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ip ip ospf cost 35

what the below command do under Tunnel interface

ip ospf cost 35


Re: ip ip ospf cost 35


Instead of leaving OSPF to calculate the cost based on the bandwidth defined under the tunnel interface you are manually enforcing the ospf cost under the interface so that ospf process can use the same..

Can you also try giving show ip ospf interface .. the output of this command will reveal more facts on how the routing has been designed over there in your place..

Do refer this link for more info on the same..



Re: ip ip ospf cost 35

Hi ,

To explicitly specify the cost of sending a packet on an interface, use the ip ospf cost command in interface configuration mode

You can set the metric manually using this command, if you need to change the default. Using the bandwidth command changes the link cost as long as this command is not used.

The link-state metric is advertised as the link cost in the router link advertisement. We do not support type of service (ToS), so you can assign only one cost per interface.

In general, the path cost is calculated using the following formula:

10 to the power 8 / bandwidth

Using this formula, the default path costs were calculated as noted in the following list. If these values do not suit your network, you can use your own method of calculating path costs.

56-kbps serial link--Default cost is 1785

64-kbps serial link--Default cost is 1562

T1 (1.544-Mbps serial link)--Default cost is 64

E1 (2.048-Mbps serial link)--Default cost is 48

4-Mbps Token Ring--Default cost is 25

Ethernet --Default cost is 10

16-Mbps Token Ring?Default cost is 6

FDDI - Default cost is 1

X25 - Default cost is 5208

Asynchronous - Default cost is 10,000

ATM - Default cost is 1


The following example sets the interface cost value to 65:

ip ospf cost 65



Re: ip ip ospf cost 35

To put it simple, u r manualy defining cost on interface for OSPF process to take this cost for calculating aggregate cost to destination.

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