Unequal Load Balance with static routes

[nataliogatti]

I have a 1841 router attached to 2 ISP's. Each ISPs provides different bandwithd. I want to do load balance between them, but I want to do some sort of weighted load blance, so as to assign more traffic to one ISP than the other. A kind of 70/30 (70% of traffic via ISP1, and 30% of traffic via ISP2).

¿Is there a way to acomplish that? I already tried creating bogus /32 routes, but "cef" seems to be more clever and groups the bogus routes as one gw.

Thanks,

Natalio.

[cadet alain]

Hi,

take a look here:

http://blog.ioshints.info/2007/02/unequal-load-split-with-static-routes.html

Regards.

Alain.

[nataliogatti]

Thanks Cadet Alain, but I already tried that solution, with a different behaviour. It seems that in newer IOS's Cisco have made ip cef more clever and now it groups all routes associated to the same gw in one bucket.

Natalio.

[cadet alain]

hi,

then you can maybe try with PBR  if you haven't got delay sensitive or many udp traffic or you can try as above with cef disabled if it's ok for you to do per packet load balancing.

Regards.

Alain.

[nataliogatti]

Per packet load balance is not a choice for me. The ISPs provide different bandwithd and delay.

I didn't wanted to use PBR, but it seems the only way to go. I just wanted to do weighted load balance. It can be done very simple with a Linux router, so I thought that it could also be done in Cisco.

[cadet alain]

Hi,

PBR will also do per packet load balancing but you can use fast-switching for PBR not CEF.

Regards.

Alain.

[nataliogatti]

If there is no other solution, I will go with PBR.

I will have to do wat I didn't wanted to do: manually select wich IPs/Ports redirect to each ISP.

[Joseph W. Doherty · Accepted solution]

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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.

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Posting

Not sure if it's available on an 1841, but have you considered OER/PfR?

[nataliogatti]

Joseph:

It seems that OER/PfR was the functionality I was looking for. Why I never heard of it before? And in my extensive searches never found it

Thanks.

[cadet alain]

Hi Natalio,

if PfR is working for you would you be kind to explain how you set it up to achieve your goal because it would be interesting to see how it can solve your problem.

Regards.

Alain.

[Joseph W. Doherty]

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

Having used the technology, what it does is monitor actual load across the two links and inject routes for selected prefixes to bring the link loading into the proportions defined by their bandwidth statements.

Interestingly, you can start with static routing preferring just one path or both paths.  For a 70/30 split I would likely initially choose using both paths.  I had a site with a fractional (half) DS3 and a DS1.  For that, I started with all traffic directed to the DS3.

Unlikely other forms of variable bandwidth routing, whether static or EIGRP, OER/PfR isn't static it's dynamic.

[cadet alain]

Hi Joseph,

I knew the product only theoretically via the written curriculum and basic config but I didn't know how you could achieve unequal load with it via delay/ packet drops.So it was more the implementation that was interesting me.

Regards.

Alain.

[Joseph W. Doherty]

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

Alain, I understand.

A reason I responded, I suspect Natalio may have only had read about the technology and not have a working implementation.

I would post for you an actual working configuration from my experience using the product, but I'm working for someone else who doesn't use this technology.  Unfortunately, don't have a copy of any of the configs I used to use.

I recall a configuration to support just basic load balancing is about as simple as it gets.  The only parameters I thought worth changing from their defaults was the time computation parameters, i.e. how often it OER/PfR reviews what's happening and how long a time period it analyzes.  I vaguely recall for load analysis OER/PfR would also use interface load-interval settings, but I'm not positive on that.