ICMP router discovery protocol (IRDP) - help

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Jul 22nd, 2010
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Dear Friends,

As per my understanding, IRDP can be enabled on router interfaces, to send and receive Router Advertisements and Router Solicitations, enabling the hosts connected in the same subnet of the router interface to discover it's default gateway.

One of the command (optional) used under the router interface is 'ip irdp address address'. This command can be used twice under the router interface with preference to mention two different ip address. Could you please explain what exact address is to be used here in address fields.

Some documents says that it is the multicast address of the group to which router will send RA. Some other documents says that it is the ip address of the interface which will be used as the default gateway by the hosts.

The later explanation is seems to be logical, however, in some configurations, this address is that of a different subnet other than the particular router interface, which can not be used by the connected hosts as their default gateway.

Hope someone can help me out.


Ameen Ahmed.

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ameen.ahmed Fri, 07/23/2010 - 05:24
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Dear Friends,

Hope someone can help me..


Ameen Ahmed.

ameen.ahmed Fri, 07/23/2010 - 20:09
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Anyone there who could help me please...


Ameen Ahmed.

ahmed_eee_84 Thu, 08/12/2010 - 03:30
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Hello Ahmed;

The command ip address under the irdp configuration is used by the router to send proxy advertisments for another routers not running irdp to be used by segment hosts as default gateway.

Now the most common Scinario will be an IP address from the same Subnet as the hosts are.

but in the case of having the ip address outside your local subnet i think this will only work if you have proxy arp enabled on your interfaces and you have a route for this address in your RIB.


Ahmed Sameh


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