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Beginner

Unequal load balance and OSPF

Hi

Eigrp, ospf, BGP all are support equal load balance.

But if I have HO and 3 branches . Ho connected all branches 3 ISP line.

If 3 ISP is unequal metric and if I run OSPF then data is transfer only one path.

that means no load balancing among the path.I know with the EIGRP can be done Unequal load balance. so with OSPF its not possible.

pls easily explain .

Thanks

Biplob

17 REPLIES 17
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Paolo,

I do not currently have test equipment to inject traffic but the show command I provided is the actual FIB, so unless CEF is disabled on a specific interface, the FIB is used to forward packets and these packets will be forwarded based on the hashing buckets seen in the show command as can be seen with the following command:

routerD#sh ip cef exact-route 192.168.24.4 192.168.13.3

192.168.24.4 -> 192.168.13.3 : Ethernet0/0 (next hop 192.168.12.1)

routerD#sh ip cef exact-route 192.168.24.4 192.168.13.1

192.168.24.4 -> 192.168.13.1 : Ethernet0/0 (next hop 192.168.12.1)

routerD#sh ip cef exact-route 192.168.24.4 192.168.13.2

192.168.24.4 -> 192.168.13.2 : Ethernet0/0 (next hop 192.168.12.1)

routerD#sh ip cef exact-route 192.168.24.4 192.168.13.4

192.168.24.4 -> 192.168.13.4 : Ethernet1/0 (next hop 192.168.23.3)

routerD#sh ip cef exact-route 192.168.24.4 192.168.13.5

192.168.24.4 -> 192.168.13.5 : Ethernet0/0 (next hop 192.168.12.1)

routerD#sh ip cef exact-route 192.168.24.4 192.168.13.6

192.168.24.4 -> 192.168.13.6 : Ethernet1/0 (next hop 192.168.23.3)

routerD#sh ip cef exact-route 192.168.24.4 192.168.13.7

192.168.24.4 -> 192.168.13.7 : Ethernet1/0 (next hop 192.168.23.3)

routerD#sh ip cef exact-route 192.168.24.4 192.168.13.8

192.168.24.4 -> 192.168.13.8 : Ethernet1/0 (next hop 192.168.23.3)

routerD#sh ip cef exact-route 192.168.24.4 192.168.13.9

192.168.24.4 -> 192.168.13.9 : Ethernet0/0 (next hop 192.168.12.1)

routerD#sh ip cef exact-route 192.168.24.4 192.168.13.10

192.168.24.4 -> 192.168.13.10 : Ethernet0/0 (next hop 192.168.12.1)

As far as your second question, yes there are customers using unequal cost load balancing in their production networks.

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
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Very good, you provided the exact type of information that has been missing in previous discussion on the subject, and I've rate your post, thanks!

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I hope you are finding some of this useful.

And just to let you know, you might be able to use staic routes for unequal loadbalancing, it depends on your setup.

Are you using MPLS, Frame relay or something totaly different?