OSPF routing question

[Peter Kim]

I currently have two 10 Gig circuits between two data centers running OSPF.  So, it is doing load balancing.  I just installed a new 100 Gig circuit between two data centers.  I know I have to adjust auto cost reference to get 100 Gig circuit to be prefer route.  Is there way I can manually distribute traffic between 100 Gig and 10 Gig.  For example, I'd like to put 70% of traffic on 100 Gig and 30% on 10 Gig or something like that. 

Any suggestion will be appreciated.  

[Richard Burts]

If you want to exert manual control (and the associated manual effort to implement, to monitor, and to fine tune) then I would suggest that you look into Policy Based Routing. You would make the necessary changes in reference bandwidth so that it can distinguish the 100 Gig circuit. This would direct all traffic to the 100 Gig circuit. Then you would use PBR to identify some traffic that would be about 30% of the traffic and direct that over the other interfaces.

HTH

Rick

[Peter Kim]

Thanks for your reply Rick.  I will look into PBR.

[Julio E. Moisa]

Hi,

It is just an idea, but I think you could use MQC in order to apply traffic shaping like shape or police. This way will allow you to assign percent of traffic for this links and matched to any kind of traffic.

it could be useful: http://packetlife.net/blog/2008/jul/30/policing-versus-shaping/

[Joseph W. Doherty]

Policing or shaping might be used to insure some traffic doesn't use more than a certain amount of bandwidth, as for example, if you didn't want FTP to use more then 2g on the 10g link or more than 7g on the 100g link, but it (alone) wouldn't split FTP flows across both links by some ratio.

I recall PfR can tie into MQC traffic classes, so it might be able to split different classes across different paths in ratios you set.  I'm not sure, though.  I know the original/earlier OER could not.

By default, OER/PfR would split traffic based on link capacities, so for 10g and 100g, it would try to load both at an equal percentage.  However, I also recall OER/PfR had tier costing, which could influence how it managed link bandwidths.  I.e. as in OP, if you wanted 3:7 ratio vs. 1:10, it might be able to support that.  Again, I'm not sure.  When I used it, my goal was to load links to the same load percentage.  For that, it worked great.  (NB: due to a circuit mis-order I had a case where one link was a T3 and the other a T1.  With OER/PfR, both were actively used, and flows directed to each to keep both at about the same load percentage.)

[Peter Kim]

I really appreciate your input.  I will have to investigate on this subject before I implement.  Thanks again.

[Reza Sharifi]

Have never deploy it but if your routers/IOS support it, you may want to look at PFR as OSPF does not support unequal cost path load balancing. Or just use the 100Gig as primary and the 10Gig as backup.

http://docwiki.cisco.com/wiki/Performance_Routing_FAQs#Q._What_is_Cisco.C2.AE_Performance_Routing.3F

HTH

[Joseph W. Doherty]

When you're dealing with a 10:1 bandwidth ratio, any static load balancing, such as PBR suggested by Rick, or something like EIGRP's unequal cost, is usually not worth the effort, as the lessor bandwidth path might congest while there's ample bandwidth on the higher bandwidth path.  (Also as Rick noted, PBR generally needs much manual effort.)

Reza's suggestion about PFR might be ideal, as it does dynamic load balancing, but as he also noted, your equipment (and its licensing) needs to support it.  Good chance your DC devices, using 10g and 100g links, does not.  BTW, I've used OER/PfR, and when I used it, it worked very nicely.