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Load Balancing 2 ISP connections on Cisco Router

Hi all,

I have a Cisco 3900 series Router with the following characteristics:

Cisco IOS Software, C3900 Software (C3900-UNIVERSALK9-M), Version 15.0(1)M2, RELEASE SOFTWARE (fc2)


I have two VDLS connections, my ISP cant really offer good speeds, so we have two connections of 3Mb/s each. (2x3Mbps).

Each link has its own modem and we get a /29 on each connection.


I have setup NAT on the router, but i am trying to use BOTH connections simultaneously. This is causing an issue for me. At the moment i am not able to use one of the connections for some reason.

I have re-created the very same scenario i have LIVE at the moment, in packet Tracer.

NOTE: uploading .pkt files is not allowed here, so i have uploaded it to

When trying to ping from one of the computers in the LAN ( to a Loopback address on Router 4 ( for example, i have 50% packet loss. I assume this is because one 50% of the packets are being routed via each connection.


Is there a practical way to solve this?


Please note that i am using the same NAT statements in both interfaces connected to the ISP, same ACL for the NAT statements as well.


Any advise is appreciated.



Everyone's tags (3)

An additional Note: The PKT

An additional Note: The PKT Lab was done with the Packet Tracer Student Version, not the normal packet tracer version. Anyone yet?

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