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New Member


I have an interface that has a primary address of 10.x.x.x (private) and secondary address of 170.x.x.x (public). when a user on the 10 net is constantly accessing a sever that is addressed with 170 (same interface), when this cause a high utilization on the router? would it be quicker if we addressed the machine with a net 10 address? if so, why?

New Member

Re: Primary/secondary

Add "ip route-cache same-interface" to your interface config.


New Member

Re: Primary/secondary

From Cisco:

"If you enable fast or autonomous switching on an interface, packets coming from any other interface on the router are fast-switched (or autonomous-switched) to that interface. If you enable same-interface fast or autonomous switching, packets whose source and destination address are the same are fast or autonomous switched.

You might use same-interface fast or autonomous switching in cases where you have Frame Relay or Asynchronous Transfer Mode (ATM) WAN links configured as subinterfaces on the same main interface. Another situation is when you are using secondary networks on LAN interfaces, as during IP address migration. To enable same-interface fast switching, use the ip route-cache same-interface configuration command. "

Hope it helps


New Member

Re: Primary/secondary


If you have spare addresses on the 10.x.x.x network and you don't have any other restrictions you should change the server to that network. This way any packets from any host on the 10.x.x.x won't have to go to the router to reach the server. If hosts and server areon the same subnet, they wouldn't need to send packets to any gateway. The only thing they have to do is an ARP request to find the MAC address of the destination IP and the router isn't involved in this process.

Hope this helps.