Redundant link configuration

[eandrcisco007]

Gentlemen,

I have two switches that are connected to L3 MPLS with the same AS,

They both in active /active state replicating traffic to another site ,  the first switch is our primary link with 200 mbps and the 2nd one works as a backup with redundant link that has 50 mbps,

We would like to forward some traffic to our redundant link (2nd switch with 50 mbps) when the primary switch is overloaded upon replicating, 

Any ideas or suggestion as to what options do i have in order to try?

Thank you in advance.

Regards

[syed kazim abbas]

Can you provide the configuration of both switches and draw a roughly diagram to understand better for better solution.

regards,

kazim

[eandrcisco007]

Thank you Kazim, I am unable to share the configuration but i am suspicous about the configuration of qos on the primary switch that could possibly be incomplete and i was wondering if any one have done something like that or any suggestion to be able to get some guiedence or sample configuration.

Please let me know.

[Joseph W. Doherty]

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Posting

OER/PfR might be an ideal solution, as they both do dynamic load balancing, but it's not supported on most L3 switches.

[eandrcisco007]

thank you Joseph for your input, i am going to check and verify the possibility but in the meantime, do you think implementing a policy map qos .... would do the trick?

[Joseph W. Doherty · Accepted solution]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

No, not for moving usage between links.  Only something like OER/PfR does it dynamically.  EIGRP can proportionally share link bandwidth, but its not dynamic.

Where QoS can aid, is how you manage congestion.  I.e. when there's congestion, you can guarantee necessary bandwidth for some traffic (but taking bandwidth from less important traffic).

[rothomas2]

Saying no its maybe a too soon answer. We would have to understand your routing. And also where your traffic is coming from. 

Also is your upload/download traffic that you want to balance. You can always advertise more specific routes to 'drag' some traffic via your other link, or change your outbound routes to 'push' some traffic through your other link. 

I do agree there's nothing QoS can do to balance amount of traffic. 

But you can certantly do this with routing, and some static routes. In the end what PfR does is inject routes and play with BGP attributes to have this effect, of having some 'flows' over a specific interface. 

How can you learn more about your flows? Easy, roll out Netflow over your network and you can see how to split flows. 

[eandrcisco007]

i totally understand your point and .... thank you rothomas2!

its all about upload and where replication happen between sites so the primary switch gets banged up and we want some of this traffic to bounce on the other link that is currently idling and to take some pressure off primary link, FYI we are using bgp and eigrp,

Can you provide some more details or possibly a sample configuration or some example as to how to advertise some specific routes via other link particularly....without using PfR? are you talking about redistribution or ...? How can we change our outbound route and push it through the other link?