Rick

May be stupid Q ...If PE-CE are directly cross connected this problem should not come up. Right?

thanks

shri

Shri

Whether the routers are cross connected or not has no bearing on this problem. If a static route points at an outbound interface (especially an LAN interface like Ethernet) then it needs to ARP for every destination address.

the reason for this is that to build the Ethernet framing to forward the packet it needs a destination MAC address. So for each destination it needs a MAC address and must ARP for each one. And cross connected or not has nothing to do with this.

If the next hop router does enable proxy arp then it works (I would say that it works poorly because of the extra work that the router must do - but it works). And if the next hop router does not support proxy arp then it does not work - regardless of cross connect.

HTH

Rick

They are cross connected CE----------PE

Here is explanation why you shouldn't do this

http://www.cisco.com/en/US/products/hw/routers/ps359/products_tech_note09186a00801c2af6.shtml#arp

Aleksey

Thanks for the interesting article. It makes the same point that I had made which is that a static route pointed to an Ethernet interface will cause the router to ARP for each destination address which is not reachable by a more specific route. But beyond the impact on router CPU (and the impact on router memory because the ARP table is likely to become VERY large) there is the risk that if the next hop router does not enable proxy arp then the ARP request will fail and the traffic will be dropped.

The solution is to use static routes with next hop addresses when the outbound interface is Ethernet.

HTH

Rick

Tanks everyone for the help...I now have a more crystal idea:)