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Secondary IP addressing

Is adding a second IP address to a router with only one ethernet interface the best solution when more IP addresses are needed on a LAN and the other subnet being used has had all the IP addresses exhausted? Will there be a performance issue if I add 12 more hosts from a different subnet on the same switch where there are 35 other hosts from another subnet within the same VLAN? I cannot use subinterfaces and ISL trunking since the ethernet interface is not a fastethernet interface.

Thanks,

RJ

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Accepted Solutions

Re: Secondary IP addressing

Since you dont have a fast ethernet interface, the only option you have is to use secondary ip addresses.

Adding 1 more subnet to the router ethernet interface as secondary shouldnt be a problem.

One thing to be noticed is that, the bandwidth of the link between the switch and the router will be shared with 12 more additional hosts, during communication between the 2 subnets. ( this case arises when all hosts are communicating simult., which is less likely).

Obviously there is a small percentage of load on the router, because it has to route more packets, not only to the wan, but also between the subnets.

3 REPLIES

Re: Secondary IP addressing

Since you dont have a fast ethernet interface, the only option you have is to use secondary ip addresses.

Adding 1 more subnet to the router ethernet interface as secondary shouldnt be a problem.

One thing to be noticed is that, the bandwidth of the link between the switch and the router will be shared with 12 more additional hosts, during communication between the 2 subnets. ( this case arises when all hosts are communicating simult., which is less likely).

Obviously there is a small percentage of load on the router, because it has to route more packets, not only to the wan, but also between the subnets.

Community Member

Re: Secondary IP addressing

Once again, thanks for your insight.

RJ

Community Member

Re: Secondary IP addressing

In some higher IOS version, you can configure the ethernet to trunk dot1q. I ever test the configuration, and it work well.

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