Load Balancing on Cisco 1811

[someone6162]

I'd like to set my network up in the following way:

ISP#1: Cable @ 6Mbps
ISP#2: DSL @ 3Mbps
Router: Cisco 1811 (with dual WAN FE ports)

I'd like to connect both ISP connections to my one router. I'd then like the router to load balance these connections and share the internet to my clients using NAT. I'd like for the router to detect if a connection goes down and automatically transfer bandwidth to the working ISP, then redistribute bandwidth once the downed ISP comes back up. My clients on the internal network use 192.168.234.x. The two ISP's use different DNS servers. They prevent access to their DNS servers for requests originating from other ISP's. So, what is the best way to handle this situation? I can't simply send out DNS packets through random ISP's because if it goes to the wrong ISP's DNS server, the request will get blocked (timed-out).

I'm still quite new with Cisco routers, so if someone could give me a step-by-step procedure for doing the above (through the CLI), I would very greatly appreciate it.

Thanks

 

[KiscoKid]

Before you get into specific configurations, can you explain what options you have regarding routing protocols available from your ISPs, i.e. do they support BGP, static, OSPF etc. BGP is arguably the best way forward here, you may need to ask them what they support.

Let me know.

 

[someone6162]

Hi KiscoKid,

Thanks for your reply. I contact both ISPs, and they told me they both support BGP. They told me BGP operates on UDP port 179, and that they do not block that port. I hope that helps.

Thanks

 

[someone6162]

After doing a bit more digging, I've realized that my ISP's do not support BGP. They are standard cable and DSL connections.

Can anyone help me solve this design issue please??

 

[someone6162]

Does anyone have any suggestions??

 

[KiscoKid]

If they dont' support BGP that limits you somewhat. I admit I'm shocked that an ISP is offering a feed to customers without a BGP offering. As you're quite keen to implement resilience in your design, I would probably recommend 'Reliable Static Routing' as a solution. This will detect failures and simply flip over to the other ISP in the event it loses an ICMP probe.

Take a look at the following URL and see what you think:

http://www.cisco.com/en/US/products/sw/iosswrel/ps5413/products_feature_guide09186a00801d862d.html