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Regarding ospf cost


Hi team,

We have 12K GSR at one end an 7200 router at other end. ospf configured for our remote offices with 2 links for redundancy.

Primary will be of 100Mbps and secondary will be 34Mbps. But the ospf cost o the links will be showing as 1 for both the links.

higher bandwidth link should has low cost right ?. We have not explicitly defined any reference bandwidth.

Please giude wha coul be the issue.

Thanks & Regards,


5 Replies 5

mr Anh

Do you use Fast Ethernet interface for 2 link?

Hi Anh,

Thanks for the reply.

We are using one of the sub-interface in Gigabit port for 34Mbps, and One E1 channel from the Sonet controller for 2Mbps connectivity.

So please guide me what could be the issue.

Hi naveen,

Can u show the configuration of 2 interface?


Rising star
Rising star

Hi Naveen,

Please refer the link for OSPF interface cost table for various interface types:

However, suggest you explicity define the ospf cost on the interface in order to manage your primary and secondary links.

Pls rate if helps !

Best Regards,

Guruprasad R

Giuseppe Larosa
Hall of Fame Master Hall of Fame Master
Hall of Fame Master

Hello Naveen,

the cost on 34 Mbps should be higher if both costs are 1 this means that ip ospf cost has been used on one of the two links (the 34 Mbps link) or that the auto-reference bandwidth has been lowered from defaul value 8 (but you have noted that this has not been changed)

check configuration with

show run interface type x/y

change the ip ospf cost 1 command or remove it under the serial interface

Do it on boh routers both ends of the link

Hope to help


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