The OSPF route of Ne40 travels through the link whose cost is large,intead of the small one

Publication Date:  2012-07-27 Views:  149 Downloads:  0
Issue Description

S8016---ne40(1)--ne40(2)

  |____MA5200_____|

On S8016 and ne40(2), confiugre two same downlink network segments whose destination is MA5200 , the next hop is the static route with MA5200 interface ip, and the static route employs ospf,On ne40(1), check the routing table and detect ne40(1) whose cost is 501, to learn the static route from ne40(2), instead of learning this route from S8016.

Alarm Information
Null
Handling Process
On ne40(1), detece the E type of two learned two routes via disp ospf  lsdb ase uncommunicates,one is e type1 learned from ne40(2), the other is e type2 route learned from S8016. According to the routing theory of ospf, select E1 exterior route preferentially. Change the exterior route employed by ne40(2) to 2.
Root Cause
In the case, notice the route selecting theory of ospf is route preference:
1.intra-domain route
2.inter-domain route
3.E1 exterior route
4.E2 exterior route
according to the phenomenon, we know the problem is to employ various exterior routes, because the preference of exterior routes of E1 is higher than that of E2, so the router will select E1 routes preferentially.

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