OSPF unequal cost load sharing

[er.vansh17091]

Hello Connections,

I've never seen unequal cost load sharing or unequal balancing in prod infra for OSPF.

I want to know do we have such kind of process or can we achieve this ?

If yes what's commands we can use ?

[Sergey Lisitsin]

Hello,

OSPF doesn't support unequal cost load sharing. And in all honesty, that usually not a good idea even in EIGRP that does support it. You want consistency for your traffic flows, whereas different cost/metric links will have inconsistent delay as well, which is bad.

[balaji.bandi]

OSPF is wrong protocol for unequal LB, if that is requiredment use EIGRP does that work.

[Georg Pauwen]

Hello,

OSPF only does equal-cost load balancing indeed, but you can 'trick' it into believing that multiple links have the same cost by using the 'bandwidth' or the 'ip ospf cost' command on the interface, using the same values.

Beware of the unpredictable results mentioned in Sergey's post.

[MHM Cisco World]

OSPF not support unequal 
EIGRP support unequal 

[balaji.bandi]

OSPF not support unequal 
EIGRP support equal 

EIGRP support un-equal paths (hope you meant to say this i guess.

[Joseph W. Doherty]

I believe PfR-PIRO is capable of providing unequal load balancing while using OSPF.  NB: PfR is an additional feature on some IOS and likely will require a more feature set version of IOS and/or an additional license.

[er.vansh17091]

Hi,

Can you pls explain it bit more?

[balaji.bandi]

here are the good resources, as suggested to work for you you need to right IOS and hardware to work.

https://blog.ine.com/2011/11/01/cisco-performance-routing-pfr-optimized-edge-routing-oer

https://skminhaj.wordpress.com/2016/02/15/load-balancing-using-performance-routing-pfroer/

http://brbccie.blogspot.com/2012/10/oerpfr-configuration.html

[Joseph W. Doherty]

PfR has the ability to dynamically load balance (i.e. actual link load) in proportion to link capacity.  I.e. It will attempt to insure link loading is the same percentage on the links it controls.  It doesn't really care how the routing protocol balances, or not, the links.

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/pfr/configuration/xe-3s/PfR_Protocol_Independent_Route_Optimization.html

Before PIRO, PfR could only move flows about using static routes or BGP.