Question

How can I accomplish load balancing with redundancy?

Load balancing, Networking, Routing, Redundancy, OER, ISPs, Cisco routers, configuration, Natting, Access Control Lists

I have two links with different ISP's and both the (512Kbps) links are terminated on separate Cisco routers (2811). Currently, we are using one link. Another link is new. I want to do load sharing and redundancy between them. Right now I am not using BGP (routers are configured in simple manner). My client and I are concerned with cost.

My present network scenario looks like this:
Internet Ri (ISP 1) -- Layer 3 switch (working here as a simple switch) --- Firewall 1 (Cisco ASA5510) -- Firewall 2 (Cisco ASA5510) --- LAN.

On Firewall 1, remote and site-to-site VPN is configured -- one DMZ. My LAN is in the 172.16.1.xx series; my DMZ is in 172.16.4.10, and after 172.16.1.30 is used for the desktop, 192.168.x.x is the management IP.

Right now I have one other Internet link (512kbps) from a different ISP. So please tell me how I can accomplish load balancing with redundancy.

I've tried OER but unsuccessfully, due to IOS image (c2800nm-ipbasek9-mz.124-11.T.bin) and ISP's AS. Can it be possible through natting, and ACL? Please help me with the OER or anything I've mentioned. If possible, please show me a sample configuration.

It's a little tricky. Which direction do you want to do load-balancing? For incoming traffic to your network either you need to do BGP with your ISPs or you need to have a link load balancer kind of a box which has intelligence to understand the load on each link. You might need an AS number from the ISP. As far as the load balancing of outbound traffic from your network is concerned, you need to have a firewall with a load-balancing capability on which both the links are terminated through routers.

You can find sample configurations from networking sites on the Internet. You can also try Cisco.com.

Hope this helps.