Ethernet Switching
Ethernet Switching

how do i change ospf route metrics??

02.24.10   |  
‎02-24-2010 10:28 PM

hello all- I have two Ex4200 switches connected to each other and running ospf. I would like to change metric on few routes when sent from switch1 to switch2 and while keeping default metrics on all other routes. I tired export policy from the  advertising switch but it did not work..then i tried import policy on the receiveing switch..which also did not work. How can i accomplish this. I tried the following policy

 

policy-statement test-subnets {
    term test-subnets {
        from {
            route-filter 10.1.0.0/23 exact;
            route-filter 10.1.16.0/23 exact;
        }
        then {
            metric 5;
            accept;
        }
    }
    then accept;
}

 

applied it as export and then also tried it as import on the receving switch...TIA

3 REPLIES
Ethernet Switching

Re: how do i change ospf route metrics??

02.25.10   |  
‎02-25-2010 12:15 AM

Hi,

 

you must not alter OSPF metrics with the help of policies because that would break the SPF algorithm. The metric is calculated based on the costs of a specific interface by dividing the reference bandwidth (100 MBit) by the interface bandwidth with always rouding up to 1. So Gigabit interfaces get a cost of 1.

 

In case that these two /23 routes come from directly connected interfaces, you can modify the interface cost (metric) by using this command:

 

set protocols ospf area x interface ge-a/b/c.0 metric y

 

You can also modify the reference bandwidth by "set protocols ospf reference-bandwidth".

 

Regards,

Dominik

JNCIE et al.

--
The Axiom of Choice is obviously true, the well-ordering principle obviously false, and who can tell about Zorn's lemma?
Ethernet Switching

Re: how do i change ospf route metrics??

02.26.10   |  
‎02-26-2010 09:41 AM

Hi  Dominik , but what if he wanted to chage the metric for specific routes ? your method will change metric for all routes

Ethernet Switching

Re: how do i change ospf route metrics??

02.26.10   |  
‎02-26-2010 11:56 AM

Hi,

 

this came also to my mind, but after submitting my post. Smiley Happy As he also posted the question under the Routing topic I did not supplement a clarification.

 

Regards,

Dominik

JNCIE et al.

--
The Axiom of Choice is obviously true, the well-ordering principle obviously false, and who can tell about Zorn's lemma?