Overlapping Error on Fast Ethernet Interface

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Jun 22nd, 2007
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Hi,


I have an AS5300 with 1 FA and Ethernet port. My subnet is 10.10.10.176/28, i assigned the 10.10.10.178 to FA port. but when i assigned any IP within those subnet, an error showed up saying overlaps with 10.10.10.176 on fast ethernet 0. I dont understand why it overlapps well in fact it is obvious that the ip is still on the same subnet. Any help or explanation on this..thanks

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Richard Burts Fri, 06/22/2007 - 09:18
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Rick


The IOS will not allow 2 LAN interfaces to operate at layer 3 and to have addresses within the same subnet. Either you must put an address in a different subnet on the second LAN interface or you must configure bridging on both interfaces, configure Integrated Routing and Bridging, configure an interface BVI and put the IP address on the BVI. If you really want to put both LAN interfaces into the same subnet it is possible. But as you can see it is complicated, and usually not worth it.


Perhaps you can explain to us why you want both LAN interfaces to be in the same subnet. What is the topology of the network and what connects to what interface?


HTH


Rick

del.rsharma Mon, 06/25/2007 - 20:35
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Hi Rick ,


Just want to confirm with you ,is each n every CISCO IOS nt allow 2 LAN interfaces to operate at layer 3 .or is it specificly related with AS5300 series router IOS .


awaiting reply?

Richard Burts Tue, 06/26/2007 - 04:40
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Rajesh


I am not clear about your phrase: "every CISCO IOS nt allow 2 LAN interfaces to operate at layer 3" and whether you really mean that or whether it is just an awkward phrasing (recognizing that for many English is challenging - and I do not put anyone down for awkward English). Certainly IOS does allow multiple LAN interfaces to operate at layer 3. But IOS does not allow 2 LAN interfaces on the same layer 3 device to operate with IP addresses in the same subnet. This is general with all IOS and is not specific to the AS5300.


HTH


Rick


del.rsharma Wed, 06/27/2007 - 06:52
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Thx to clarify that This is general with all IOS and is not specific to the AS5300,thats all i need to confirm

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