bundle three interface with different bandwidth on router

[Zhixin]

7606 has three ISP links,and these both connect to GigabitEthernet. The bandwidth is 2M,2M,10M。I want to bundle these interfaces .I want to know if Port-channel can achieve this and How to control the load-blance?

[Sergey Lisitsin]

Zhixin, 

You can put interfaces into EtherChannel, but with an uneven number of interfaces and with uneven bandwidths it is not recommended. You will end up with a highly unbalanced load distribution across your links. Also, if these links go to different devices, this is not possible. You will be much better off using layer 3 load sharing, for example running EIGRP on these links if possible. 

[Georg Pauwen]

Hello,

you can install multiple default routes and achieve unequal cost load balancing with this. You 'trick' your router into thinking there are different default routes to the same destination. In your case, you need a 1:1:5 ratio (2MB/2MB/10MB).

Have a look at the configuration below:

Let's say the below are the IP addresses of your ISPs:

ISP 1: 100.100.100.1
ISP 2: 150.150.150.1
ISP 3: 200.200.200.1

Create seven default routes with IP address that are not in use:

ip route 0.0.0.0 0.0.0.0 10.10.10.1
ip route 0.0.0.0 0.0.0.0 10.10.10.2
ip route 0.0.0.0 0.0.0.0 10.10.10.3
ip route 0.0.0.0 0.0.0.0 10.10.10.4
ip route 0.0.0.0 0.0.0.0 10.10.10.5
ip route 0.0.0.0 0.0.0.0 10.10.10.6
ip route 0.0.0.0 0.0.0.0 10.10.10.7

Now create 7 static routes using the unused IP addresses, and point them to your ISPs in ratio:

ip route 10.10.10.1 255.255.255.255 100.100.100.1
ip route 10.10.10.2 255.255.255.255 150.150.150.1
ip route 10.10.10.3 255.255.255.255 200.200.200.1
ip route 10.10.10.4 255.255.255.255 200.200.200.1
ip route 10.10.10.5 255.255.255.255 200.200.200.1
ip route 10.10.10.6 255.255.255.255 200.200.200.1
ip route 10.10.10.7 255.255.255.255 200.200.200.1

The router does per-destination load balancing by default.

[paul driver]

Hello

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@Georg Pauwen wrote:

you can install multiple default routes and achieve unequal cost load balancing with this. You 'trick' your router into thinking there are different default routes to the same destination. In your case, you need a 1:1:5 ratio (2MB/2MB/10MB).

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The problem with this is you most probably get the same results for the users as the reason being say the most used application is being serviced over just the one link leaving the other links under / over -utilised, Also I am not sure how the liegitmate traffic will still be routed with these phoney statics?.

I would suggest to look at a load balancer-wan aggregation device - You get some some decent branch ones nowadays that can bond multiple wan links and split a traffic flow over multiple links that will inherintly increase the end users wan connection with really hardly or any configuration changes to you exiting router These devices just sit in between your router/Fw and the isp and does it stuff

[jmperlewitz]

I agree with using the WAN Aggregator device. If you are using NAT, that is an extra complexity you have to account for since you will have to use policy-based NAT.

[Zhixin]

It's fantastic! I don't understand. Why use unused IP address instead of ISP address?
thanks.

[a.alekseev]

sh ip cef 0.0.0.0/0 internal