Isolated Networks

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Jul 15th, 2008
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I have a network, OSPF is the protocol, now i want to add one more network in it, but both the networks should be separte from each other, there is no more availabe physical iterfaces are on my devices. Can i meet my requirement..??

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shijomon scaria Tue, 07/15/2008 - 20:45
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here i am attaching the diagaram, where the 157.x.x.x network is communicating each other perfectly using OSPF. Now i want to add one more network, belongs under 156.x.x.x range to this topology, my requirement is both the networks (157.x.x.x and 156.x.x.x) shold not communicate each other, same time, subnets belongs 157.x.x.x and 156.x.x.x on different locations should communicate each other. But remember one thing that there is no more availble physical interfaces on my routers, also the switches are non-mangeble ones. Can i have a solution with the current topology, otherwise how can i alter my topology to meet my requirement?

Thank You

Giuseppe Larosa Wed, 07/16/2008 - 02:04
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Hello Shijomon,

on LAN interfaces you can use :

different subifs for different vlans


secondary ip addresses

on wan interface stay with the 157.x.x.x addresses only

Be aware that OSPF work only on primary addresses but it is classless so you don't need to worry about partitioned major networks. You can advertise the secondary subnets with the usual network command but no adjaciencies are built using secondary addresses.

To complete the solution you will need to configure ingress ACL on lan interfaces where you will decide what communication is possible.

Hope to help



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