> 
>  
> 
> In the man page description regarding multicast address I find that,
> 
> “This is the multicast address used by openais executive. The default
> should work for most networks, but the network administrator should be
> queried about a multicast address to use. Avoid 224.x.x.x because this
> is a "config" multicast address "
> 
>  
> 
> Could you please elaborate on the following sentence 'Avoid 224.x.x.x
> because this is a "config" multicast address'?
> 
>  
> 
> My understanding is that the 224.0.0.0 to 224.0.0.255 range is
> assigned for multicasting on the local LAN only.  If it because all
> these addresses are already reserved ? I see some details on this in
> the following link
> 
> http://www.iana.org/assignments/multicast-addresses
> 
>  
> 
> Let me know the details.
> 

224.x.x.x works like a broadcast.  It will be sent to every machine in
the network connected to the lan.  Usually you will just want to send to
a specific subgroup of machines that are actually in the cluster.

Also 224.0.0.x is used for config addresses as shown by iana and should
not be used by applications.

For example ping 224.0.0.1 and see what happens :)


> 
> Regards
> 
> Ramesh
> 
>  
> 
>  
> 
> Ramesh Hegde 
> 
> Software Engineer, Hewlett Packard
> 
> 
> India Software Operations Pvt. Ltd 
> 
> 
> Sy No 192, Whitefield Road
> 
> 
> Mahadevapura Post
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> 
> Bangalore - 560 048. India. 
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> 
> +91 80 2516 6486- Direct 
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> +91 80 2513 3522 - Fax 
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> 
> Jabber Id : rameshh at jabber.hp.com 
> 
> 
> +hp = everything is possible
> 
>  
> 
>