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binoy.baby
Beginner

OSPF E1 path selection

Ospf  E1 route preference  via 2 mpls links.

We have a MPLs connection via level 3 from India to US running OSPF,  recently we got second MPLS link from AT&T now since AT&T is running BGP over their cloud we asked them to run ospf on both the sides facing the company, BGP was redistubuted to OSPF with metrics of 2000 type 1  on the AT&T .  L3 has less metrics (E1  -110/45) compared to the E1 110/2001 ) but as soon as I connected AT&T to Coreswitch .  the AT&T routes are installed (Core-India),  would like to know why AT&T is being preferred even after the metric are higher  . Primary should have been the L3.

IndiaCore---->OSPF Area 3.3.3.3 ||  (AT&T Router India )||  -----AT&T MPLS Cloud (BGP)-----> || US  (AT&T router)|| area 0<-->Us core

IndiaCore----->OSPF area 3.3.3.3 || (L3 router India )|| -----L3 Mpls (ospf) ---->||(L3  US )|| ---Us core

I do understand that if the routes  on At&T was E2 , E1 routes from L3 would have been preferred.

How do I make L3 link more believable.  Is that because the AT&T router has a gig and L3 has 100 mb, 

* India Core Connects to L3 and At&T on Layer 2.

2 REPLIES 2
Alessio Andreoli
Contributor

Hi,
Use the distance command below your ospf process. By the way, because a redistribution is in place it may be possible that the routes are installed because the equal AD. Although the above command should help you can just try to modify the behaviour at the redistribution point by a route-map or changing your AD value on the less desired link (AD = 111 for example). If you do not want to play with this, it could be useful the process and interface config of primary and secondary link


Hth
Alessio

Sent from Cisco Technical Support iPad App

Hi Andreoli,

The AT&T Engineer made the distributed route to E2 ( 110/2000) , but still AT&T routes are installed on the IN Core, Other provider routes are of E1 type ( few with E1 110/43) 110 /53 if i disconnect AT&T  .  E1 should be preffered over  E2 right , why is that not happening .

Regards,

Binoy