Load Balance between 2 Cisco 3750 switches with equal-cost paths

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Jan 17th, 2012
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I have two offices in rural area with a quite distance between them. Offices are connected with private wireless 100Mbps and cooper 100Mbps links provided by different ISP. Wireless connections are delivered as a private L3 Ethernet link but cooper as private L2 Ethernet trunk link. In both offices I have Cisco 3750 L3 switches. I would like to use both link (equal-cost paths) in load balanced configuration but not sure how. Both switches running EIGRP. Asymmetric routing is not an option. Per-destination load-balancing or something else?

Any help is appreciate


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Joseph W. Doherty Tue, 01/17/2012 - 18:07
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Not quite sure how you avoid asymmetrical routing when load balancing.  Could you clarify this requirement?

wilson.jr Wed, 01/18/2012 - 08:12
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I'll be sending voice traffic via these links. Can somehow load balancing be symmetric or do I have any other solution to aggregate these two links?

Jeff Van Houten Tue, 01/17/2012 - 19:16
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could you route the copper Ethernet link? If so you could adjust the metrics to be equal cost at which point load balancing would be automatic.

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rizwanr74 Wed, 01/18/2012 - 08:54
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If on both link cost are equal (as per EIGRP resulted metric from both links) then EIGRP will do load-balancing by default.

However if both links cost are resulted in not equal metrics, then you can enable unequal cost load-balancing, please follow the Cisco documentation.


I assume this is how your offices are connected.

               |-------wireless------ |           __  

| Office A  |                          | Office B |

|               |______wired____|             |


Rizwan Rafeek

paolo bevilacqua Wed, 01/18/2012 - 09:38
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I don't think that 3750 switches can do unequal cost load balacing.

One would need a true router for that, an is not a good idea anyway.


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